A small but capable predator of insects, reptiles, and small birds, the Loggerhead Shrike lacks the powerful talons of raptors, but makes up for it by impaling prey on thorns or barbed wire to hold it for eating. Loggerhead Shrikes first kill birds and reptiles with a bite to the neck.
Loggerhead Shrikes are known to chase Brown-headed Cowbirds away from their nest, though there are a few records of nest parasitism. Young shrikes begin practicing the motions of impaling prey at just three weeks of age, though they don’t actually make a kill until about six weeks of age.
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Description of the Loggerhead Shrike
The Loggerhead Shrike has dark gray upperparts, pale underparts, black wings with white patches visible in flight, a thick, black line through the eye, and a short, black, slightly hooked bill.
Seasonal change in appearance
Juveniles are similar, but with lightly barred underparts.
Loggerhead Shrikes inhabit open country with scattered trees, fences, or brush.
Loggerhead Shrikes eat large insects such as grasshoppers, as well as rodents and small birds.
Loggerhead Shrikes forage by observing from a perch and then rapidly flying down to capture prey, which they dispatch with their hooked bill. Shrikes often impale prey on barbed wire fences or thorns for later use.
Loggerhead Shrikes breed from southern Canada south throughout most of the lower 48 states except in the northeastern U.S. They retreat from some northern portions of their range during winter. The population has declined substantially in recent decades, though the reason is not clear.
Bent Life History
Visit the Bent Life History for extensive additional information on the Loggerhead shrike.
The shape of a bird’s wing is often an indication of its habits and behavior. Fast flying birds have long, pointed wings. Soaring birds have long, broad wings. Different songbirds will have a slightly different wing shape. Some species look so much alike (Empidonax flycatchers) that scientists sometimes use the length of specific feathers to confirm a species’ identification.
Wing images from the University of Puget Sound, Slater Museum of Natural History
Loggerhead Shrikes occasionally capture prey of meadowlark size.
The Loggerhead Shrike’s habit of impaling prey on thorns or barbed wire gave rise to its nickname of Butcherbird.
The typical song is a two-syllable “keeak.”
The Northern Shrike has a longer bill and a narrower black mask. Juveniles retain a barred breast through the winter, while Loggerhead Shrike juveniles lose the barring by early fall.
The Northern Mockingbird lacks the strong black mask, wings are grayer, more noticeable white wing patches.
The Loggerhead Shrike’s nest is a bulky cup of twigs, grasses, and weeds placed in a dense tree or shrub. Thorny vegetation is preferred.
Number: Usually lay 4-5 eggs.
Color: White with darker markings.
Incubation and fledging:
The young hatch at about 16 days and fledge at about 18 days, though remaining dependent on the adults for some time.
Bent Life History of the Loggerhead Shrike
Published by the Smithsonian Institution between the 1920s and the 1950s, the Bent life history series of monographs provide an often colorful description of the birds of North America. Arthur Cleveland Bent was the lead author for the series. The Bent series is a great resource and often includes quotes from early American Ornithologists, including Audubon, Townsend, Wilson, Sutton and many others.
Bent Life History for the Loggerhead Shrike – the common name and sub-species reflect the nomenclature in use at the time the description was written.
LANIUS LUDOVICIANUS LUDOVICIANUS Linnaeus
HABITSCONTRIBUTED BY ALEXANDER SPRUNT, JR.
Among the earliest ornithological memories of the writer is the search for nests of the “French mockingbird” amid the myrtle bushes of the back beach of Sullivans Island, near Charleston, S. C. On this narrow barrier of sea sand, which has figured so largely in history since the days when Sir Peter Parker’s fleet was turned away by the batteries of palmetto-logged Fort Moultrie, many Low Country bird records have helped make ornithological fame locally. It was a happy hunting ground for several kindred spirits of schoolboy days, and birds’ eggs were mediums of exchange for various and sundry other specimens of beach and marsh. In few other areas since has the writer ever found the loggerhead shrike such a characteristic bird and will always associate it with this spot for it was among the first half dozen species of his “life list.” Though having shown it to many others for their “first” since, long acquaintance with it has not dimmed interest in its attractive way of life.
Misunderstood and rather frowned upon by the uninformed, the loggerhead is one of the decidedly beneficial and valuable birds of its range and its activities are a natural asset of no mean proportions. As its name implies, it was described from Louisiana, by Linnaeus, but the bird is no more typical of that State than many other parts of its habitat.
Spring: There is little change in the seasonal numbers of the loggerhead in most of its range except in the northern limits. Elsewhere the population remains largely static as the species is resident throughout most of the country it frequents. Certainly, numbers in coastal South Carolina, Georgia, most of Florida, and the Gulf coast do not vary appreciably. In North Carolina (eastern) there is a slight southward movement in fall and a return in spring but it is not pronounced. Some confusion may exist in that State by the overlapping occurrence of L. Z. migrans and the difficulty of differentiating between the two in the field. That both ludovicianus and migrans occur together there has been demonstrated by T. D. Burleigh, who secured specimens of each at Tarboro, Edgecombe County, N. C., in January 1931 (Pearson and Brimley, 1942).
Courtship: The courtship performance is not particularly elaborate or widely commented upon. It is undertaken with much fluttering of the wings and some spreading of the tail in display on the part of the male. Considerable erratic chases of the female occur at times, the birds twisting and turning almost like sandpipers over the surf, for apparently the female does not take very kindly to watching the male display at length.
Audubon (1842) was somewhat cavalier in his opinion of this phase of the loggerhead’s way of life. He says flatly that “the male courts the female without much regard, and she, in return, appears to receive his haughty attentions with merely just as much condescension as enables her to become the mother of a family, whose feelings are destined to be of the same cold nature.” He follows this later in his account with a- quotation from the Rev. John Bachman as follows: “You speak of the male showing but little attachment to the female. I have thought differently, and so would you were you to watch him carrying * * * a grasshopper or cricket to her, pouncing upon the Crow and even the Buzzard, that approach the nest, and invariably driving these intruders away. Indeed I consider these birds as evidencing great attachment toward each other.”
Living in the same area from which Dr. Bachman wrote these words, and where he saw so much of the loggerhead, the writer agrees with him completely. He has never noted any trait that would tend to prove that the loggerhead was lacking in domestic responsibility.
Nesting: This species is an early nester, even in regions where early nesting is indulged by other avian forms. It is another point of similarity to the birds of prey, for the loggerhead is decidedly reminiscent of that order in many ways. Though Florida shows the earliest dates for nesting (which is t.o be expected) there is not a great deal of difference between it and coastal South Carolina or Georgia. In all of these the loggerhead sometimes begins nest-building in February, but March is more nearly normal.
Arthur H. Howell (1032) lists February 9 as an early Florida record, this nesting being near Gainesville. The birds usually begin to build in the Lake Okeechobee region late in February, and are incubating during the first week of March. In the Pensacola area (much to the north and ~vest) the latter part of March is more typical, and F. M. Weston (MS.) states that the first brood is raised by “early April.” Nests with eggs found by him in mid-May he says are “almost certainly a second brood.” Similar dates are typical of southern Georgia. Fresh eggs on or after the middle of May in either region are doubtless a second laying.
C. H. Pangburn (1919) believes that the loggerhead is the third commonest nesting bird in Pinellas County, Fla., and that the young are flying the last week in March. 5. A. Grimes (1928) puts it second in the Jacksonville area, outnumbered only by the mockingbird.
Dr. E. E. Murphey, of Augusta, Ga., has a nesting date of March at that locality. Arthur T. Wayne (1919) states that he was informed by G. R. Rossignol that the latter found a nest and five eggs at Savannah on February 15, 1919. Nest-building by this pair began on January 16. This is a very early date and may be considered the earliest Georgia record.
Nesting in South Carolina in some years varies little from that in Florida. Wayne (1910) has noted birds mated by mid-February and says that nests are often built late that month. Bad weather in March frequently delays nest construction, however, and not infrequently ~he birds abandon original efforts and start new nests. Average time for the Charleston region is late in March. Files of the Charleston Museum show that incubating birds were found by F. M. Weston on March 18, 1913, and March 19, 1911. Wayne’s earliest breeding record was March 13, 1917. The writer found a nest with five fresh eggs on March 28, 1914. While living in the city of Charleston ho was accustomed to find nests of this species every year on the street in front of his home. There was a line of small live-oak trees planted there (the area was all “made” land, having been reclaimed from the Ashley River), and their thick, tough twigs were ideal nesting sites.
One tree, about 12 or 15 feet high, across the street from his house, always had a nest in it every season, and in 1924 one was built and the young raised by mid-April. On June 22 another nest was built in the same tree about 5 feet from the first one (same pair of birds doubtless), which was still in excellent condition. H. K. Job visited the writer while the first nest was in use and photographed it.
In the northern rim of its range (eastern North Carolina) the loggerhead nests noticeably later than elsewhere. T. Gilbert Pearson and the I3rimleys (1942) list fresh eggs as having been found in Columbus County on May 6, iii l3ladcn County, May 7, completed nests but no eggs. At the same date, however, young just out of the nest were seen! Probably late April would be normal for many breeding pairs, just about one month later than South Carolina birds. Again, at the western terminus of its range the loggerhead is late. Dr. H. C. Oberholser (1938) states that “it breeds in Louisiana from April to June, and there is record of eggs as early as April 16.” If the latter is an early date for Louisiana it is obvious that the loggerhead is far behind its eastern dates in its western home.
The nest itself is built. at medium elevations, never very high and seldom close to the ground: 8 to 15 feet is normal. It picks out heavily twigged growth, though its early habits often reveal the nest to any observer as it is completed before the leaves come out. Young oaks are favorites, and these, of course, retain their leaves. Such trees are widely used in coastal South Carolina, and the species often nests in towns and cities, even on streets carrying considerable traffic.
The loggerhead is a good architect and builder. Though somewhat bulky, the nest is well made and lasts long after its usefulness is over. The materials are usually thick twigs, firmly woven and lined with rootlets or fibers and, in the rural sections, often padded with cotton. The latter is a characteristic item among a varied range of material. Others are string (often used), feathers of various kinds, hair, palmetto fiber, weeds, small sticks, grass, “rabbit-tobacco” (everlasting), rags, and occasionally paper. M. G. Vaiden, of Rosedale, Miss. (MS.), once found a piece of blue bottle glass in a nest! Both sexes work on the nest and very assiduously. Incubation consumes 10 to 12 days, and both male and female engage in the duty. S. A. Grimes (1928) gives 14 days for incubation.
E. R. Ford (1936) gives an account of an unusual nesting site with regard to elevation, which he found at Fort Lauderdale, Fla., on March 5. The birds began building that day “on one of the lower branches of a long-leafed yellow pine. The site was a little more than fifty feet from the ground. * * * Except on one occasion, I had never seen the nest of any Shrike more than eight or ten feet up, [and] I made it a point to observe this one particularly.” This height is very abnormal and can be considered the extreme.
Two broods are usually raised, though in coastal South Carolina there are often three in a season. It is interesting to note that Audubon’s (1842) account is contradictory in that he says in the early part of his biography of the species that “loggerheads rear only one brood in the season” and later, quoting Rev. John Bachman, that “this species breeds twice in a season.” The latter is the correct statement, applying to the greater part of the range.
An example of what amounts to practically colony nesting of the loggerhead is furnished by M. G. Vaiden, of Rosedale, Miss. He says (MS.) that on April 9, 1937, he was driving near the site of the old town of Concordia (Miss.) now inundated by the river. Along the levee was a hedgerow of dwarf thorn bushes or small trees (Crataegus u’niflora), and shrikes were noted flying in and out of them. Careful investigation revealed that nearly every tree held occupied nests, and 14 were found in 13 trees! Eight nests contained eggs; the others were either just completed or still building. Eggs were found in them a few days later. This is a remarkable observation, and the writer has never heard it approached, but Mr. Vaiden says that he once saw another similar instance. This was the finding of seven nests in thorn trees along an unused road also in Mississippi. No two nests were more than 60 feet apart, and it was not over 200 feet from the first to the last nest in a straight line down the road. The writer has often found two or three loggerhead nests in trees fairly close together, the distance of a city block for instance, but never anything that would justify an illustration of colony nesting.
S. A. Grimes (1928) gives an interesting observation of communal use of the same nest by loggerheads as follows:
A nest about eight feet up in an oak, found March 15th, 1925, was built on a thrasher nest of the preceding year. Revisiting this nest a week later, I was much astonished to find seven eggs in it, and two brokcn eggs on the ground below. The eggs were obviously not all laid by the same bird, for five were of a dark ground color and minutely speckled with dark hrown, whereas the set of four, two of which were on the ground, were of a much lighter ground color * * * and there were three solicitous Loggerheads lerating nie on nil sides. This was a plain case of avian bigamy. The nest was destroyed a night or two later, apparently by someone’s treacherous house cat. Within a day or two, the ‘pair” began making a new nest fifteen feet up in a pine sapling * * ~. On April 5th, this nest held five dark eggs and one li~ht egg. Nine days later it contained three light-colored eggs and only four of the dark variety, and in the grass beneath were two of the less densely speckled eggs. This nest subsequently met the fate of the first. At least nineteen eggs, hilt from theni not one Loggerhead to enhance, With futile loquacity and sprightliness, the attractiveness of a hit of shaded street or tree-lined field.
Eggs: [AUTHOR’S NOTE: The sets of e~s laid by the loggerhead shrike may consist of four to six eggs, though four and five are probably commoner numbers than six. These are practically indistinguishable from those of other races of the species, which are well described under the California shrike. The measurements of 50 eggs of this southeastern race, in the United States National Museum, average 24.2 by 18.7 millimeters; the eggs showing the four extremes measure 25.9 by 18.3, 23.6 by 19.9, 22.3 by 18.7, and 23.4 by 17.8 millimeters.] Plumages: [AuTRon’s NoTE: The sequence of molts and plumages is the same as for the migrant shrike, to which the reader is referred.] Food : Tlie local name of the loggerhead in many localities, i. e., butcherbird, is indicative of the popular opinion of its food habits. However, popular opinion in this case, as in so many others, is often erroneous in its conclusions. The basis for the rather generally held belief that the species is injurious lies in the undoubted fact that it sometimes does take small birds. This habit., however, is not widely or even generally indulged and is much more the exception than the rule. The condemnation of the bird for it, therefore, is again reminiscent of the treatment meted out to the birds of prey, so widespread and detrimental to that group.
In certain respects the loggerhead exhibits predatory habits, and if such a combination can be visualized it might be said to be a passerine raptor! Not. possessing talons with which to grip prey while feeding, it resorts to the well-known and thoroughly characteristic trait of impaling its victims upon thorns, barbed wire, or other sharp projections; hence the local name butcherbird.
Naturally, what birds are taken are small ones. Little of definite information appears in the literature regarding specific varieties, but there is much generalization. Sparrows and warblers appear to make up the bulk of small-bird prey. The writer has seen myrtle warblers (Dendroica coronata) victimized on at least two occasions, and English sparrows (Passer domesticus) are fairly often taken in cities and towns, probably because of the ease with which they are secured.
Wright and Harper (1913) relate that they saw a loggerhead chasing a red-cockaded woodpecker (Dryobates borca7is) in the Okefenokee Swamp in southeastern Georgia and found the remains of one young and one adult bluebird (Sialia sialis) on a stump, also the work of the shrike. Pearson and the Brimleys (1942) record the finding of the dried body of a myrtle warbler on a thorn by C. S. Brimley and a similarly treated chipping sparrow (Spizella passerina) by Pearson. The brains of the sparrow had been eaten from a cavity in the back of the skull. Observations by F. H. Craighill are quoted by these authors to the effect that he has seen “young birds” hanging in small plum trees but apparently no identification was made of the young. Craighill is further quoted as saying: “Last week I saw a shrike pursuing a small bird with evident felonious intent. I bad never before seen that here [Rocky Mount, N. C.] except when there was snow on the ground and shrike food was scarce.” Again, there is no identification of the “small bird.”
11. L. Stoddard writes me that a shrike got into a banding trap of one of his neighbors near Beachton, Ga., and killed a chipping spare row. “The queer part of the thing was that there was a stiff straw through the sparrow’s neck,” he says. “I went down and got the bird and found that the shrike had pinched at the neck and broken it in several places. The only explanation of the presence of the straw that occurs to me is that the instinct to hang prey on a twig or thorn is a very strong one. The shrike would have been unable to eat the sparrow in the usual way as there was no place in the trap to hang it (and shrikes are probably unable to hold prey in the feet as do~ birds of prey). Hence it had worked the stiff straw through the neck in an attempt to anchor the bird for eating. At first glance this would seem impossible, but when we remember the skill in nest-building it does not seem so remarkable. The straw was stuck through between the gullet and windpipe just above the breast in the exact spot where shrikes usually hang the small birds they kill.”
E. G. Holt (1913) watched a loggerhead near Barachias, Ala., kill a mockingbird (AUm’us polyglottos). It was during a severe freeze, and the shrike attacked and pinned down the mocker, striking it repeatedly with its beak and soon killing it. Bolt then interrupted proceedings by picking up the dead bird and examining it; then, as he held it in his outstretched hand, the shrike returned and attempted to take it. Subsequent observation revealed that it removed the mockingbird’s entrails through a small hole above the kidneys.
Loggerheads rather frequently incur the wrath of owners of canaries in attacks on these cage birds. When a cage is placed on a porch oi anywhere outside, it seems to be an irresistib]e attraction to shrikes in the vicinity. When one alights on the cage it produces panic in the canary, which, instead of remaining in the middle of the perch where it would be perfectly safe, often sticks its head out between the bars. Thereupon it is clipped neatly off by the shrike, or so pierced by its beak that death is the result. The writer’s mother lost three canaries in this way while summering on a beach resort near Charleston, S. C., a place where loggerheads were abundant.
The food of the loggerhead is nearly entirely animal in character. Food of eastern shrikes is wholly of this category, though examination of some of the western subspecies showed that vegetable matter amounted to 2.5 percent (F. E. L. Beal, 1912). Professor Beal’s researches further revealed that the eastern bird shows a breakdown of 68 percent insects, 4 percent spiders, and 28 percent vertebrates. These studies were based on the contents of 88 stomachs. Distinct seasonal variation appears in the food take, for it has been established that the warm seasons show a preponderance of insect prey secured, while in winter the greater part consists of mice and small birds.
Among the insects the Orthoptera compose the largest item. Grasshoppers and crickets make up 39 percent. In August and September these constitute 70 percent of the total food, though they are taken in every month of the year. Among the crickets, which are not so acceptable as grasshoppers, the so-called wood cricket is often taken, numbers of the genus Steno pelmatus being particularly noticeable. These insects usually live under leaves and stones and avoid light but not to the extent of remaining undetected by the remarkable vision of the loggerhead.
Beetles are eaten to the amount of somewhat in excess of 16 percent. Ground -beetles (Carabidae) and carrion beetles (Silphidae) compose 7 percent of this total; the rest are harmful varieties. Ants and wasps are represented by only 3 percent, the latter outnumbering the former. Moths and caterpillars form 4 percent. Bugs, flies, and a few other odd insects total 5 percent.
Spiders make up 4 percent of the loggerhead’s diet, while the vertebrates (28 percent) include mammals, birds, and reptiles. Of these, mice compose by far the bulk. A. H. Howell (1032) quotes Judd (1898) as saying that mice are taken “at all seasons and in winter comprise half the food.” He adds that “birds make up only 8 percent of the food for the year.” Certainly, this predilection of the loggerhead for mice, and the fact that half the winter food is made up of these animals, should go far to prove the great value of the shrike to agricultural interests. Audubon went the length of saying that mice “form the principal food of the grown birds at all seasons.”
Alexander Wilson (Wilson and Bonaparte, 1832) wrote that on the rice plantations of Carolina and Georgia “it [the loggerheadi is protected for its usefulness in destroying mice.” He describes it as sitting near stacks of rico and “watching like a cat; and as soon as it perceives a mouse, darts on it like a Hawk.” Evidently the loggerhead was more appreciated in Carolina then than it is now.
Occasionally, extraneous items appear in the shrike’s food, or attacks are made on forms not usually associated with its diet. N. C. Longee, of Gainesville, Fla. (Howell, 1932), saw a shrike bring a number of large, live cattle ticks to a barbed-wire fence and impale them thereon. Howell once saw a lizard being eaten. F. M. Weston (MS.) states that he witnessed near Pensacola, Fla., the chase of a bat by a shrike on “a biight summer day,” but the animal eluded two attacks and escaped. The writer has seen a loggerhead chase a bat once and failed to secure it. Weston adds that he once found a small terrapin of “quarter-dollar size” that had been taken and impaled by a loggerhead. E. S. Dingle, of Huger, S. C., writes (MS.) that he saw a loggerhead kill a frog, fly away with it in the beak for a short distance, and then transfer it to the feet in flight. The frog was carried about 200 feet in this manner to a live-oak tree.
Audubon (1842) quotes the Rev. John Bacbman as saying: “I have seen one [shrikel occupy himself for hours in sticking up [on thorns] * * * a number of small fishes that the fishermen had thrown on the shore * * *~ The fishes dried up and decayed.”
Pearson and the Brimleys (1942) give an interesting observation on a shrike “larder” in a residential section of High Point, Guilford County, N. C. It was composed of “no less than fifteen small snakes” impaled on the thorns of a bush. They also state that F. H. Craighill, of Rocky Mount, N. C., found a loggerhead’s cache of a snake, a crayfish, and a grasshopper.
Alluding once more to its bird-killing propensities, observations by S. A. Grimes, of Jacksonville, Fla. (1928), reveal that the loggerheads “take fledgling English Sparrows from their nests in holes made by woodpeckers. Perched in the entrance, heedless of the frantic chattering of the sparrows without, the Shrike, in each instance, appeared to be having no little difficulty in seizing one of the young sparrows. The squealing victim was invariably held by the head. On one occasion the struggling sparrow succeeded in freeing itself, but was recaptured and promptly thrust on a barb of a nearby fence.”
Behavior: The loggerhead presents a striking combination of absolute immobility and intense activity. To see one sitting on a telephone wire awaiting prey is to see a bird as motionless as if it were cast in bronze. The next moment it may be dashing through the air like a winged meteor to pounce accurately upon a spot many yards away. These alternating periods of activity and inactivity arc very characteristic.
Essentially a bird of open country, it is a still hunter in the main and always chooses an elevated and conspicuous perch. This may be the topmost twig of a tree or bush, roadside wires or fences, or any such advantage giving a wide and uninterrupted view. Charlotte H. Green, however (1933), states that the bird has “another method of hunting. Like the crows, he sometimes sneaks upon his victiiu from the ground.” She gives no specific observation relating to such procedure, and it must be a rather uncommon occurrence. The writer has never happened to witness it in his long experience with the species, and certainly it is not freely indulged.
The vision of t.he loggerhead is phenomenal, even for a bird. That it can and does see insects at remarkable distances is unquestioned. When living in the Battery Section of Charleston in an area then being developed residentially, the writer has often sat on the porch and watched loggerheads hunting in adjacent vacant lots. Frequently a bird would pitch off the wires and glide, or fly, 50 to 70 yards in a direct line to a spot in the grasses and seize a grasshopper. No hovering or hesitancy is shown in these sudden dashes. The bird goes directly to a specific spot, and there is no doubt whatever that the intended prey was seen before the bird left the perch.
Weather affects the activity of the loggerhead because it reacts on the food supply. S. A. Grimes (1928) says: “Two of the elements greatly facilitate the capturing of food for the Shrike. Heavy rains drive the subterranean inhabitants to the surface, where they are exposed to the bird’s keen sight; and the grass fire, routing numberless insects, form a veritable cornucopia for this and other species.” Weather has adverse effects also as witnessed by F. M. Weston, of Pensacola, Fla., who says (MS.) : “After the prolonged freeze of January 1940, both shrikes and sparrow hawks (Falco .sparverius) disappeared from this region for the rest of the winter.” ‘the absence of two species sharing the same sort of food leads him to believe that intense and prolonged cold “did away with the winter insect life right down to the grass roots” a most reasonable and logical conclusion.
The flight of the loggerhead is accomplished by very rapid vibrations of the wings, an almost labored fluttering, it seems. It does not, however, give the impression of wasted energy. Periods of sailing intervene, and the course is usually at low elevations. When selecting a perch it sweeps upward to it in a steep glide. When leaving, it drops a few feet, then catches the air with the wings, and proceeds with the characteristic rapid beats. The speed attained in flight has been given by Gordon Aymar (1935) at 22 to 28 in. p. h. based on “specific records.”
A sidelight on the flight is indicated by A. L. Pickens, of Paducah, Ky., who writes (MS) : “Another name for the loggerhead shrike in the South is cotton-picker, probably from its bobbing waves of flight above the cotton rows, as if darting down here and there to pluck off a fleece.” The writer has never heard this name applied to the bird anywhere in its range but would think that its derivation would be much more apt to apply to the frequent use of cotton in nest-building than the “probable” reason given above.
The outstanding trait of the loggerhead is its habit of impaling victims on thorns, barbed-wire fences, and similar sharp projections. This accounts for the local name so universally in vogue: butcherbird. Supposedly, it is done for the reason of storing a food supply, but probably also to assist in tearing the prey apart in many cases, as the loggerhead does not have very strong claws. The future food supply idea is, no doubt, much more applicable to the northern shrike (Lanius borealis), for the food in the loggerl~ead’s range is so abundant and constantly avm~ilable that there is rarely an occasion when the bird has to resort to already secured prey. Conversely, there are doubtless times when the northern bird is hard put to it in winter and uses a larder far more frequently. Regarding the loggerhead, indeed, many have questioned whether it ever does return to impaled prey. The frequent finding of dried bodies of birds, snakes, and insects by many observers, ignored completely by the bird, leads to such an impression.
Pearson and the Brimleys (1942) states: “Whether this bird hangs up food for future use has not been definitely established. The authors of this book have not known shrikes to return to the grasshoppers, beetles * * * that they had impaled.” However, it is certainly the case that this ia sometimes done. H. L. Stoddard (MS.) writes me: “There used to be a question in my mind as to whether shrikes ever returned to their food caches, after such prey had dried out through hanging on a twig or wire. I settled this question to my satisfaction one day in the yard here at home [Sherwood Plantation, Grady County, Ga.]. Noticing a shrike flying through the yard ~vith a sizable object, I grabbed up a clod and threw it at the shrike, which dropped the object. This proved to be a brittle dead twig about 2 inches long, to which firmly adhered the dried remains of a myrtle warbler. Evidently the shrike had returned to prey hung many days before and in trying to remove the warbler had broken off the twig that anchored it.”
So, then, it is safe to conclude that the loggerhead does not ordinarily return to impaled prey but occasionally does so.
Curiously enough, Audubon (1842) makes this remarkable statement: “I have never seen it attack birds, nor stick its prey on thorns in the manner of the Great American Shrike.” Whether he means that he did not actually see this accomplished, or whether he never found any evidence of it, is not clear, but it seems that the latter was meant. If so, it is almost beyond belief, since he spent much time in the loggerhead’s range, and it would be most natural to conclude that he would have found something of the sort during his expeditions. He does, however, quote the Rev. John Bachman, who wrote him that he had “never found either this or the Northern Shrike return to such prey for food. * * * I have seen them alight on the same thorn bush afterwards, but never made any use of this kind of food.”
Some evidence that the loggerhead occasionally indulges in a kind of play, reminiscent of certain hawks, is contained in an observation related to me by Herbert R. Sass, of Charleston, S. C. He happened to be watching a pigeon sitting on the roof of his house one day, when a loggerhead suddenly appeared in the air behind and above the pigeon and, diving straight at it, struck it a resounding blow in the back I The startled pigeon was knocked completely off the roof and fell several feet before recovering its balance and spreading its wings. No effort was made by the shrike as a follow-up; apparently it simply indulged a sudden impulse, as it cannot be supposed that it meant to seek the pigeon as prey.
An observation by E. J. Reimaun (1938) reveals a rather unusual encounter between a loggerhead and a yellow chicken snake (Elaphe q. quadrivittata) at Marco Island, F] a. While perhaps an indication of an attempt to secure food, it may have been an instance of the tendency to play, similar to that above, for the size of the snake would rather preclude the idea of the bird being able to despatch it. At any rate, Reimann says that noting a group of men watching something on the ground, he found the shrike attacking the snake. He says:
The snake would crawl forward over the ground, and the shrike would fly down from a telegraph wire and, hovering over the snake, would pounce down, grasp the snake by the tail, rise in the air about six inches, and let the tail drop. The snake would immediately fall into a defensive coil and the shrike would alight on the ground about two feet away. It remained there until the snake again wandered off; then it would hover, pounce, and grasp the tail as before. Sitting along a telegraph wire close by, were four newly fledged young shrikes * * * a Mockingbird was also perched on the wire, hut the young shrikes took no part in the combat, flue to coming dusk, the shrikes finally moved off and I threxv the snake under an old building, to save it from the crowd that had gathered there.
Another instance of a shrike-snake encounter is submitted by M. G. Vaiden (MS.), hut it appears to be directly an attempt at securing food. Driving along a country road on July 4,1926, he saw a shrike flying across ahead of him carrying, with great difficulty, a snake in its beak. At last it reached the top of a telephone pole, and there a real battle took place. The snake was very much alive and twisted, beat, and turned energetically while the shrike kept striking at it with its beak. After several minutes of watching, be states, “I broke up this feeding, as I had more feeling for the snake than for the shrike.” Throwing a clod or two at the pair was enough to drive the bird off, and the snake dropped to the ground, still alive but somewhat “bunged up.” It proved to be a rough-scaled green snake (Opheodrys aestivus) and measured 16½ inches long. lIe concludes by adding: “Unfortunately I did not weigh this reptile, but I know that the shrike was handling much more than its own weight. The lifting power of the shrike must be more than the average expected of small birds.” This is a very interesting observation as it reveals the loggerhead as proportionately more powerful than the bald eagle (Haliaeetu8 leucocephal us). The latter is said by most authorities to be unable to lift more than its own weiaht or at the maximum, very little more. The shrike in the foregoing account was handling “much more” than its own weight, though Mr. Vaiden does admit that the snake was not actually weighed. None the less, it is a striking illustration of the virility and determination embodied in this passerine species.
The loggerhead maintains definite territorial limits and protects them assiduously. S. A. Grimes states that he has often noticed that “each pair of shrikes has an apparently well-defined domain of its own, which it holds defiantly to the exclusion of others of its kind.” Other species often nest in fairly close proximity, however, without molestation.
Some observers have considered the loggerhead as a quarrelsome species, but, though instances of it no doubt take place, the writer has never been impressed with this as a characteristic. On the whole, the bird gets along very well with its avian neighbors, some of which are very close neighbors at times. Audubon (1842) had a rather poor opinion of the loggerhead’s disposition, for he says, in explanation of his drawing, that “I have given you, kind reader, the representative of a pair of these Shrikes, contending for a mouse. The difference of plumage in the sexes is scarcely perceptible; but I have thought it necessary to figure both, in order to shew the quarrelsome disposition of these birds even when united by the hymeneal band.”
Voice: Though the loggerhead has little reputation in vocal performance, it has always seemed to the writer that what attainment is reached has been rather cavalierly treated in the literature. Few descriptions of its notes are complimentary! While it can hardly be said to be a singer, its efforts in spring are worthy of some notice and, in certain individuals at any rate, possess a surprisingly melodious quality. It is true that such notes are interspersed with others anything but musical, but the general effect is a liquid tone that is definitely pleasing.
Howell (1932) says: “The birds are not noisy but most of their notes are harsh and unmusical; occasionally one makes an attempt at singing, which Chapman describes as ‘a series of guttural gurgles, squeaky whistles and shrill pipes.'” It is the impression of the writer that all male shrikes “make an attempt at singing” during the nesting season. In coastal South Carolina and the Okeechobee region of Florida he feels certain that the song is indulged by all mated birds. Shrikes are abundant in both areas, and the writer is intimately acquainted with them. While “guttural” is apt enough to describe many of the notes, and it is the case that “most of the calls are harsh and unmusical,” this applies more to the alarm and call notes than the song, if this term can be employed. Some of the latter are very liquid, flutelike, and appealing, so much so that many observers are surprised to find them issuing from a loggerhead.
Peterson (1939) is rather more generous in his comments, saying that the song of the loggerhead is “similar to that of the Northern Shrike,” which he describes as “a long-continued thrasher-like succession of phrases, harsher on the whole than the Thrasher’s song.” It is this writer’s experience that the loggerhead’s efforts are seldom “long-continued,” but it is refreshing to hear the bird compared to the thrasher! One could ask little better.
Peterson has an able foundation in his comparison in a statement made long ago by one who knew the loggerhead well: the Rev. John Bachman, of Charleston, S. C. It was this genial gentleman’s observations that considerably augmented Audubon’s account of the loggerhead in the Birds of America, the latter saying without reservation that “my friend the Rev. JoIm Bachman has had much better opportunities of studying them.” In regard to the vocal efforts he (Bachman) wrote Audubon (1842) : “You say it has no song. This is true in part, but it has other notes than the grating sounds you attribute to it. During the breeding season, and indeed nearly all summer, the male * * * makes an effort at a song, which I cannot compare to anything nearer than the first attempts of a young Brown Thrush * * ~ï Aj times the notes are not unpicasing, but very irregular.~~ Yet another allusion to similarity with the thrasher’s song comes from A. L. Pickens, of Paducah, Ky., who writes (MS.) : “At times I have had to pause and take note to determine whether the birds’ notes, softened in spring by the mating urge, and in fall and winter by distance, might not be thrasher, sparrow, or bluebird.
A. T. Wayne (1910) states: “Although the song of this species is considered by most ornithologists to be hard and unmusical, I have heard a few individuals which sang very sweetly.”
Economic status: Aside from its undoubted value to agriculture in its considerable destruction of injurious small mammals and insects, a fact well recognized by informed people, the loggerhead assumes added importance to stockmen by reason of a comparatively recent discovery. At the 1929 meeting of the American Ornithologists’ Union in Philadelphia, a paper was read by Dr. Eloise B. Cram (1930) dealing with birds as factors in the control of a stomach worm in swine. While the details of it cannot be quoted here it is of great interest to note the conclusions reached. The investigation resulted “from the discovery made by H. L. Stoddard several years ago that the Loggerhead Shrike (Lanius 1. ludovicianus) in northern Florida, chiefly in Leon County, and in southern Georgia, chiefly in Grady County, were infested with large numbers of roundworms encysted in the wall of the digestive tract. These parasites were identified by the writer as spirurid larvae and the infestation as a case of aberrant parasitism * * * the larvae being in a host other than the correct fimial host and therefore incapable of further development.” Careful study was undertaken of birds so infested, and it was found that the dung-beetle (P/manaeus carnife~) remains in shrikes’ stomachs were “practically one hundred percent heavily parasitized with the same larval roundworm as was found in the shrikes.” Extensive feeding experiments were carried out in order to find the final host of the parasite, larvae taken from shrikes being fed to a series of experimental animals. Coming to the summary of the. entire undertaking the writer quotes Miss Cram again:
Larval roundworms found * * * encysted in the walls of the digestive tract of Loggerhead Shrikes * * were identified * * ns Physocephalus sexalatus, the adult form of which occurs in the stomach of swine. The dung beetles * * were found to serve as the first and normal intermediate hosts of the parasite in this locality [northern Fin, and southern Ga., in counties above named]. Rcencystment of the larvae was found to occur in a wide rariety of animals * * ~. It is pointed out that beetle-consuming animals, of which birds are the most important, are thereforo a significant factor in limiting the degree of infestation of swine with Physoccphaies scxaiotus in such an area.
This is a most interesting account. and revelation and should be of value to those engaged in hog-raising probably in other parts of the Southeast. The loggerhead is an abundant bird in the cattle-ranch areas of Florida, notably tbe Lake Okeechobee and Kissimmee Prairie regions, and it may be that its value in that area is equal to good done in the more northern parts of the State. At any rate it is commended to all who are interested in the welfare of the loggerhead and its economic importance to humanity, directly and indirectly.
Field marks: The loggerhead is hardly to be confused with any other species except the mockingbird. To the latter, however, it bears such a resemblance that many inexperienced observers confuse the two birds, though the similarity is largely superficial. Casual acquaintance on the part of the general public has resulted in the often heard local name of “French mockingbird,” but even this term infers that there is a variation between the two for, as some put it, the prefix “French” implies a more striking appearance and the result is a fancy mockingbird! A. L. Pickens states (MS.) “The Cherokee Indians appear to have confused the mockingbird with the loggerhead under a common name meaning “heads-it-eats” or “head-eaters,” which has given rise to the legend among them that the mockingbird attains its wonderful powers of mimicry by eating the heads (singing parts) of other birds.”
The shrike, however, is a much chunkier bird than the mocker, and the gray is Iflarkedly lighter in shade, much resembling that of the gray kingbird (Tyra’nnu~ dominicc’nsis). The large head, which is the reason for the name loggerhead, is always very noticeable even in silhouette; while the black line through the eve, amounting almost to a mask, is easy to see and contrasts sharply with this lack in the mockingbird.
The entire plumage pattern is very contrasting, the blacks, grays, and whites being distinctly defined and not blending. The tail while at rest appears very slim, and the heavy forepart of the bird suggests a somewhat top-heavy appearance. Unlike the larger northern shrike there is no barring on the breast.
These characters, together with the habit of the bird in selecting such conspicuous perches and its rapid vibratory flight, combine to render it plainly distinctive after a little experience in the field.
Range: Southern Canada to southern Mexico.
Breeding range: Shrikes of the loggerhead group breed north to central northern Washington (Twisp and Riverdale) ; recorded in extreme southern British Columbia (Chilliwack, Osoyoos, Midway, and Edgewood) but no positive evidence of breeding; southcentral Alberta (Edmonton and Camrose) ; southern Saskatchewan (Canton, Quill Lake, and Yorkton); southern Manitoba (Lake St. Martin and Winnipeg) southern Ontario (Emo, Midland, Rutherglen, and Ottawa) ; southern Quebec (Montreal and Karnouraska) and southern New Brunswick (Scotch Lake and St. John). East to New Brunswick (St. John) ; southern Maine (Bangor, ïWaterville, and Saco) ; northwestern Massachusetts (Williamstown) ; western Connecticut (Winchester) ; New Jersey (Elizabeth and Cape May), and the other Atlantic Coast States to southern Florida (homestead). South to southern Florida (Homestead and Fort Myers) the Gulf coast to southern Texas (Galveston, Victoria, San Antonio, and Marathon) ; southern Coahuila (Diamante Pass) ; southwestern Tarnaulipus (G6mez Farms) western Veracruz (Las Vigas) ; to Oaxaca (Tehuantepec). West to Ouxaca (Tehuantepec) ; Guerrero (Chilpancingo) ; Lower California (Cape San Lucas, San Ignacio Lagoon, and San Quintin) ; California (San Diego, the Santa Barbara Islands, Fresno, San Francisco, and Oroville) ; Oregon, east of the Cascades (Tule Lake and Ashland); central Washington (Yakima and Chelan) ; and southwestern British Columbia, possibly (Chilliwack).
Winter range: In winter the races of the loggerhead shrike withdraw somewhat from the northern part of their breeding range. At that season they are found north to northwestern Washington (Blame and Dungeness) ; southern Oregon (Klamath and Tule Lakes) ; western and southern Nevada (Carson and the Charleston Mountains) southwestern Utah (St. George) ; central Arizona (Flagstaff, Fort Verde, and the Salt River Wildlife Refuge) ; southern to central New Mexico (Silver City, Elephant I3utte, and Albuquerque) ; northwestern Texas (Palo Duro Canyon) ; northern Kansas (Stockton, Manhattan, and Lawrence); occasionally to Nebraska (Scotts Bluff and Stapleton) ; central Missouri (Concordia, Columbia, and St. Charles) ; southern Illinois (Mount Cannel) ; southern Kentucky (Russellville) ; Tennessee (Nashville and Johnson City) ; central Virginia (Sweet Briar) ; District of Columbia (Washington) ; and central New Jersey (Princeton) ; rare or accidental north to Wauwatosa, Wis.; Toledo, Ohio; Toronto, Ontario; Rochester, N. Y.; and Concord, N. H.
The range as outlined is divided into several subspecies or geographic races. The typical race, the loggerhead shnike (L. 1. ludovicianus), breeds in the Southeastern States from central Louisiana through southern Alabama and Georgia to southern North Carolina and southward; the migrant shrike (L. 1. migrans) breeds from southeastern Manitoba to northeastern Texas and eastward north of the range of the typical race; the white-rumped shrike (L. 1. e~scubitorides) breeds from central Alberta and southwestern Manitoba south to eastern California, northern Arizona, and central Texas; the Sonora shrike (L. 1. sonoriensis) breeds from the Colorado Desert of California and northwestern Lower California east through southern Arizona and New Mexico, south to northern Sinaloa, Durango, and Chihuahua; the California shrike (L. 1. gambeli) breeds from southern British Columbia (probably), southwestern Montana, and western Wyoming to the Cascades in Washington and Oregon and south to central California, west of the Sierras, and thence along the Pacific coast to about San Diego; the island shrike (L. 1. anthonyi) is resident on the islands of Santa Cruz, Anacapa, Santa Rosa, and Santa Catalina, Calif.; Mearns’s shrike (L. 1. mear’nsi) is resident on the island of San Clemente Island, Calif.; Grinnell’s shrike (L. 1. grinnelli) is resident in northern Lower California south to about latitude 290; Nelson’s shrike (L. 1. ‘nelso’ni) is resident in southern Lower California.
Migration: Only the migrant and white-rumped shrikes are truly migratory, but in the following dates no attempt has been made to divide the races.
Early dates of spring arrival are: Pennsylvania: McKeesport, March 24. New York: Rochester, March 15. Maine: Phillips, March 22. New Brunswick: Chatham, April 6. Quebec: Montreal, March 27. Ohio: Oberlin, March 2. Ontario: London, March 22. Indiana: Notre Dame, March 4. Michigan: Ann Arbor, March 23. Illinois: Rantoul, February 28. Wisconsin: Milwaukee, March 10. Missouri: Columbia, March 11. lowa: Keokuk, March 2. Minnesota: Stillwater, March 18. Kansas: Topeka, March 6. Nebraska: Chadron, February 15. South Dakota: Yankton, March 24. North Dakota: Charlson, March 25. Manitoba: Aweme, March 28. Saskatchewan: Eastend, March 28. Colorado-Colorado Springs, March 2. Wyoming: Douglas, March 5.
Late dates of fall departure are: Wyoming: Laramie, October 15. Colorado-Denver, November 2. Saskatchewan, Indian Head, November 2. Manitoba: Aweme, October 28. North Dakota: Jamestown, December 18. South Dakota: Sioux Falls, November 14. Nebraska: Lincoln, November 19. Kansas: Wichita, November 27. Minnesota: St. Paul, October 26. lowa: Marshalltown, November 14. Missouri: Concordia, November 15. Wisconsin: Unity, November 4. Illinois: Chicago, November 13. Michigan: McMillan, October 26. Indiana: Bloomington, November 30. Ontario-Ottawa, October 18. Ohio: Salem, November 20. New York: Orient, December 9. Pennsylvania: State College, November 17. New Brunswick: Scotch Lake, October 14. Maine: Lewiston, November 24.
The majority of the returns of banded shrikes have been at or near the place of banding. A few recovered at distant points may be quoted. One banded at Carmangay, Alberta, on June 25, 1933, was killed December 22, 1933, at The Grove, Tex., and another banded at the same place on July 10, 1933, was killed on October 0, 1934, at Granger, Tex. One banded at Amenia, N. Dak., on April 7, 1932, was killed on September 8, 1932, at Chriesman, Tex. A bird banded on June 9, 1929, at Whitteinore, Mich., was found on September 5, 1929, at Ramer, Ala. A bird banded as an adult was killed at the same station five years later, being then at least six years old.
Casual records: The loggerhead shrike is reported as of accidental occurrence on Andros Island, Bahamas. A specimen collected at Churchill, Manitoba, on July 1, 1938, has been determined to be a white-rumped slirike; a pair of un(letcrmined race bred near Churchill in 1940.
Egg dates: Arizona: 53 records, March 10 to June 17; 28 records, April 1 to 26, indicating the height of this season.
California: 126 records, February 24 to July 1; 70 records, March 15 to April 15.
Florida: 44 records, February 19 to July 6; 22 records, March 20 to April 11.
Illinois: 90 records, April 4 to July 5; 57 records, April 15 to 30.
New York: 29 records, April 25 to June 28; 18 records, April25 to 29.
Ontario: 17 records, April 5 to June 2; 9 records, May 6 to 9. Texas: 11 records, March 23 to June 4; 5 records, May 4 to 26.
LANIUS LUDOVICIANUS MIGRANS Palmer
Considerable confusion existed in the minds of the earlier writers on American ornithology as to the subspeciflc status of the small shrikes of the loggerhead group that breed east of the Mississippi Valley and north of the Gulf States and the Carolinas. The breeding birds of this northeastern section have been referred by various authors, from the time of Audubon on, to either the southern loggerhead, the western white-rumped, or even rarely to the large northern shrike, L. borealis. I remember very distinctly submitting a shrike that I shot near Cape Vincent in northern New York, during my yout.h, to that careful and eminent ornithologist William Brewster; I was in doubt about it and asked him to identify it; he called it, with some hesitation, a white-rumped shrike, L. 1. excubitorides, but admitted that it was not quite typical. This was, of course, some time before migrans was recognized.
Even as late as 1895 the second edition of the A. 0. U. Check-list gave the breeding range of the loggerhead shrike, L. 1. ludovicianus, as extending northeastward to New England, but restricted excubitorides to breeding west of the eastern border of the Great Plains. The confusion and misunderstandings were finally cleared up by William Palmer (1898), who described and named the migrant shrike, L. 1. migrans, as a distinct subspecies. His historical synopsis gives an interesting account of all the misunderstandings that had prevailed since the days of Wilson and Audubon, to which the reader is referred, as it is too long to be included here. 1-le gives the distinguishing characters of the adult males of the two eastern races as follows: Loggerhead shrike: “Above dark slaty; beneath almost immaculate white; bill large and stout, swollen toward tip; hook large and coarse, gently curved downwards; tail longer than wing.” Migrant shrike: “Above bluish gray; beneath pale slaty; throat white; bill smaller, regularly tapering; hook delicate and sharply bent down. wards; tail shorter than wing.” This wing-to-tail ratio follows the usual rule, that birds having long migration routes have relatively longer wings than those that do not migrate.
He gives the range of the loggerhead shrike as “from middle Louisiana eastward along the Gulf Coast and its indentations; throughout Florida, and eastward into North Carolina. Extending from this range to an indeterminate distance up the valleys, though generally confined bclow the 100-foot contour line. Non-migratory except at its more northern and its higher habitat.” And that of the migrant shrike as “from Maine, Vermont, and Canada to Minnesota; southwards into North Carolina and the Ohio Valley to the Plains. Absent in winter from its more northern and higher habitats and migrating in the autumn toward the Atlantic Coast and into the Carolinas, Tennessee, and lower Mississippi valley. Breeding almost entirely above the 500-foot contour in the valleys, casually up to about 2000 feet, and to within about 50 miles of the coast in Maine. From Canada and the edges of the plains intergrading into excubitorides.”
“From the distribution here given,” says Palmer. “it will be noticed that there is a considerable hiatus between the breeding ranges of these two forms. This is evidently caused by the fact that the interval between the 100-foot and the 500-foot contours is a part of the great coastal plain forest region of the south, a region unsuited to shrikes, and in which they do not breed.”
All shrikes love open country, thinly wooded regions, scrubby country, clearings, meadows, pastures, and thickets along roads and hedges, especially osage-orange hedges. Ora W. Knight (1908) says that, in Maine, “it is largely a bird of civilization, frequenting the hedgerows, wayside trees, telegraph wires and peaks of houses, and I have never seen them at any distance from cultivated lands.” Although the loggerhead shrike is common in the flat pinewoods of Florida, its northern relatives seems to largely avoid pinewoods and dense deciduous woods, though it sometimes breeds in the more open stands of fir trees in the northern part of its range.
Prof. Maurice Brooks sends me the following interesting comment on the distribution of the migrant shrike in West Virginia: “For some reason migrant shrikes are rare in West Virginia west of the Allegheny crests, becoming common or locally abundant in the river valleys of the eastern portion of the State. Whether or not there is any correlation, it is interesting to plot the distribution of this bird and the rainfall within the areas of its presumed rahge. Common in the Middle West where rainfall averages around 30 inches or below, it becomes scarce or absent in the Allegheny foothills of Ohio and western West Virginia, where the precipitation shows a sharp increase to 35 or 40 inches. In the West Virginia regions where rainfall is heavier, 50 or 00 inches, it is, so far as we know, completely absnut as a breeding bird; but to the east, where the Allegheny Mountains throw the valleys into a rain shadow, the bird reappears in good numbers. This may be accidental, but the gap in distribution cannot be accounted for by any known factors of food, temperature, or place to impale victims.”
Territory: Mr. Knight (1908) says: “A pair of birds occupies the same locality year after year, that is to say I have found nests in the same trees or group of trees, and many times on the very same limb from which a nest or nests had been taken in years previously. The eggs also were of the same type so that it xvas evidently the same birds. * * * In one case the male bird was killed and the survivor soon found a mate and had another nest in the same locality within a month. The next season the female was killed, the male shortly found a new mate in the same way and another nest was built, and the eggs laid therein were of a different type. * * * ~ have knowledge of one pair being in the same locality for ten years, and of several other pair for only a year or so less than this.” He does not refer to any attempt at defense of the territory, as observed by Dr. Miller (1931) in the resident California shrike.
Migration: The migrant shrike is well named, as it is more migratory than its southern relative, with which it has been compared. Its migration range is not extensive, for it has been knmvn to spend the winter occasionally as far north as southern New England, where, however, its migrations have been fairly well marked. Evidence seems to indicate that this shrike originally entered New England from the west and that the northward migration in spring is mainly west of the Alleghenies ani~ then eastward into New England. I have never seen it in southeastern Massachusetts in spring and only rarely in fall; but Wendell Taber tells me that he has seen it in eastern Massachusetts on at l~ast four occasions during March, once quite near my home and twice even on Cape Cod. In fall, howev1~, it apparently moves southward, or southeastward, toward the coast and then follows a coastwise route, east of the Alleghenies, to its winter haunts. From the more western portions of its summer range the fall migration seems to move in a more southern, or southwestern, direction to winter haunts as far west as Louisiana and Texas.
Nesting: The nesting habits of the migrant shrike do not differ materially from those of the species elsewhere, except that in some localities it seems to select more often some isolated tree along a highway and often at a considerable height in an exposed situation. In northern New England and in eastern Canada, nests have been found in conifers, firs, spruces, and pines.
Henry Mousley (1918) mentions a nest found near Hatley, Quebec, in a solitary, tall fir tree by the side of a road and not far from his house. The lower branches of the tree had been cut off, and the nest was placed 34 feet from the ground in a dense portion of the tree, so that it could not be seen from the ground. “The foundation of the nest consisted of fir twigs, rootlets, string and that favorite material of most birds here, the stalks and flower heads of the pearly everlasting. The lining was formed of wool, plant down, and a good supply of feathers, and the dimensions were as follows, viz.: outside diameter 6, inside 23/4 inches; outside depth 4’A. inside 21,4 inches.” lie located the second nest of this pair 8 feet up in an apple tree, only 85 yards distant, and suggests that the shrikes may have selected the fir tree because there was no foliage for concealment on the deciduous trees and thickets when the first nest was built. However that may be, there are a number of other records of nests in conifers, up to 20 feet in spruces and firs and down to as low as 4 or 5 feet in stunted spruces. Owen Durfee mentions in his field notes a nest 13 feet from the ground, in plain sight, in an elm tree and another in a pine, both by a roadside near Lancaster, N. H.; and Frederic H. Kennard records in his notes for the same locality a nest 18 feet up in a spruce tree growing by the road in front of a farmhouse.
It must not be inferred from the above records that the migrant shrike does not nest in other situations in this general region, for it has often been found nesting here in apple trees in orchards, in other low trees, and in such thorny bushes and thickets as it. uses elsewhere.
A. Dawes Du Dois has sent me his data for seven nests in Illinois. Four of these were in osage-orange hedges or bushes; one was in an apple tree in an orchard, 15 feet from the ground; one was 12 feet up in a small tree by the side of a little-used lane, with no attempt at concealment; and the lowest nest was only 5 feet from the ground in a wild crab-apple tree in a pasture.
Dr. Miller (1931) lists, in addition to those mentioned above, as among the many types of trees and bushes used as nesting sites by the migrant shrike, oaks, hawthorn bushes, cottonwoods, willows, and wild plum trees, at heights ranging from 4 to 18 feet. Margaret M. Nice (1931) records two nests near Norman, Okia., that were 30 and 40 feet above the ground, respectively; both were in elm trees; the latter seems to be the record height for this subspecies. Dr. Thomas S. Roberts (1932) states that a pair of these shrikes built a nest in an old grackle’s nest and that another pair used an old catbird’s nest, in Minnesota.
Eggs: The migrant shrike lays four to six eggs, rarely seven. The eggs are practically indistinguishable from those of the species elsewhere, which have been well described by Dr. Miller under the California shrike. The measurements of 40 eggs average 24.7 by 18.6 millimeters; the eggs showing the four extremes measure 26.4 by 19.5, 26.3 by 19.9, 23.0 by 18.6, and 24.0 by 17.6 millimeters.
Young: The full account given by Dr. Miller under the California shrike is so satisfactory that it does not seem necessary to say anything here about the incubation of the eggs and the care and development of the young, though some authors have credited the migrant shrike with a shorter period of incubation and a longer altricial period for the young. Probably Dr. Miller’s figures are correct, and doubtless the two races do not differ much in these respects. Apparently two broods are often raised in a season in the north, and probably usually in the south. The male has often been seen feeding the young of the first brood while the female is laying eggs for the second brood.
Plumages: A very full account of all the plumages of all the North American shrikes has been published by Dr. Alden H. Miller (1931), to which the reader is referred, as the descriptions are given in too much detail to be quoted here. Dr. Dwight (1900) describes the juvenal plumage of migrans as follows: “Above, drab-gray, faintly vermiculated and with pale buff edgings; rump slightly paler. Wings and tail black, a white area at the bases of the primaries, the coverts and tertiaries buff tipped, palest on the tertiaries; the outer rectrices largely white, the central ones buff, with terminal mottling. Lores, orbital region and auriculars dull black. Below, dull white on chin, abdomen and crissum, washed on breast and sides with very pale buff or drab, vermiculated with dusky subterminal bands on each feather. Bill and feet dusky becoming black.”
The first winter plumage is acquired by a partial postjuvenal molt, “in September and October. which involves the body plumage, tertiaries, wing coverts and tail, but not the rest of the wings. Similar to previous plumage but grayer above and the vermiculations absent or very indistinct on the breast. Above, plumbeous gray, paler on rump, the posterior scapulars white.
“Wings and tail black except for the brown juvenal primaries, secondaries and primary coverts, the lesser coverts plunibeous, white tips to the new tertiaries and white terminal spots on the lateral rectrices. Below, dull white with dusky vermiculations sometimes faintly indicated. A broad, black bar through the eye.”
He says that in both young and old birds there is a partial prenuptial molt in February and March, “which involves chiefly the chin, throat and head, and a fe~v scattering feathers elsewhere, but neither the wings nor the tail.” All individuals have a complete postnuptial molt, mainly in September, but sometimes beginning in July or August, and sometimes prolonged into October or evemi November.
Food: The migrant shrike eats fewer mice and birds and more insects than the northern shrike does. The northern bird is with us in the States only in winter, when insects are scarce; but the migrant finds insects abundant in its summer home and fairly common in the south in winter. Shrikes are almost omnivorous and will take what animal food is most readily available. The following report by F. II. King (1883) on the contents of stomachs collected iii Wisconsin is interesting as showing the variety of food eaten and the proportions of each: “Of fifteen specimens examined or observed, one had eaten seven moths; three, five caterpillars; two, eleven diptera, among them five crane-flies; nine, eighteen beetles, among them three groundbeetles, three carrion-beetles and two leaf-chafers; five, twenty-two grasshoppers; two, two crickets; three, six May-flies; two, four snails. Two had killed three birds: one, a Canarybird, and one, two Warblens; two, two mice. One of the birds was shot while in the act of killing a meadow mouse (Arvico~a riparia) .”
William Brewster (1938) saw a migrant shrike impale a bank swallow, a bluebird, and a pickerel frog. Others have reported small sparrows as killed by this shrike, as well as shrews, snakes, lizards, and tree frogs. But all the vetebrates eaten form but a small proportion of the food. Invertebrates, mainly insects, form the bulk of the food, of which Orthoptera make up the largest item; but beetles, both beneficial and harmful, cutworms, butterflies, cicadas, wasps, and spiders are also included in the food.
Frank T. Noble (1902) published an interesting account of a migrant shrike that met its match in an attempt to capture a small gartersnake, about 18 inches long. The snake had wound itself around the bird’s neck and had nearly strangled it. Mr. Noble was unable to uncoil the snake until he severed it with a pair of scissors and released the badly frightened bird.
Behavior: The behavior of this species in foraging and impaling its prey has been so fully described by Dr. Miller under the California shrike, that it need not be repeated here~ Mr. Brewster (1938) watched some of these shrikes in their normal behavior and says of their flight: “On leaving their perches, whether the latter were fence posts or telegraph poles, they invariably shot down at a steep angle, as if aiming at some object on the ground and then skimmed off swiftly across the field only a foot or two above the turf, rising and falling in long, graceful but gentle (or shallow) undulations, moving their wings very rapidly at the beginning of each upward curve and then closing them for an instant just as a Woodpecker or Goldfinch does when pursuing its similar ‘galloping’ flight. During the exceedingly rapid beat of the wings their light markings were alternately displayed and concealed, giving a flickering effect as of a small bit of looking-glass flashed in the sunlight.”
This shrike also has a conspicuous hovering flight, hanging suspended in the air on rapidly vibrating wings, like the hovering flight of the sparrow hawk while scanning the ground below in search of prey, its wings serving only to hold it stationary in one spot. While perched, it frequently raises and drops its tail, spreading it during the motion and then closing it and letting it hang..
Voice: So much has been written about the song and other notes of this species under the other subspecies that there are only two items worth mentioning here.
Harold M. Holland writes to me from Galesburg, Ill.: “On a bright, early May morning several years ago, having stopped my car opposite a migrant shrike’s nest in a hedgerow bordering a country road, I became aware of an unfamiliar bird song close by and was surprised to find that this emanated from the shrike occupying the nest. With head slightly raised, it sang for two or three minutes, a low-pitched, pleasing little jumble of notes that lacked the least trace of harshness, as if singing softly to itself, in perfect contentment. Both the unusual ‘song’ and singing from the nest remain lone occurrences in a long acquaintance with this species.”
Saunders and Dale (1933) heard a migrant shrike singing on the wing in Middlesex County, Ontario, on May 24, 1928: “On entering the field we heard a clear whistle that reminded us of a Sandpiper’s note. On tracing this to its source we found the Shrike sitting on a fallen dead apple tree. It flew as we approached and alighted on a thorn bush. The next note resembled that of a Nighthawk. It flew again and as it was on the wing it uttered a rolling call similar to that given by the Bartramian Sandpiper, a bird which, by the way, lives in the same field as the Shrike.”
LANIUS LUDOVICIANUS EXCUBITORIDES Swainson
This is the paler race of the species that is found in the western plains of Canada and the United States, from the eastern border of the Great Plains to the western edge of the Great Basin, and from the plains of the Saskatchewan in Canada to the southwestern desert regions and northern Mexico.
Ridgway (1904) describes it as “similar to L. 1. migrctn8, but gray of upper parts decidedly paler (between slate-gray and no~ 6 gray), changing abruptly to white on upper tail-coverts; white of scapulars more extended (occupying practically the whole of scapular region) and more abruptly contrasted with gray of back; forehead and supraloral region paler gray than crown, sometimes whitish; under parts purer white; size averaging slightly larger.”
Dr. Miller (1931) says of its haunts in general:
This race Is found chiefly in arid, short grass or desert savanna, plains areas. In these regions the original terrane is rarely modified by small farms. In the north the range of this race includes some areas of more luxuriant grassland. The birds forage out over the plains but usually they are to be found near the timber, principally cottonwoods, along water courses. * * In Texas the race is found irregularly in regions where scattered oaks and mesquites occur. Throughout Its summer habitat ercul~itorides encounters comparatively arid conditions with the exception of some northern parts of its range in Canada. Life-zones occupied are Upper and Lower Sonoran, locally Transition in the north.
Between Quill Lake and Prince Albert, in northern Saskatchewan’, I saw a few white-rumped shrikes near the northern limit of their summer range; the country here was rolling, largely open grassland, but with scattered ponds, bogs, and muskegs in the hollows, and with many groves of poplars or aspens on the highlands; it was only thinly settled with villages and small farms.
I have no record of having seen it in southwestern Saskatchewan, though it doubtless occurs there.
Nesting: In southern Arizona we found the white-rumped shrike to be a very coimnon bird and saw a number of their nests, as we drove along the roads; most of the nests were easily seen in the thorny bushes by the roadside, usually not much more than 4 or 5 feet from the ground. Along the road leading to the Chiricahua Mountains we saw several nests in the soapweed yuccas; one of these was a very pretty nest, made of whitish weed stems with white cottony blossoms, giving the nest a soft fluffy appearance; the six eggs in it were so heavily incubated on April 26, 1922, that we did not collect it. But the next day, near the Dragoon Mountains, we took a set of six perfectly fresh eggs; the nest was 8 feet from the ground in a small blackjack oak in open country; it was built on top of an old mockingbird’s nest and was made mainly of weed stalks with the leaf and blossom buds on them, mixed with grasses, straws, and fine twigs; it was lined with finer material of the same kind and with a few feathers. Another set was taken on May 1 from a nest near Hereford that was 4 feet from the ground in a small hackberiy by the roadside. An exceptionally high nest was found on May 27 near Fairbank, in the San Pedro Valley; this was 15 feet above the ground, near the end of a branch of a large willow.
A set of seven eggs in my collection, taken by Fred M. Dille, in Weed County, Cob., came from a nest “in the lower, tangled branches of a scrub willow, 7 feet from the ground.”
Dr. Miller’s (1930) two proposed races~ soflornensis and nevadensis, both of which we have always included within t.he range of excu?itor~ides, seem to have somewhat different preferences as to nesting sites, owing, of course, to the difference in environment. Of the former, the southwestern desert race, he (1931) says: “Mesquite, screw bean, palo verde, smoke-bush, and other desert trees and bushes of similar size afford nesting sites for this race. At Palm Springs, California, I have found several nests fairly well concealed in clumps of mistletoe in mesquite trees ranging in height from seven to fifteen feet above ground. Where broadleaf trees occur these shrikes may make use of such shelter for nesting.” Of the more northern race, he says: “Nesting sites of’nevadensis include willows, cottonwoods, atriplex, Joshua trees, mesquites, Purshia, Lepargyrea argen tea, and Arternis-ja tridentata. Nests may be placed as low as two feet in sagebushes. A nest taken at Lancaster, Los Angeles County, California, was located about five feet from the ground on a hanging limb of a Joshua tree.” For the more northern and eastern race, to which he restricts the name excu~itorides, he says that “principal among the nest sites of this form are the cottonwood and willow trees along the water courses in the Great Plains region.” E. S. Cameron (1908) mentions a Montana nest “in the fork of a box elder” and another “in a cedar.”
Dawson and Bowles (1909) say of the nesting of this shrike in eastern Washington: “The nest is a bulky but usually well-built affair, placed habitually in a sagebush, or a greasewood clump, with wild clematis for third choice. The structure is designed for warmth and comfort, so that, whenever possible, to the thickened walls of plant fibers, cowhair, or sheep’s wool, is added an inner lining of feathers, and these not infrequently curl over the edge so as completely to conceal the nest contents.”
Dr. Jean M. Linsdale (1938) records four Nevada nests in buffaloberry bushes, 2½ to 4 feet above ground, one 3 feet up in a segebush and one in a wormwood only 18 inches from the ground, the lowest I have seen recorded.
Eggs: The white-rumped shrike lays four to seven eggs; six seems to be the commonest number, four uncommon and seven rare. They are practically indistinguishable from the eggs of the species elsewhere, which are so well described under the California shrike. The measurements of 40 eggs average 24.8 by 18.4 millimeters; the eggs showing the four extremes measure 27.4 by 18.3, 26.2 by 19.6, 21.8 by 18.3, and 24.9 by 17.3 millimeters.
Food: In a general way the food of the white-rumped shrike is similar to that of the other races of the species, due allowance being made for what its environment provides. In the southwestern deserts, where reptiles are plentiful, it seems to eat many kinds of lizards and small snakes.
William Lloyd (1887) gives a good idea of its food in western Texas: “It lives on grasshoppers when it can procure them, and in winter, when the weather is severe, takes to carrion. I found one in January, 1884, so gorged from feeding on a dead sheep that it could not fly. In the Davis Mountains it lives in winter on large coleoptera. In spring it occasionally kills birds. I have seen Spi~ella sooiali8 arizon~, Virec belli, Polio ptiia cerulea, and others, amongst its victims, and in summer it has a fancy for nesthings.”
G. F. Knowlton and F. C. Harmston (1944) give a detailed list of the stomach contents of 65 white-rumped shrikes collected in Utah, to which the reader is referred.
Other habits are similar to those of the species elsewhere. It is a migratory subspecies, withdrawing from the more northern portions of its range in the fall and spending the winter in the Southwestern United States and Mexico.
LANIUS LUDOVICIANUS GAMBELI Ridgway
CONTRIBUTED BY ALDEN HOLMES MILLER
Over a large part of North America south of the great transcontinental forests, loggerhead shrikes may be found in open country and broken woodland. But it is chiefly well to the southward, as in California and in Florida, that the species is numerous enough to become a conspicuous element in the bird life. The California loggerhead shrike, Laniws ludoviozanu8 gambeli, westernmost race of the species,
Derived largely from Miller, “Systematic Revision and Natural History of the American Shrikes (La.nius),” 1981 is especially common in the Great Valley of California and in coastal southern California. To the northward in eastern Oregon and Washington and the northern part of the Great Basin it occurs rather sparsely in juniper and sagebrush land. Aggressive, vigorous, and decisive in its actions, and contributing strident bursts of sound and also varied melodic trills to the auditory ensemble, it is likely to be one of a person’s first bird acquaintances in those regions where it flourishes. Shrikes are drawn to roadsides by desirable perches on fences and power lines, and in such places their conspicuous foraging actions and their interesting butchering habits are easily watched, as is also their nesting activity, which centers in isolated clumps of trees or tall bushes. Through the spring and early summer the wheedling cries of large families of hungry young shrikes are an ever-present sound, typical of the parched plains and gently sloping hills of a lowland California countryside.
Loggerhead shrikes hunt by watching from fixed positions, and long unobstructed views are required. Food typically is taken on the ground and is seen from above. These instinctive methods demand that the bird live in the open but where there are good lookout posts. Dense brush and continuous woodland or forest would not permit normal operations. Further than this, these shrikes seem to do best where there is little or but moderate rain and fog, especially in the summer season. Agricultural developments within the range of the California shrike have probably favored this bird by providing trees in open plains areas without diminishing significantly the exposed ground surface where they hunt.
North of California, shrikes are largely migratory, but south of latitude 400 their populations are resident. Migration is never a conspicuous affair in this bird, although on the Colorado Desert California shrikes winter regularly with Sonora loggerhead shrikes, Lanius ludovicianus sonorien8is, which are permanently resident there. Where I have most closely watched California shrikes in Contra Costa County, Calif., and in the Lower San Joaquin Valley, no movements of more than local type have been detected.
Territory: TJnlike many passerine birds, shrikes display territorial behavior throughout the year. Late in slimmer and in fall, resident California shrikes are completely solitary, and males and females defend feeding territories. The annual territorial cycle then may be said to begin at the close of the breeding season early in July when family groups are disintegrating. Typical was the action of an adult male observed on July 3, 1929, at Firebaugh, Fresno County. Two young were pursued seemingly in an endeavor to chase them from the vicinity. The adult sang at frequent intervals and attempted to attack three young captive shrikes that I had in camp. No other adult shrike was permitted to come about the singing posts of this male.
Several other adult shrikes were stationed in adjacent territories at distances of 200 to 400 yards. That one of these birds was the female parent of the young is highly probable. Elsewhere solitary females were collected which were acting in the same manner as this male.
Early in August apparently the same male shrike was observed at Firebaugh. No young were in evidence, and other shrikes repeatedly were chased from the territory with much vigor. The bird was singing as frequently as in July but was in the height of the annual molt. When shot, it proved to have gonads decidedly smaller than is normal for the breeding season. At this same time several l~un4red solitary shrikes were noted in the San Joaquin Valley; not one pair was seen.
By November some few California shrikes have become paired. Members of a pair were seen 30 yards from one another near Firebaugh, and members of another were watched as they amicably occupied perches on fence rails on either side of a small country road. A census on three days late in November revealed only three and a doubtful fourth pair out of 93 individuals watched long enough to determine their status.
Pair formation seems to involve trial chases and begging notes, which doubtless aid in revealing the sex of a bird, or better, in inducing appropriate differentiated response in birds of opposite sex. An apparent example of incipient sexual interest was noted on November 30. A shrike that had been watched for a short time was soon chased violently high into the air by the owner of the area. The chase was accompanied by the sharp note, bzeck, several times repeated, indicative of excitement and usually associated with combat. The intruder was followed to the edge of the territory, whereupon the defender stopped and engaged in a sexual display commonly seen in the breeding season. This consisted of fluttering tbe wings and of begging notes similar to the actions of females during the laying and incubating periods. The bird that had been chased from the territory showed no response, and the bird giving the display ceased and returned to one of its lookout posts. Unfortunately, both individuals were not obtained; the bird that had been driven away proved to be an adult male.
The two birds obviously were not paired at the time. There was some form of sexual excitement in one of them, presumably a female. The chasing perhaps was a sexual flight hut, judged from nuptial activities observed in the spring season, the flight represented a defense of territory. It appears to me that sexual excitation was awakening in the defending bird but was not yet sufficient to overcome the impulse to remain in solitary possession of the feeding territory. At this season a few individuals had yielded to sexual impulses so far as to tolerate association in a territory with a member of the opposite sex. Most of the birds, however, either were in the undecided condition of these two birds or were inactive sexually. It is significant that some pairing activity occurs previous to any perceptible increase in the gonads.
In the vicinity of the Pinole, Contra Costa County, Calif., early in January 1930, I located several single shrikes and studied and mapped their territories. Later, at the time when these shrikes paired and nested, there was no change in the size or limits of the territories, two birds and finally the entire family remaining within the confines of the area once occupied by but one of the parents. In most cases the sex of the original owner of the territory used for nesting was not known with certainty. In one instance a territory was first located when seemingly bitt one bird was present. This bird later proved to be a female, fortunate]y. in this case, mating with a bird sufficiently different in coloration as to be individually distinguishable in the field. The female, when discovered on February 7, I followed about over her territory for some time, and so I was able to outline the area occupied. Had the bird been paired at this time, I am confident from other experiences that the mate would have been seen. By February 10 a male had joined this female and they were constantly close together.
Other solitary birds were found to be joined by mates late in January and still others not until March. Occasionally some minor shifts in the territorial limits may be made when the winter territories are converted into breeding territories, in one observed instance with the seeming purpose of including a desirable nest tree. The complete abandonment of some winter territories is inevitable if pairs are to be formed; disappearances of this kind were noted in a few instances in January.
The size and shape of the territory, whether breeding or feeding, are dependent upon several factors, namely: the floral habitat occupied, whether an open prairie or a moderately wooded area; the concentration of the food supply and the provision of nest sites; the local abundance of the species; and the local associational or physical barriers.
There is a marked difference in sizes of territories in California, and this apparently is correlated with habitat and concomitant variations in food supply. Territories in grassy hills and meadows with scattered oaks, eucalyptus, and lines of willows ranged from 11 to 14 acres in size in Contra Costa County, but in semidesert terrain consisting of much bare ground, widely spaced bushes, and few trees; in Kern County (race Lanius ludoviotanus nevadensis) territories consisted of 25 to 40 acres.
In parts of the northern San Joaquin Valley, where the shrike population is large, nearly every individual’s territory is bounded on all sides by other slirikes. But in the neighborhood of Pinole shrikes hold territories limited by physical and associational barriers. Thus, one pair was bounded to the south and northeast by steep hills, not prohibitive to shrikes, but not so desirable as the flat meadow which they occupied. To the east this pair was limited by the holdings of another pair of shrikes; I witnessed several encounters betxveen them. To the west there was no change in association, no physical barrier, and no other shrikes, yet this pair moved only a limited distance in a westerly direction. Habit and lack of need for further foraging ground apparently had fixed the western boundary.
The defense of a territory is coincident partly with the foraging habits of the bird, which keep it in more or less conspicuous, open places. While a strike is hunting for food it can at the same time see large parts of its territory. Detection of invaders is by sight, less commonly by sound. When not engaged in active feeding, which often is conducted from low perches, the shrike always tends to mount to some high exposed position of observation. Here its ready visibility aided by characteristic form and contrasting markings serves to advertise at considerable distances its possession of the area. This advertisement is aided by song and by the familiar series of 4 to 10 or 12 screeches of progressively diminishing intensity. Loggerhead shrikes are in the greatest degree silent during the nesting season, at which time adult birds have reached the annual minimum in numbers and territorial boundaries are well established. More constant, though less ecstatic, songs and screeches are given late in summer and in autumn when competition in the possession of territories is more severe. The rhythmic summer song then seems certainly to be given for the purpose of warning invaders. A bird in summer or fall perched quietly on a wire or tree top suddenly, and without apparent reason, will break out with its series of violent screeches. No other shrike appears, the bird is not watching any particular prey, and it settles back again into quiet waiting. The screech seems merely an expression of the bird’s presence, an indication of a potential aggressiveness to defend its position.
At Pinole I once witnessed a vigorous attack by the defender. Members of the resident pair were sitting on fence posts about 10 yards apart, one bird, probably the male, singing occasionally. A succession of sharp notes (tree/c) was heard from a third shrike, which had appeared at the edge of the territory about 60 yards distant. This was immediately answered by similar notes from the defending “male.” The invader sang a few trills, then came closer, approaching the “male” of the resident pair and sat on the adjacent fence post. The “female” of the pair was on the opposite side of the defending b’male,~~ which sat facing the invader. The two “males” remained rigidly on guard, neither moving in the slightest. One of them, I could not be sure which, gave a few song trills. After about five minutes both birds suddenly jumped into the air, the defending “male” ca~ne within striking range, and a series of sharp clicks of the bill and a few screeches, low buzzing notes, and staccato vocal notes were heard. The flight of the two continued for a few yards, when the defender returned to the “female,” which had remained quiet and seemingly undisturbed throughout the performance. The repulsed invader towered in a most erratic manner and flew high over the hills at the edge of the valley half a mile away, apparently most intent on departing with rapidity.
In each territory there is usually what may be termed a headquarters. The roosting place, so far as known, is situated here and usually also the nest, if the territory is used for breeding purposes. The headquarters provides good lookout perches, feeding facilities, and some sort of bush or tree for shelter at night. It is occupied during a large part of the day. In many territories, nevertheless, subsidiary headquarters exist. If one wishes to locate a shrike in a known ïterritory, a search in two or three favorable localities usually reveals th~ bird’s presence. Evidently, therefore, all parts of the territory are not used equally, yet territories are defended in their entirety.
The requisite for roosting places seems to be some support above the ground within a screen of overhanging limbs. Roosts are marked by conspicuous fecal deposits. In one instance the nest was built within 6 feet of a roost that had been used for a considerable period previously by the female. The male roosted about 15 feet away in a similar location among dense limbs, the site not being well marked probably owing to his recent arrival on the territory. Arrival at the roost is commonly 35 to 40 minutes after sundown and departure in the morning about half an hour before sunrise.
Courtship: Two aspects of courtship should be recognized. The first type of activity apparently serves to reinforce the pair’s bond. It does not immediately lead to copulation and it normally occurs early in the season. Typical is the following: On January 24, members of a recently mated pair were seen sitting one foot apart on a telephone wire. The birds flew from the wire, one closely following the other. Upon alighting on a fence one of them gave a series of screeches of the usual rhythm but of a peculiar metallic quality, a note found to be associated always with nuptial activities. The two birds then hopped and flitted back and forth from fence wires to fence post in what might be called a mock pursuit. After perching quietly for several minutes on the fence, one bird attempted to alight on the post occupied by the other shrike, whereupon the two again engaged in mock pursuit. Still later one of the birds crouched near the other, fanned its tail, and at the same time tipped its tail upward. This action was followed by more of the metallic screeching, the performer twice flying back and forth 20 feet above the mate, which remained perched on the fence. The flight was erratic and zigzagging with vertical undulations and changes in pace. It is believed that the bird performing this nuptial flight was the male.
This behavior has also been seen in the period following the destruction of a set of eggs. In some instances hovering is interpolated in the nuptial flight. Such hovering is performed at greater height from the ground than that which commonly is seen when shrikes are in pursuit of prey. It is similar to the hovering of excited parents while in defense of small young.
The second type of courtship consists of the feeding of the female by the male. The female postures, flutters the wings, and calls much in the manner of a juvenal shrike. This begins in the final stages of nest-building and continues through the laying and incubating periods. However, the feeding is much more of a routine affair after the set is laid, and one does not then note the extreme posturing and excitement of the laying period. Begging by the female often follows upon her noticing the male in the act of capturing food, whereas at other times her actions seem to arise purely from some internal sexual urge. The female in this type of courtship is the aggressor. The male usually is quiet and nonresponsive to the female and may consistently move away from her advances. If he does respond to her entreaties, it is by rapidly and quietly approaching with food in the bill, which food is snatched from him by the female. If he responds in a more purely sexual manner, it is by a few quickly repeated ecstatic song trills. I have never seen any strutting or display of plumage by the male at this time. Often there is a noticeable increase in the amount of song delivered by him, although this is not given while in close company of the female but from one of the higher perches in the territory.
Between these two phases of courtship there is a period of variable length, when the members of a pair hunt during most of the day, remaining within 50 yards or less of one another but rarely showing any other signs of attachment or of sexual interest. The male usually takes the initiative in moving about from post to post within the territory. At this time neither bird sings to any great degree. Such singing as does occur is performed normally by the male. But the female may sing, although only briefly.
Nesting: The pair, when searching for nest sites, makes an inspection of various densely branched trees and bushes near the headquarters of the territory. Both birds may spend 15 minutes at a time hopping about through thickets of a sort not commonly frequented while feeding.
The nest sites have certain general characteristics. Preference is shown for locations in dense bushes or small thickly grown trees at medium heights, rarely less than 3 feet or more than 25 feet from the ground. Where possible the nests are hidden below the crown of the bush or tree and are placed on limbs that afford ample support for the comparatively heavy structure. The use of old nests as foundations for building new structures frequently is recorded. I have observed this in at least five nests of gem beli.
Nests have been found by me in live oaks, willows, various orchard trees, cypress, sumac, saitbush, blackberry vines, acacias, peppertrees, and eucalyptus trees. The greatest height at which a nest has been noted is 30 feet from the ground in the top of an acacia. Bancroft informs me of the nesting of this race in loose tangles of baling wire about 4 feet high and 6 feet long. Grinnell (1911) records an instance in comparatively barren terrain of nesting between two upright boards of a support for telephone wires.
The materials used in building the nests are extremely varied and dependent on local supply. Shrike nests commonly have an ample substructure of twigs, usually not more than one-quarter of an inch in diameter. Occasionally the nest is a more or less homogeneous cup lacking a base of sticks. Grass is seldom used extensively, but stalks of various annuals are employed, often taking the place of sticks or twigs. The lining ordinarily is heavy, forming a thick felted cup with a wide margin, which frequently projects outward a distance of an inch over the stick framework. The lining includes cottonlike substances principally, with smaller amounts of hair, feathers, rootlets, and bark. The lining is especially variable according to the local supply of materials. In sheep country much use is made of wool.
Wide variation occurs even in nests from the same vicinity. A female of a pair at Pinole built an extremely inferior type of nest early in the spring of 1930. The framework was of small twigs and rootlets, rarely over 2 millimeters in diameter, which basal structure extended not more than 1 inch beyond the narrow rim of the nest cup. The lining was not over one-quarter of an inch in thickness and was composed of willow catkins, hair, and a few strips of bark. Likewise, the nest cup was unusually small, barely 3 inches in diameter and 2 inches deep. A second nest of the same sort was built by this pair, which was only slightly more substantial than the first. The first nest had become dislodged from its precarious position among the small twigs of a willow and had allowed the small young to fall to the ground. In contrast to the efforts of this pair was the series of three nests built by another female, each of which was lined to the extent of nearly an inch in thickness. The cups of these nests were 4 inches across, and the maximum diameter of the entire substructure of one of the nests was 12 inches.
Nests may be situated well braced in crotches of large limbs, against boards or other artificial supports, or among the fine dense twigs of bushes, trees, and vines. The desirability of large limbs as supports seems to be indicated by the fate of three nests I have observed near Pinole. The young in these nests were allowed to fall to the ground or the nests became dangerously tilted as a result of placement among small branches a centimeter or less in diameter.
The female builds the nest with little or no active aid of the male. The difficulty of distinguishing male and female in the field makes it hard to be sure that this is always true. To judge from the actions of pairs in which the sexes of the birds were known, the male usually follows the female while she is gathering material, and he may go with her to the nest but, in my experience, has not been seen to touch the nest or to bring material to the female (see however, Johnson, 1938, with respect to Lanius ludovicianus migrans). He may sit within a foot of the female while she is building. California shrikes are extremely shy while engaged in nest construction and will cease activity when the nest is approached within 60 yards. It is difficult, therefore, to observe the manipulation of material at the site, which is usually well hidden from view. Foraging for material is conducted, for the most part, within a radius of 50 yards of the nest. The greatest distance that I have observed a bird transport substances designed for the nest is 100 yards. Nevertheless, on occasion it is fairly certain that materials are obtained at even greater distances from the nest. One female was seen to go to an old Bullock’s oriole’s nest constructed of hair and tug vigorously at the edge, finally securing small pieces of the rim which it carried directly to its own nest.
Eggs: With gambeli, in the vicinity of San Francisco Bay, sets of seven eggs are as common as those of five, six being the usual number. In San Diego County, Calif., on the other hand, Bancroft states that gambeli lays five or six eggs, usually five. Likewise, I have taken numerous complete sets of five eggs in western Los Angeles County.
The time of laying of first sets ranges from April and early in May in the north to late in March and early in April in the San Diegan district of California. Occasionally sets of eggs are found in February in southern California. Second broods and replacement of destroyed nests may prolong the laying period into the early part of July.
Eggs of the loggerhead shrike vary from dull white to either light neutral gray or buff in ground color. The spots are usually small, the maximum diameter in most eggs being about 21/2 millimeters, but occasionally spots and splotches as large as 61/2 millimeters occur. The sharply defined surface markings vary from neutral gray to various tones of yellowish brown and umber. There also are indistinct light gray spots deposited in layers beneath the surface of the eggshell. Occasionally, fine black scrawlings appear near the large end of the eggs. Spots are more concentrated at the large end but rarely are grouped into pronounced blotches with intervening unpigmented areas. A wreath of spots about the large end rarely is present. Out of 150 eggs of Lanius ludovicianus examined by me, 6 instances of reversal of the color pattern, that is, heavy pigmentation on the small end of the egg, have been noted. Four of these examples were in the same set of eggs.
The measurements of 97 eggs average 24.1 by 18.5 millimeters; extreme measurements are 26.9 and 22.0 for length and 19.4 and 17.3 for width. The average and extreme weights of 100 eggs weighed by Hanna (1924) and myself are: 4.04 gin. (5.7: 3.6).
Incubation: The female alone incubates and begins to cover the eggs usually with the laying of the next to last egg of the set. The incubation period is 16 days.
The female leaves the nest only for short intervals and depends largely upon the male for her supply of food. Usually the female attempts to return and cover the eggs within five minutes after having been flushed from the nest, unless she is an especially wary individual. When settling upon the eggs the shrike usually spends several seconds in moving about rather vigorously, adjusting the clutch so that it will be well covered and included between the two ventral feather tracts on the breast and belly. The incubating bird faces in various directions while on the nest, often turning toward an observer as if better to watch for danger. It has been repeatedly recorded in my notes that eggs in sets are arranged in a definite order in the nest according to the direction in which the bird previously had been facing during incubation. Sets of six eggs usually are arranged in a double row of three, the row paralleling the long axis of the bird’s body. The aligning of the eggs in a double row appears best suited to the brooding of a large sized set by a bird of the narrow proportions of a shrike.
The male feeds the female while she is either on the nest or in the near vicinity of it when she has left incubation to meet the male. The food is not placed in the mouth but, as during the period before incubation, is snatched from the male’s bill and is swallowed at once or, if necessary, first is broken into pieces or impaled. ‘~Vhen fed while incubating, the female either stands up in the bottom of the nest or else remains settled on the eggs and allows the male to approach close enough to enable her to reach the food in his bill. When the pair is not at the nest, the male usually does not approach the female but waits for her to come and take the food from him.
At a nest at Pinole, between 6 and 6: 30 A. i~i., the female was fed five times. On this date, March 31, 1930, sunrise was at 6: 16 A. r~z. Later in the morning the male did not appear at the nest more frequently than every half hour, and on a later date in the afternoon, 45 minutes elapsed without feeding. Occasionally the female may forage for herself within 50 yards of the nest tree; especially is this done if the male is absent. An estimate of the source of the food supply of the incubating female would place responsibility for the provision of at least 80 percent upon the male.
The boldness displayed by the birds when the nest is approached by an observer is highly variable. They are less audacious than when there are young present. Some individuals approach within 2 feet, whereas others do not approach within 100 feet or more. Similarly, some females tolerate an approach while incubating of 1 or 2 feet, others leaving the nest at distances of 50 to 100 feet. Any one bird will vary in its boldness to remain on the nest, depending on the weather conditions, not on the advance of incubation.
Demonstrations at the nest in an endeavor to repulse an intruder include clicking notes, prolonged jaylike notes, schgra-a-a, and to a lesser degree the customary series of intense screeches of progressively diminishing intensity. Snapping of the bill has been observed during a rush toward the observer. In their excitement the tail frequently is fanned, and also flicked sideways or up and down, the feathers of the back and head are elevated, the body is depressed with the head lowered, and the beak often is held open. Such attitudes are alternated with periods of fear when the feathers are adpressed to the body and the head raised accompanying a retreat, or anticipated retreat, to safer distances. The female has been seen suddenly to start begging during the height of her excitement. On other occasioris shrikes have been seen hovering in the air over the nest tree or about the head of the observer. In some pairs the male is the more active defender, while in others the female is the more aggressive of the two. Nevertheless, when there is no major disturbance in progress, the male is usually the one to chase other species of birds from the vicinity of the nest site.
Young: As the young crack open the shells, the greatly dried allantois may stick to the abdomen and cause the lower half of the shell to remain in contact with the bird. Once a female was watched while she sat quietly on the nest on the morning of the day when five of the young hatched. She was seen to stand up suddenly, move to the edge of the nest, and then tug and pull at an empty eggshell, which after three or four efforts was freed from the nest, carried to a distance of about 20 yards, and there dropped.
Young just hatched are bright orange with apricot-yellow bill and fcet; the skin is smooth with few wrinkles and down is nearly lacking, being limited to two single rows of short white neossoptiles on each of the posterior abdominal regions of the ventral tract and a few similar neossoptiles on the elbows.
For at least an hour after hatching the young bird does not beg for food, but soon after commences to raise the head when it is touched or when the nest is jarred. The margin of the open mouth is conspicuously outlined with yellow, but the inside of the mouth is a deep pink with no special markings. Faint thin notes, tsp, tsp, are given by the young as the head is held unsteadily upward.
The actions of the adults during the first day are not especially different from their actions during the incubation period, and there is no increase in their efforts to defend the nest. The female broods nearly as constantly as during incubation. The male procures almost all the food for the family and delivers it to the female, which either passes it on to the young or eats it herself. On several occasions a male was seen to approach the nest and sit beside it while the female was absent. He refrained from sitting on the nest and did not feed the young. The food that is brought to the nest is of such small size as to he, to the observer, invisible within the bill of the adult. Darkcolored parts of insects may be discerned through the skin of the under surfaces of the young. What appeared to be the elytra of small beetles, one-half centimeter in length, were visible in one instance.
On the third day a captive nestling disgorged a pellet 11 millimeters Ifl length containil)g parts of derinestids and the hard muscular portions of the digestive tracts of snails I had fed to it during the morning of the same day. Also included in the pellet was a nearly complete femur, 9 millimeters long, of a small grasshopper that had been fed by the parents at least 24 hours previously. When passing fecal masses the hind quarters are elevated and the head thrust down. The fecal mass is inclosed in a firm mucous envelope, in a position from which it readily may be removed by a parent.
In the wild the parents had difficulty in inducing young to raise their heads, for, several times, the female upon approaching with food waited on the nest edge and, failing in her attempt to feed the young, swallowed the food herself. On another occasion, when the young failed to respond, she gave a faint, low-pitched, burred note, which resulted in an immediate begging for food. Seemingly an auditory stimulus had been necessary to arouse the brood. I then approached the nest, found the birds nonresponsive to touch or to jarring of the nest, and attempted a rough imitation of the nest call that the female had just given. The response was immediate, several heads being raised. Apparently at this age the young are able to receive sufficient food early in the mnornin~ to satisfy their hunger for a period of several hours lasting through the middle of the day.
On the fourth day the male was observed to feed the young for the first time and at the same time was heard to give the nest call similar to that given by the female. The male fed only when the female was absent from the nest. If she was present, food was delivered to her. A large part of the food brought by the parents is now visible in the bill. It was estimated that the female by this time is responsible for the capture of about 40 percent of the food of the family. She still spends much time brooding and occasionally eats -food brought by the male, but rarely begging for it. The young may be left unbrooded for periods of 20 minutes, whereas earlier they were left for but intervals of about 5 minutes even at midday. The anxiety of the female to cover the young is regulated by the temperature. Late in the evening attempts to return to the nest while I was weighing the young were more frequent and bold than at midday when temperatures were as high as 750 F.
Brooding still occupies 50 percent of the time of the female on the sixth day. The male and to some extent the female are much more demonstrative against intruders than previously, coming closcr and making more elaborate attacks upon them. Frequently adults have flown at my head, coming within a foot. It has been reported by several competent observers that at times the parent will even strike the intruder during these attacks. Late in the afternoon at one nest the young were hungry continuously, opening their mouths in response to all manner of stimuli and attempting to swallow fingers or even the wings of other nestlings that, through jostling, happened to be placed inside their open mouths. Nevertheless, the parent fed but three times in 45 minutes.
On the seventh day the brood in one nest was banded. The female, when allowed to return, eyed the nest and picked at the bands, soon lifting one of them up as though extracting a fecal sac. Finding the band attached to the young, she made a more vigorous effort and finally pulled the baud and the leg up above the run of the nest, The next effort dislodged the juvenile, and the female started to leave the nest with the band in her bill and the young dangling beneath. She flew only 6 feet in the direction of the customary depository for fecal masses and then fluttered to the ground. Considerable consternation was registered by both parents; they inspected the juvenile as it lay on the bare ground and screeched and hovered over it. After 10 minutes the female returned to the nest to brood. Fearing that the bird on the ground had been deserted completely, I replaced it in the nest. Subsequently, at each visit to tim nest, the femnale made an effort to remove the bands hut never again proceeded so far as to extract a young bird. Finally, after about 10 such efforts at intervals of 5 or 10 minutes, each effort decreasing in intensity, the bird ceased to pick at the bands. Through repeated trial and error she had come to recognize that this type of foreign material could not be removed successfully from the nest. After the juvenile that had been dropped to the ground was returned to the nest, the female several times left the nest and hovered and hopped about the spot where it had been. The inference would be that the shrike does not sense the number of young in its brood; furthermore, it returns to its young by reason of a memory for location, not necessarily because the young are sighted or heard.
By the twelfth day the young cannot yet stand upright on the metatarsus and hold their heads erect, yet they keep the eyes open and watch objects that move about near them. When the parents are screeching, the young refuse to open their mouths and they lie quiet and low in the nest. After the parents have been absent for. ~eYera1 minutes, they respond to touch with the hunger reaction and seem to lose their fear. The fear attitude is reestablished with the recurrence of screeching and fluttering by the adults. The food call changes from tsp to a husky to/tee/c. The adults now become much warier, and brooding practically ceases. ‘When away from the nest, the female often sits near the male while he foraoes as during the period pre+ious to nest-building. She procures at least half of the food of the young. Occasionally she begs feebly from the male and may receive food, which she eats herself. The male seldom brings food to be delivered to the young by the female, but instead he feeds it directly to them.
By the flfteehth day the young are well feathered, the tips of the remiges forming a continuous flight surface. The weight of juveniles on the sixteenth day nearly reaches that of adults, there being no decline in weight previous to this time although the rate of increase is relatively more gradual during the two or three days preceding. It is likely that in the wild a marked drop in weight follows departure from the nest. In the brood raised in captivity a decline of about 4 or 5 grams a&ompanied the first efforts of the young to l~op about outside of the nest box. At this age the young in the wild squat low in the nest when approached by the observer and, when pulled from the nest, jump and flutter in their efforts to escape. They are belligerent and peck at the hand when captured. Handling of the young, and their screeches, make the adults frantic, and at such times both parents, in their excitement, have been heard giving the begging notes. When the juveniles are left on the ground they hop about giving a note indicated as soreig, which is uttered at intervals of 10 to 20 seconds. The sound appears to be a “location note,” that is, it serves to indicate to the parents the changing locations of the young. The young progress on the ground by hopping, the entire length of the metatarsus touching the ground. In trees and bushes they perch and jump distances of 3 to 6 inches, often falling and fluttering frantically as they cling to twigs and regain their balance. Progression on the ground or in trees is always upward. Young once removed from the nest when replaced usually will not remain but move off through the surrounding brush and, reaching a distance of several feet, sit motionless. In one instance, however, three young returned to a nest from the surrounding tree, a distance of at least 10 feet.
On the twentieth day four of the young at a nest near Pinole still were perched on the much flattened and excrement-stained nest, which for only the preceding four days the parents had failed to keep clean. The young hopped off through the trees while I was yet 6 feet from the nest. This day may be considered as the normal time of final departure from the nest when broods are unmolested.
Feeding still occurs at short intervals. It was estimated that the solitary female parent of one brood brought food 24 times between 9 and 10 A. M. on the twentieth day. Most of the foraging was done within 70 yards of the nest. The six young of this brood all were in the nest tree or in the willow adjacent; they occasionally gave the “location note.” When the female appeared in flight moving toward the nest tree, the typical rhythmic wheedling or begging notes were given simultaneously by many, if not all, of the juveniles. This note had not been heard previous to the twentieth day. This latest and final type of food call of the young is accompanied by a flutter of the wings. Parent birds during this period are shy and usually do not attack intruders unless the young are captured or caused to move from their hiding places in the foliage of trees and bushes.
Between the twenty-sixth and thirty-fifth days the parents continue to feed the young, but at the same time the young are learning to forage for themselves. By the end of the period the juveniles frequently drop to the ground and feed, although they beg and follow their parents when the adults are in sight. The young still tend to stay grouped together but now perch in conspicuous places much of the time. As early as the thirtieth day the young range over the entire territory but make their headquarters near the nest.
Captive birds began drinking water and attempting to bathe on the thirtieth day. When 39 days old a bird sang the usual juvenal, mockingbirdlike song for the first time, the first efforts being, to the human ear, rather grotesque. The clicking vocal notes develop on the twentyfifth day in a feeble, but recognizable, form; impaling of food items begins about the fortieth day.
Second nestings are begun while the adults are still feeding young of the first brood, but not all pairs undertake a second brood. One pair had a new nest with fresh eggs when the young of the first brood were 46 days old.
Plumuages: The natal down is scanty and is white (seep. 167). The juvenal plumage, which is acquired almost entirely before the young leave the nest, is lighter colored and less compact than that of the adult.
Juvenal coloration is as follows: UPPERPARTS: pileum and hind neck smoke gray, each feather with two dusky bars; back olive-gray, each feather usually with narrow smoke-gray tip and a dusky bar; lateral scapulars dull white distally, each with a distinct bar near tip followed by a less distinct bar proximally; the more median scapulars (not the interscapulars) and bases of lateral scapulars light olive-gray; rump and upper tail coverts light drab or clay color, each feather with two dusky bands; frontal tufts gray; bristles black; lores gray; antorbital, suborbital, and auricular regions varying from dull black to hair brown. UNDERPAnTS: chin and throat white; malar region vermiculated wit.h dusky and frequently sparingly tipped with black; breast, sides, and flanks light smoke gray, each feather with two dusky bars; belly and under tail coverts white with dusky spots and bars occasionally occurring on tips. WINGS: primaries dull black, both webs white basally (except outer web of No. 10) but with white more abruptly defined on outer web; primary 5 slightly tipped with light buff, primaries 4,3,2, and 1 with progressively broader dull white tips; secondaries dull black fading basally to gray on margin of inner webs; tips of distal secondaries dull white changing to vinaceous-buff or cinnamon-buff on inner secondaries; greater secondary coverts with clay color tips and median subterminal dots or bars; all middle and upper marginal coverts of forearm similarly tipped and barred with cinnamon-buff. TAIL: four middle rectrices black, with 2.0 millimeter tips of clay color or cinnamon-buff, frequently with a subterminal buff not separate from tip; other rectrices black, extensively but unequally tipped with light buff or white; outer webb of outermost rectrices entirely buff or white.
The first annual plumage is acquired by a partial postjuvenal molt ]fl which the body, plumage, and a variable number, but not all, of the primaries and secondaries are replaced. The white-tipped juvenal primary coverts are retained throughout the first year, these together with the browner juvenal flight feathers serving to distinguish the first-year birds from adults. There is a prenuptial molt of limited extent, involving a few body feathers only. (For detailed description of postjuvenal plumages and the variations in completeness of the postjuvenal molt, see Miller, 1928 and 1931.)
Food: The food of the American shrikes has received special treatment by Judd (1898) and by Beal and McAtee (1912). From an inspection of the reports of stomach contents of birds collected by me and from my own field observations, I am inclined to think that shrikes possess an almost indiscriminate taste for all sorts of animal matter. That is to say, if food properly attracts the attention of a shrike and if it is within its power to obtain it, there are few kinds of animals that are rejected because of unsuitable flavor or consistency. For example, millipeds and beetles that possess odors obnoxious to human beings are eaten by shrikes, although perhaps without relish.
Judd shows that vertebrate food of loggerhead shrikes may amount to as much as 76 percent of the diet during the winter months, but during the remainder of the year it is only 28 percent of the total food taken. However, samples of the stomach contents of gam~beli in winter show it never takes as much as 70 percent of vertebrate food. Both Judd and Beal and McAtee have mentioned the fact that gam~eli seems to take fewer birds and mammals than do the eastern races of the species. This is believed to be due to a more constant supply of insects throughout the year in the range of gambeli in California. Beal and McAtee estimate that vertebrate food during the entire year amounts to only 12 percent in the western races, principally gamleli.
In the San Joaquin Valley of California small rodents occur in the stomachs of shrikes more commonly late in summer than in winter. At this season there is a flux in the populations of Reithrodontomy8 and Perognathus in California. Specimens of ga~nbeZi taken about alfalfa fields, grainfields, and orchards usually have captured no mice. Contrasted with these conditions are those found in areas in the San Joaquin Valley where the sparse native brush is undisturbed, more small rodents having been taken by the shrikes in these localities.
Birds, chiefly small passerines, at no time comprise more than 15 percent of the food.
In regions where reptiles are common, these animals may amount to 7 or 8 percent of the diet. Some of the forms recorded as eaten or impaled are: Uta sp., Soeloporus sp., C’nemido p/torus tessellatus, Phrynosoma, Gerrhonotus, Diadophis, and Thamnophis. Snakes as long as 18 inches may be successfully attacked.
Among the insects, the Orthoptera are variously estimated as constituting 30 percent to 75 percent of the total food. The higher percentages recorded for insects of this order occur at the times of year when grasshoppers increase to plague proportions. Bryant (1912) concluded that grasshoppers at Los Banos, Calif., reached an abundance of 20 to 30 per square yard during a plague in July 1912. At such times California shrikes were found to eat 47 percent of grasshoppers alone. Aside from the many species of grasshoppers and locusts preyed upon by Lanius ludovicianus should be mentioned the Gryllidae and Stenopelmatus. In California, Steno pelmatus is eaten particularly during the rainy season when it may be encountered frequently in fields or pasturelands.
Members of the Coleoptera comprise only 20 percent of the bulk of the food but are represented by a large number of individual animals. Of the 20 percent, the Carabidae contribute 7 percent.
In summarizing the factors that govern the kinds of food eaten by shrikes, I should mention first the factor of the size of prey. Animals too small to compensate for the energy expended by a shrike in procuring them mark the lower limit of size. The maximum size of prey is determined by the limits of the powers of the shrike to overtake and kill large-sized animals. When large animals are available, these perhaps are preferred to smaller animals, since one or two captures with the aid of the impaling reactions may provide food for an entire day. Secondly, in any habitat at any particular season there exists one or more optimum types of prey, that is to say, animals that by reason of their abundance in the habitat and the efficiency witli which they may be captured are most commonly used as food. Obviously, the efficiency with which food is captured in turn depends on a delicately adjusted equilibrium between the many protecting devices on the part of the prey and the detecting powers of the shrikes.
Behavior: The most profitable method of foraging, although not the one commonly observed, is what I have termed active hunting. This activity occurs usually early in the morning and at dusk in the evening. The actions as seen in ga~nbeli consist principally of perching on objects 6 inches to 6 feet above ground where prey clearly may be seen moving within a radius of a few yards. At times the ground or low bushes are resorted to, and the bird hops about in these places in search of animals. The shrikes in moving rapidly from perch to perch fly close to the ground. Instead of waiting indefinitely on a perch until prey is sighted, if food is not secured from a certain post within a minute or two, the bird moves on to another part of its territory. Much or all of the territory may be covered in a short time as a result of these tactics.
Contrasted with active hunting is passive hunting, which is noted commonly during a large part of the day at times other than when adults are engaged in feeding young. It is conducted from relatively high perches that at the same time may serve as territorial lookout posts. Food is captured at distances from the perches of 10 to 150 feet, and there are extended intervals, often 10 to 30 minutes in duration, when no food is taken. The passive form of hunting occurs when digestion and pellet formation are in progress, the results of the early morning active hunting.
A less common method of foraging is the capturing of insects in the air, the birds maneuvering as do kingbirds, although in an awkward fashion. Dragonflies are caught in this manner. The actions consist of darting out into the air at insects as they fly past, the shrike often towering many feet above its perch.
The flight toward prey on or near the ground commonly is a nearly vertical or diagonal plunge either with set wings or, if necessary, accompanied by rapid wing motion. Hovering frequently is observed at the end of the approach flight and is either a searching device or serves to allow the bird better to judge the succeeding stages in the attack. Shrikes are adept at following prey that may fly or run from them. They are aided in this by the short, rapidly moving wings and long tail, which enable them to change rapidly the direction of their flight.
The worrying of prey that is difficult to kill is most persistent. Captive shrikes often spend half an hour at a time in attempting to kill large-sized mice and, failing in their efforts, will worry the mice at intervals during the greater part of a day.
The initial thrust at prey is with the bill. The effective motion is not a pounding or driving action with the end of the beak but a rapid biting motion of the tip of the lower mandible against the tomial tooth of the upper mandible. The killing mechanism, then, is a quick cut or snip of the bill.
After the initial successful thrust with the bill, a series of rapid biting motions follows and sometimes also shaking or pounding of the prey against the ground or perch. In the case of large animals a shrike commonly stands motionless for several seconds, and often minutes, after the animal is dead before further disposing of its catch.
The impaling habit of shrikes is the result of a lack of sufficiently powerful feet to hold the prey while it is being torn to pieces, thorns or crotches being used in order to hold the food while it is being eaten. Once a shrike has killed or injured its prey to the extent that it is incapable of escape, the food is further disposed of in one of two different ways: it is either impaled or else almost immediately eaten. If the food is smaller than about a centimeter in its greatest dimensions, it is swallowed at once or is taken to an elevated feeding or lookout post and there eaten.
Occasionally the feet are used to grasp small prey so as to obtain a fresh hold with the bill. The degree to which the foot is used in this way varies with individual shrikes. When food is held in one foot, the bird does not use that foot to support its weight. II have failed to note any instances of shrikes holding their prey against a perch or against the ground by standing on it, as do jays and hawks. To peck at or tear at food in the foot, as occasionally is done, the shrike seems required by its structure to hold the foot forward of the position normally taken in perching.
I have seen caged birds repeatedly attempt to ingest food that they either had failed to break up by impaling or feared would be taken from them, with the result that they were forced to disgorge. Several times I have seen the foot used to extract objects which were stuck in the mouth. In these instances the foot was not thrust into the mouth but passed along the side of the head, the claws catching hold of projecting parts of the food at the angle of the mouth.
As a rule large objects that must be impaled before being eaten are carried during flight, in the bill, but occasionally in the feet. Esterly (1917) reports the actions of a California shrike as follows:
The shrike flew against a window pane near where I was, and dropped a dead “White-crown.” When the sparrow was picked up again it was seized by the neck, and the shrike flew off with it But before it had gone more than a yard, and while ahout a foot in the air, the shrike released its hold on the neck of the prey, and, without hesitating or altering Its course, caught the sparrow in its feet. The flight was continued for about fifteen yards, and then the shrike dropped to the ground. It started off at once and the same behavior was repeated; the prey was picked up by the neck with the beak and this hold was given up, while flying, for the hawk hold. The substitution is almost instantaneous; the burden does not drop perceptibly and the flight Is continuous and steady.
This observation on behavior, although entirely reliable, must be considered as abnormal, for most shrikes certainly do not handle their prey in this fashion.
With large-sized prey, shrikes resort to special impaling stations within the territory. The variety of impaling devices is great and indicates a generalization of the inherited reaction, permitting individual adaptability in the matter of finding and experimenting with the most effective means for the fixation of food. The first attempts of ]uveniles at ilnpaling have been noted in cage birds. These consist of dragging the food along the perches with a jerking motion, the head held low and the long axis of the bill paralleling the perch. If nails are provided in the perches, the food on encountering these obstacles offers resistance to the bird, which continues to tug and may on occasion thus firmly lodge the food on the nails. Subsequently, small bits are picked from the impaled mass, first gently, but later they are torn loose with great vigor.
Well-known examples of trees and plants used for impaling are orange, yucca, saitbush, and some cactuses. The use of barbed wire is widespread wherever this is available. Ends of broken branches also are used extensively. I have observed a California shrike slip the abdomen of a Stenopelmatus over a broken willow twig one-fourth of an inch in diameter, fitting it on tightly, and then proceed to tear off bits from the open anterior end of the abdomen. My cage birds became accustomed to impaling UI)Ofl the split end of a small broken branch as well as upon nails driven through their perches.
If shrikes are hungry ~vhen large prey is impaled, they eat enough to gorge themselves thoroughly. As much a 7 grams of food may be eaten at a single feeding. If the impaled food amounts to more than this in bulk, the remainder may be left hanging. The shrike returns to the food during succeeding hours and usually eats it to the last morsel. As a storing device, impaling is useful for periods of a day or two only, unless climatic conditions favor the preservation of the animal fcod for longer intervals of time. Impaled objects are comparable to the kills of large predatory mammals, and, so long as they are still edible, the shrike returns to them unless more recent kills occupy its attention. Storage in its true form involves gathering together a considerable quantit.y of food for future use without at the time partaking of it extensively. The object of the American shrikes’ habit of impaling, then, is not truly storage. When concentration of impaled objects does occur it is due to the habitual return of the shrike to a successful impaling station because of the facilities available there for the ready handling of the prey, not because of a desire to store or concentrate food. In inspecting numerous shrike impalings I find that where abundant impaling situations, such as barbedwire fences, are at hand, the unfinished meals of shrikes are distributed along such fences at considerable intervals. Concentrations of im1)alings such as often do occur probably result from a scarcity of impaling facilities in a territory.
A considerable portion of the deserted impalings consists of parts of animals that would seem to be less desirable as food. Jaws of lizards, the hard heads of Steno pelmatus, partly picked bones of mice, and the wings and tails of birds are samples of deserted parts that appear on the average more abundantly than do soft-bodied insects and the flesh of vertebrates. Recent, although deserted, iinpalings do not appear in the same abundance at all times of year in California. During the middle of winter they are rare, and I have iiever found them where young or brooding females were being fed. The season of their greatest abundance is late in summer and in fall.
Voice: Most of the utterances of California shrikes have been mentioned in earlier sections, but they may here be reviewed. The spring song of the male consists of short trills or combinations of clear notes repeated a number of times, yet varied in rhythm, pitch, and quality. For example, each of the separate parts or units of the song may be primarily a trill with three or four distinguishable throbs in it. The quality of t.he trill often is described as liquid, but the trill also contains harsher, burred qualities. Added to this trill are clear, usually sharp, descending or ascending terminal notes. Other songs lack a trill, two or three clear or burred notes, variously accented and pitched, constituting the unit of song. Still other individuals precede a trill by clear notes. The most characteristic features of the California shrike’s song are not pitch or the structure of the unit song of a series but rather the rhythmic repetition of song units and certain general tonal qualities impossible of description or even exact imitation. The units of song are repeated at an average of one every two seconds, but the rhythm may be more ral)id if the song unit is 051)Ccially short.
The feeding territory song of gambeli given late in summer by males and females alike is of the same general construction as the spring song but appears to contain fewer high clear notes and more notes rough in quality and resembling the quality of the harsh screeches or begging notes.
Immature birds give a decidedly different song of a continuous sort, consisting of short screeches, gurgles, tril Is, and clear notes in a succession quite pleasing to the human ear. It is the continuous type of song that has led observers to claim that shrikes imitate other birds. However, I have consistently failed to detect anything in these songs that could definitely be called imitation. Captive juveniles that never had heard songs of other birds or of shrikes uttered primitive songs identical with those given by wild shrikes. Such songs of cage birds are purely instinctive and unlearned.
The screech or call note consists of 4 to 10 or more harsh forceful utterances of diminishing intensity, the first notes slightly higher pitched and shorter than the terminal notes, although pitch is difficult to detect in a sound so thoroughly discordant. A metallic variation of this call note occurs during nuptial displays.
Single notes, schgra-a-a, of a quality less sharp than that of the screeches, variously repeated and resembling the huskier notes of Cyanocitta stelleri, are given by birds while defending their nests. These notes are each longer in duration than a single screech of the call-note series. This type of note also may be given while a loggerhead shrike is worrying prey it cannot readily kill.
Staccato clucking notes are heard during attacks upon invaders or when birds are in a defensive attitude.
The pulsating or begging notes of young and the begging notes of adults are extremely similar, although slight differences in quality may be detected. The tsp and tcheep of young in the nest, fear notes of juveniles, the juvenile’s “location note,” .screig, and the nest call of the parents have earlier been described.
There is but one note given by cage birds that I have failed to hear in the wild and have not seen mentioned in the literature. This is a lowpitched chuckle of weak intensity, which cage birds give when approached and when completely at ease, that is to say, when they are not frightened or in any way excited.
Captive nestlings develop perfectly all the notes of wild shrikes with the exception of the rhythmic types of song.
Enemies: Unfortunately little is known concerning causes of death in California shrikes. These birds are moderately large, aggressive, and well equipped to fight, and it is difficult to understand what happens to the relatively large number of young hatched annually.
Instances of death other than by shooting I have noted have occurred as a result of accident caused by automobiles on roadways. Robert. son (1930) includes in his discussion of death of birds on roadways records of ten California shrikes found dead during one year on the roads hounding a region roughly 10 square miles in an area in southern California under his daily observation. He concludes that the most likely cause of death is collision with automobiles and that death is not caused to any extent by collision with overhead wires or by shooting. Birds probably are struck down by automobiles most commonly early in the morning, for the road surfaces at that time are well baited with insects injured during the night. A shrike while killing prey is likely to be practically oblivious to surrounding dangers, and its powers to spring rapidly into the air are relatively poor.
A shrike at Firebaugh, Calif., after retiring to its roost was heard to give repeated frantic screeches when a horned owl perched on a pole nearby. A barn owl, which approached and perched near the roost shortly after the horned owl had left, provoked no such outburst from the shrike. E. L. Sumner, Jr., has found the remains of shrikes in horned-owl nests. Captive birds are greatly disturbed on being confronted with dead hawks or owls. Similar fear is displayed when hawks, cats, or dogs come near them. Therefore, there is some evidence to indicate that shrike populations experience losses through the feeding activities of large predatory birds and mammals.
The known parasites of shrikes rarely produce death and cannot be considered as contributing importantly to the death rate.
Despite our ignorance concerning the causes of death in shrikes, the life expectation of individuals can be estimated by indirect means. Usually in Lanius ludocicianus first-year birds make up about 50 percent of winter populations. This means that annually half of the breeding population of the preceding season die and are replaced by first-year birds. If we assume that a family group in the spring consists of two adults and six juveniles, the succeeding year would, on the average, result in the death of one of these adults and five of the juveniles. Most of the juveniles would be lost before leaving their parents or during the first summer and autumn. Therefore, the juvenal and immature death rates are high, and the average life expectation of young upon leaving the nest is only about four months. The group of immatures that successfully passes the first winter, later, as breeding birds, constitutes 50 percent of the total breeding population. Theoretically, during each succeeding year this same group must undergo a 50 percent annual reduction by death.
LANIUS LUDOVICIANUS NELSONI Oberholser
The shrikes of this species living in the southern two-thirds of the peninsula of Lower California have been separated by Dr. Oberholser (1918) under the above name. He describes the form as “similar to Lanius ludovicianus gambeli, but bill larger; white terminal areas on outer rectrices much smaller; upper parts averaging darker, though with the upper tail-coverts more conspicuously whitish; lower surface more tinged with grayish, particularly on the posterior portion.” He gives as its distribution: “The southern two-thirds of Lower California, including the adjacent islands, north to 29O30P~ north latitude.”
Grilling Bancroft (1930) says of the haunts of Nelson’s shrike: “There are shrikes near Santa Rosalia. In any small cafion which runs back from the Gulf and which also contains a few trees, three or four, perhaps a breeding pair, of these birds are apt to be found. They nest near San Ignacio Lagoon and amoiig the sand dunes along with the Desert Thrasher. They occupy, intermittently, the terrain between these extremes, but only in associations either of low brush or of isolated trees. On the whole they are to be listed as rare birds.”
Nesting: Bancroft says on this subject: “The breeding season is well under way in March and does not extend beyond April. Either three or four eggs are laid, in bulky nests of tree moss. There is no lining in the cup. The building material, which is the same throughout, is itself soft enough for the eggs.” Dr. Miller (1931) says that, of the three nests found by Mr. Bancroft, “one was in a Joshua tree, one against a bank and covered with a creeping vine, and one in the heart of a growth of tumble weed.” There is a set of four eggs of this shrike in the Charles E. Doe collection, at Gainesville, Fla., that was taken by Mr. Bancroft at a later date, March 30, 1932, at Playa Maria, Lower California. The nest was said to have been of “fine end tops and moss,” and located 3 feet from the ground in a frutilla bush.
J. Stuart Rowley writes to me: “In the Cape region of Lower California, I found this shrike not very abundant and exceedingly ~vary to approach within gun range. One nest was located near Todos Santos on May 22, 1933, containing four fresh eggs,.wliich are smaller than the average size of the northern races. The nest was very well concealed in overhanging vine tangles, but was typically of shrike construction.”
Eggs: The eggs of Nelson’s shrike are apparently like those of other races of this species. The measurements of 18 eggs average 24.9 by 18.3 millimeters; the eggs showing the four extremes measure 26.5 by 18.5,26.0 by 19.5, and 22.8 by 17.1 millimeters.
LANIUS LUDOVICIANUS ANTHONYI Mearns
Two races of this species have been (lescribed from the Santa Barbara Islands, off the coast of southern California, but only the above-named form is recognized in the 1931 Check-list. Dr. Mearns (1898), in naming this subspecies, remarks: “This Shrike is naturally to be compared with Lanius ludovicianus gambeli Ridgway, the form common on the adjacent coast of California, but differs in being very much darker as well as smaller. It is, in fact, darker than the darkest eastern specimens of L. ludovicianus.”
Mr. Ridgway (1904), in comparing it with the eastern bird, calls it the “darkest of all the forms of this species. Similar in coloration to L. 1. ludovicianus, but gray of upper parts still darker (nearly slate color), especially on pileum, and more uniform, the scapulars almost wholly deep gray; white spot at base of primaries much smaller; under parts of body much more strongly tinged with gray, becoming distinctly gray (about No. 6) on sides and flanks; lateral rectrices with much less of white, this extending only about 22 mm. from the tip on inner web of exterior rectrix.”
He restricts this form to Santa Cruz Island, and names a new subspecies from San Clemente Island L. 1. mear’n8i, which he characterizes as “similar to L. 1. antkonyi, but upper tail-coverts abruptly white, more white on scapulars, white spot at base of primaries larger, and under parts of body much less strongly tinged with gray. In white upper tail-coverts, greater extent of white on posterior scapulars and at base of primaries, similar to L. 1. gambeli, but gray of upper parts very much darker (quite as dark as in L. ~. ant hon yi), and with much less of white at base of primaries and on lateral rectrices.”
Ridgway’s new form, meaim-si, was at one time accepted by the A. 0. U. Committee on Nomenclature, but after its validity had been questioned by a number of writers the name was discarded, and it never appeared in the Check-list. The latest authority on this group, Dr. Alden H. Miller (1931), however, recognizes mearn~si as the bird of San Clemente Island, remarking: “Of all the subspecies of L. ludovicianu8, mearnsi is the most isolated race and is among the most sharply characterized subspecies of the species. Although not to be considered as a distinct species, it is surprising to note the doubts that ornithologists have entertained concerning the~ valdity of this race.”
He says of the range of anthonyi:
The Islands of Santa Catalina and Santa Cruz off the coast of southern California comprise most of the range of this subspecies. Santa Rosa Island may. possess a considerable population but thus far fe~v records for this island have appeared. Parts of Santa Cruz Island are forested with live oaks and the Monterey pine. In August 1t122 I found shrikes in the pines and acacias at Prisoner s Harbor and also In the scattered live oaks in the canon lending from this point toward the Interior of the island. Much of the habitat, however, consists of grasslands with small hushes In the cailons. The hills and cafions which the shrikes frequent are often exceedingly precipitous. Likewise, on Santa Catailna Island much of the habitat consists of steep hillsides covered with scrub oak, toyon, Ironwood, and, In places, dense stands of opuntia cactus. * * San Clemente Island Is more arid than those Islands of the Santa Barbara group on which anthonyi occurs.”
Nesting: Dr. Joseph Grinnell (1897) found a shrike’s nest on April 2, 1897, on San Clemente Island: “The nest was in a small bush growing out from the side of a cafion, and was composed mostly of sheep wool, with an admixture of weed stems and grasses. Five slightly incubated eggs constituted the set. They are not different from eggs of true L. 1. gambeli of the mainland.”
Dawson (1923) records two nests found on Santa Cruz Island, near Prisoners harbor, one 6 feet up in an acacia tree and the other in a pollard willow. The first nest contained six eggs and the second held five; in both cases there were two distinct types of eggs in the nest, with three shrikes in attendance. Dr. Miller (1931) says that “Mailhard (1899, p. 42) found two nests on the same island, one placed in a brush pile, the other in a gum (eucalyptus) tree.”
Eggs: The four, five, or six eggs laid by the island shrike are apparently indistinguishable from those of the bird of the mainland. The measurements of 30 eggs average 25.0 by 17.5 millimeters; the eggs showing the four extremes measure 26.1 by 18.3, 24.9 by 19.7, and 24.4 by 13.2 millimeters.
Behavior: One of the most prominent characteristics of the island shrike seems to be its shyness or its wildness. Dr. r~Iiearns (1898) writes:
All who have seen it regard It as one of the wildest of birds. On his visits to San Clemente, in 1888 and 18S9, Mr. Townsend was unable to obtain a specimen. In 1894, Mr. Anthony and myself procnred a single one: with difficulty, although Shrikes were seen daily. At night, when we went out to shoot bats, Shrikes would dash about us, uttering loud, harsh screams, differing from the voices of any Shrikes I have heard elsewhere. In the daytime they never permitted us to come within range of them.
Dr. Grinnell (1897) found the birds on San Clemente equally shy: “This bird was without question the shyest and hardest to be secured of any on the island. Indeed it was as shy as any hawk I ever saw. It was tolerably common; that is, two or three could be generally seen during an hour’s walk. There was a pair in the neighborhood of the windmill where we were camping, and nearly every morning a little after daybreak the male would perch either on the windmill or on the topmost twig of a brush pile on the opposite aide of the ravine, and utter its defiant shrike notes. The rustle of the tent door or the click of a gun lock, however, was sufficient to send him up over the ridge, not to appear again for hours.”