A far northern nester, the Northern Shrike moves well south during the winter, and in some years move farther than others. Larger than the Loggerhead Shrike, the Northern Shrike consumes more vertebrate prey and fewer insects than its smaller relative.
Northern Shrikes are very aggressive in defending a hunting area, even in the winter. Other species are often chased away in addition to other Northern Shrikes. Even larger birds such as kestrels, hawks, and owls may be chased.
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Description of the Northern Shrike
The Northern Shrike has a gray crown and upperparts, black wings with a white patch most obvious in flight, a black tail with white outer tail tips, a wide black line or mask through the eye, and a long, black, hooked bill.
Seasonal change in appearance
Juveniles are brownish above and have a brownish scaled appearance to the underparts.
Northern Shrikes are found in open country with scattered trees and fence posts.
Northern Shrikes eat birds, rodents, and large insects.
Northern Shrikes watch for prey from a perch site, and then pursue and capture it, sometimes impaling it on a thorn or barbed wire fence.
Northern Shrikes breed in Canada and Alaska and winter in much of the northern and western U.S. The population may be stable, but is not well monitored.
Shrikes are capable of catching prey nearly as large as themselves, despite the lack of powerful talons wielded by raptors.
The Northern Shrike’s scientific name means “butcher watchman”, a reference to both its foraging behavior and its predatory ability.
The song is a feeble series of repeated phrases.
- The Loggerhead Shrike is smaller, darker gray, with a shorter bill and wider black mask.
The nest is a bulky cup of twigs, grass, and other plant materials and is often lined with feathers or hair. It is usually placed low in a tree or shrub.
Number: Usually lay 4-7 eggs.
Color: Gray or greenish with darker markings.
Incubation and fledging:
The young hatch at about 15-17 days, and leave the nest in another 19-20 days, though continuing to associate with the adults for some time.
Bent Life History of the Northern 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 Northern Shrike – the common name and sub-species reflect the nomenclature in use at the time the description was written.
LANIUS BOREALIS BOREALIS Vieillot
The great northern shrike, or butcherbird, is known to most of us only as a rather uncommon winter visitor throughout the northern half of the United States, where we see it as a solitary sentinel perched on the top of a tree, looking for seine luckless small bird, or hovering over an open field, ready to pounce on the timid little mouse as it threads his winter runway. Either bird or mouse is to be added to his larder, impaled on a nearby thorn or crotch, as the butcher hangs his meat; hence the appropriate name of butcherbird (p1. 15).
Few of us have been favored to see it in its summer home, for it breeds as far north as the spruce forests extend and comes south only when scarcity of food compels it to do so. We found it fairly common all along the coast of Labrador, from Hopedale to Nain and Okkak, wherever there was any considerable growth of fair-sized spruces. According to Lucien M. Turner (MS.), it was not very common at Fort Chimo, Ungava. Westward from Hudson Bay it begins to intergrade with the northwestern subspecies (invictus).
Nesting: T here are three sets of eggs of the northern shrike in my collection, all taken by the Rev. W. IV. Perrett at Hopedale, Labrador. They were all placed in spruce trees, about 12 feet from the ground, nicely hidden by the branches, and all were very bulky affairs. The first nest was discovered by seeing the male bird carrying food to the female while she was sitting on the nest; the nest contained only two eggs, on June 7, 1915, but the data slip says “incubation just begun”; the nest was made mainly of twigs, grass, feathers, rags, and deer hair.
This same pair of birds built another nest in the same patch of woods, about 150 yards from the first nest, fr6m which he took a set of four fresh eggs on June 17, 1915; these birds had built their new nest in seven days; as there were no eggs in it on the 13th, the bird must have laid an egg each day. The third set of six fresh eggs was taken on June 3, 1918. The three nests were all made of similar materials.
There is another set of six eggs of this shrike in the Carnegie Museum, taken by Mr. Perrett in the same locality on June 17, 1918, for which W. E. Clyde Todd has sent me the data. The nest was constructed of similar materials and was located 8 feet from the ground in a spruce tree. This was evidently the second set from the same pair of birds from which my set of six eggs was taken on June 3. This second nest was located about 400 yards from the first; it had been built and the six eggs laid in the short time that intervened.
Eggs: The usual set for the northern shrike may consist of two to nine eggs, though I believe that any sets of less than four are incomplete and that the large number of nine is unusual; probably four to six are the usual numbers. What few eggs of this species I have seen are ovate or rounded-ovate and nearly lusterless. The ground color is grayish white or greenish white, and they are usually heavily spotted or blotched over the entire surface, seldom having the spots concentrated at one end, with olive-brown, dull olive, or pale dull brown, and with underlying spots and blotches of different pale shades of Quaker drab or lavender. The measurements of 31 eggs average 26.7 by 19.5 millimeters; the eggs showing the four extremes measure 28.0 by 20.0, 27.0 by 20.5, and 25.9 by 18.5 millimeters.
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; his descriptions are given in too much detail to be quoted here. Dr. Dwight (1900) describes the juvenal plumage of a specimen taken in Labrador, as follows: “Above, brownish mouse-gray with indistinct vermiculations, especially on the rump. Wings black, a white area at bases of primaries; the coverts, tertiaries and secondaries edged with wood-brown, or pale cinnamon mottled from irregular extension of the color, and similar tipping on the rectrices which are black, the lateral ones largely white. Below mouse-gray, nearly white on mid-abdomen, indistinctly vermiculated, more marked on sides and crissum. Bar through eye dull clovebrown; lores grayish.”
A partial postjuvenal molt occurs, mainly in July and August, which involves the contour plumage and the wing coverts, but not the rest of the wings or the tail, producing a first whiter plumage, which Dr. Dwight (1900) describes as follows: “Above, French gray washed with brownish gray, the rump grayish white. Lesser coverts cinereous gray, the median black, the retained greater coverts dull black buff tipped. Below grayish white with indistinct dusky vermiculations except on the chin, abdomen and crissum. Tail black, the three outer rectrices with much white. Lores grayish. Bar through eye dusky.”
He says that the first nuptial plumage is “acquired by a partial prenuptial moult in March which involves the anterior part of the head, chin and throat. A whiter chin and black lores are acquired, young and old becoming practically indistinguishable. A good deal of the veriniculation is lost by wear of the feather edges.” Dr. Miller (1931) says that this molt, “as far as known, occurs in March and April and is associated with the change of the bill from brown to black.” And he adds that the young bird frequently loses, at this molt, “large, but often irregular, areas of the brown first fall plumage from the back, head, and shoulders.”
Dr. Dwight (1900) says that the adult winter plumage is acquired by a complete postnuptial molt, which Dr. Miller (1931) says occurs in July and August, “perhaps also early September.” According to Dr. Dwight, this adult winter plumage differs from the first winter plumage “in having a white wing band on the greater coverts, the tertiaries and secondaries with white edgings, the wings and tail jetblack, including all the coverts. The back is grayer without the brownish tint of the young bird.”
The above remarks apply to the male; in the female the sequence of molts and plumages is the same. Ridgway (1904) says that the young female, in first winter plumage, is “similar to the young male of corresponding season but browner, the color of upper parts approaching isabella color, the scapulars, lower rump, and upper tail-coverts washed with cinnamon-buff, under parts more or less washed with the same, especially on sides and flanks, greater wing-coverts edged with the same, and white at tips of secondaries and rectrices more or less buffy.” In the adult female, the gray of the upper parts is less pure than in the male, darker and more or less tinged with olive, the black of the wings and tail is duller, and the white markings are more restricted.
Food: Dr. Sylvester D. Judd (1898) writes of the food of the northern shrike: “During its winter sojourn it renders a threefold service by killing grasshoppers, English sparrows, and mice. The birds and mice together amount to 60 percent, and insects to 40 percent, of the food from October to April. Grasshoppers constitute one-fourth of the food, and are equal to twice the combined amounts of beetles and caterpillars. * * * In the stomachs of the 67 butcherbirds examined 28 species of seed-eating birds were found. Of these 3 were tree sparrows, 5 juncos, and 7 English sparrows; the others could not be determined with certainty.”
In the early days of the English sparrow in this country, while they were being protected, northern shrikes became so abundant on Boston Common that men were employed to shoot them, lest they destroy the sparrows. In this connection, Dr. Judd remarks: “It is to be hoped that in other cities this enemy of the sparrow will be protected instead of persecuted. If there were 6 butcherbirds in each of 20 New England cities, and each butcherbird killed 1 sparrow a day for the three winter months, the result would be a removal of 10,800 sparrows. Since two sparrows could raise under favorable conditions four broods of 5 each, the increase would be tenfold, so that those destroyed by the butcherbirds, if allowed to live, would have amounted at the end of the first year to 118,800, and at the end of the second year to 1,306,800 individuals.”
In addition to the three named above, he lists the following birds that this shrike has been known to kill: Chickadee, snow bunting, downy woodpecker, vireo, kinglet, field sparrow, goldfinch, siskin, myrtle warbler, mourning dove, cardinal, longspur, and horned lark.
Among mammals, meadow mice (Microtus) seem to be the most frequent victims, but Judd also lists the white-footed mouse (Peromysails) and the harvest mouse (Reithrodontomys). He continues:
Carrion is sometimes eaten. Prof. F. E. L. Deal, while at Ames, Iowa, In January, 1880, saw a butcherbird fly over the brown frozen prairie to a carcass of a cow, where it lit on one of the ribs and greedily tore off shreds of the flesh.
Active insects are much more liable than sluggish ones to fall victims to the butcherbird, because objects which at rest can not he discriminated are Instantly seen when moving. Thus it happens that flying grasshoppers and running beetles form a large proportion of the food of this bird. Grasshoppers and crickets (Orthoptera), which are eaten during overy month from October to April, form 24 percent of the total volume of food, and for October and November together these Insect pests form more than half of the food. Compared with Orthoptera, the beetles (Coleoptera) eaten are of minor importance, amounting to only 6 percent of the food. More than half of these beetles belong to the family Carabidae, the members of which prey upon insect pests. Caterpillars were contained in one fifth of the stomachs examined, and during the months of January and February amount to 8 percent of the volume of the stomach contents. Dr. A. K. Fisher collected in March two stomachs that were full of caterpillars. Even the bristly Isabella caterpillar Is eaten, an object apparently as edible as a chestnut bur. Cutworms were found in several Instances, but moths were seldom met with. Ants, wasps, flies, and thousand legs are sometimes eaten, and spiders constitute 3 percent of the food; but bugs (Hemip tore) were not detected during our laboratory investigations, though a cicada supposed to have been impaled by a shrike was found by Mrs. Musick, at Mount Carmel, Mo. * * * The present Investigation shows that beneficial birds form less than onefourth of the food of the butcherbird. It also shows that the butcherbird, in addition to being an enemy of mice, is a potent cheek on the English sparrow, and on several insect pests. One-fourth of its food Is mice; another fourth grasshoppers; a third fourth consists of native sparrows and predaceous beetles and spiders, while the remainder is made up of English sparrows and species of Insects, most of which are noxious.
The amount of insect food taken by the northern shrike, as stated above, seems surprising. The stomachs examined must have ken taken largely in the southern extremes of its winter range, or in fall or spring, for the shr4e would not be likely to find flying or crawling insects in New England or in the Northern States in the dead of winter; but grasshoppers are often available in New England in October, and even in some Novembers, and other insects in March.
Dr. Miller (1931) adds the following birds to the list mentioned above, as taken by the species, including both subspecies: Hairy woodpecker, phoebe, white-winged crossbill, redpoll, titmouse, bush tit, and robin. Charles B. Floyd (1928) adds song, white-throated, and fox sparrows and the starling to the list of victims and says:
Several reports are at hand of unsuccessful attempts to capture White-breasted Nuthatches, English Sparrows, Downy Woodpeckers, etc. In several cases where a Shrike pursued Nuthatches, the latter escaped capture by entering a hole in a tree or a nesting-box. The Downy Woodpecker often out-manoeuvred its pursuer by constantly turning and dodging in the air rather than by flying away in an attempt to escape by speed, as do almost all the other small birds. Twice this winter I have personally watched a Shrike attempt to capture a Downy Woodpecker from above. Each time that the Shrike swooped to strike the bird, the Downy turned quickly in the air at a sharp angle, the Shrike overshooting its mark. It their turned with much more effort than the woodpecker, and again took up the pursuit. So long as they were in sight: and I saw the Shrike swoop a number of times: the Woodpecker continued on its way apparently unafraid, and dodged each attack with ease.
Several observers have seen shrikes chasing blue jays or found one of the jays impaled in the usual shrike fashion. Ora W. Knight (1908) adds the pine grosbeak to the list of the shrike’s victims. William Brewster (1936) gives the following account of a shrike in pursuit of a brown creeper:
When I first saw him, he was in hot pursuit of one of the Brown Creepers and both birds were about over the middle of the river arid scarce a yard apart. The Creeper made straight for the big elm which stands at the eastern end of the bridge. When lie reached it, the Shrike’s bill was within six inches of his tail, but he nevertheless escaped; for an instant after the two birds doubled around behind the trunk the Shrike rose to the topmost spray of the elm, where he sat for a minute or more, gazing intently downward, evidently watching for the Creeper. The latter, no doubt, had flattened himself against the bark after the usual practice of his kind when badly frightened and he had the nerve and good sense to remain perfectly still for at least ten minutes. My eyes were no better than the Shrike’s, for it was in vain that I scanned the trunk over and over with the greatest care. Feeling sure, however, that the Creeper was really there, I waited patiently until at the end of the period just named he began running up the trunk, starting at the very point where I had seen him disappear. It was one of the prettiest demonstrations of the effectiveness of protective coloration thai: I have ever witnessed in the same publication, he vividly describes the capture and killing of a field mouse:
As I watched a Shrike it flew from the topmost spray of a small maple into some alders and alighted on a horizontal stem about a foot above the level of surrounding snow but directly beneath; as I afterwards found, the snow had thawed quite down to the ground, leaving a trench about two feet deep by three or four inches wide, into which the Shrike, after peering intently for a moment, suddenly dropped with fiutlering wings and wide opened tail.
Within a second or less it reappeared, dragging out a Field Mouse of the largest size. The moment It got the Mouse fairly out on the level surface of the snow it dropped it apparently to get a fresh hold (as nearly as I could make out it had held it up to this time by about the middle of the back). The Mouse, instead of attempting to regain its run way, as I expected it would do, instantly turned on its assailant and with surprising fierceness and agility sprang directly at Its bead many times in succession, actually driving it backward several feet although the Shrike faced its attacks with admirable steadiness and coolness and by a succession of vigorous and well aimed blows prevented the Mouse from closing in.
At length the Mouse seemed to lose heart and, turning, tried to escape. This sealed its fate for at the end of the second leap it was overtaken by the Shrike, who caught It by the back of the neck and began to worry it precisely as a Terrier worries a Rat, shaking it viciously from side to side, at the same time dragging It about over the snow which, as I could plainly see through my glass (I was standing within ten yards of the spot) was now freely stained with blood. I could also see the Shrike’s mandible work with a vigorous, biting motion, especially when it stopped the shaking to rest for a moment. When It finally let go its hold, the Mouse was evidently dead.
After the shrike had carried off the mouse in its claws, partly eaten it and hung it in a fork, Mr. Brewster examined the mouse.
The Shrike had not touched any part of the body but the skin had been torn away from the entire neck and the muscles and other soft tissues were almost entirely gone from the shoulders and sternum to the base of the skull. The body was untouched and the skull showed no signs of injury, but the cheek muscles had been eaten pretty cleanly away as had also the entire throat with the tongue. Both eyes were whole and in their sockets. This examination confirmed the conviction which I formed while watching the Shrike and Mouse struggling together, viz, that the bird killed the Mouse partly by throttling: that is by choking and shaking it and partly (perhaps chiefly) by cutting open its neck on one side. No attempt was made to stun the Mouse by striking at its skull, such blows as I saw delivered being evidently intended merely to keep the Mouse at bay until the Shrike could close with it and get it by the neck as it finally did.
Mr. Brewster’s close observation and careful description shows what is perhaps the shrike’s usual method of killing rodents, and I can find very little evidence to the contrary, but Mr. Forbush (1929) says that John Muir “saw a shrike go down into a gopher hole and drive out half a dozen young gophers, and hovering over on& after another as they ran, it killed them all by blows delivered from its powerful bill on the back of each one’s head.”
Dr. IV. S. Strode (1889) tells the following story of a mouse-hunting shrike:
Not long since a young farmer invited me out to his field near town where he was husking shock corn, to see a ‘Mouse Hawk,” as he called it, catch mice. On coming to where he xvas at work I looked about for the Shrike but did not see it until he pointed to a tree two hundred yards away where it sat on the topmost twig. Pretty soon a mouse ran from the shock, when it came almost with the rapidity of an arrow, and seizing the mouse in its bill flew away with It to the woods across the river, but in a short time it was back again at Its perch on the tree where it did not remain long until another mouse ran out from the shock. In order to test the bird’s boldness I pursued this mouse, but undaunted it flew almost between my feet and secured it, and apparently not liking Its hold it alighted a few rods away and hammered the mouse on the frozen ground, and then tossing it in the air caught it by the throat as it came dawn. He then again flew off to the woods. This proceeding the farmer assured me would be repeated many times in the course of the day, and that every mouse would be carried to the strip of woods just over the river. Suhsequently a chopper told me that be had found a honey locust tree in this woods that had mice stuck all over it on the thorns.
The northern shrike has two principal methods of hunting, watchful waiting and active pursuit. The former method is the one usually employed, as in the above accounts, in securing mice; the bird perches patiently and motionless on some commanding tree, post, or wire, ready to pounce suddenly on its unsuspecting quarry; mice may be secured also by hovering over their runways in the fields and meadows. Grasshoppers, crickets, and other moving insects may be taken by watching for them, hovering over the fields, or by active pursuit on the ground, though I have not seen the latter method mentioned. But birds must be caught by active pursuit in the air or by chasing them through the trees and bushes; in the latter case the birds escape more often than they are caught by seeking the shelter of dense growth where the shrike is less adept in penetrating the thickets and dodging through the tangles of branches and twigs; cedars and other dense evergreens offer excellent havens of refuge for small birds. Small birds easily recognize the difference between a shrike and some other harmless bird, and immediately “freeze” in their tracks, or seek shelter in the nearest dense cover.
The shrike is a fairly swift flier, but is often not able to catch a smaller bird in a straightaway flight, especially if it resorts to dodging, at which the heavier bird is less adept. The shrike’s usual method is to rise above its victim and dive down upon it, felling it to the ground with a stunning blow from its powerful beak, which often proves fatal by breaking the little bird’s neck or its back. The shrike follows it to the ground immediately and, if necessary, kills the bird with a blow at the base of the skull or by biting through the vertebrae of the neck. Small birds often escape from such attacks by mounting higher and higher in the air, so that the shrike cannot get above them, and then suddenly darting downward into thick cover.
Having killed its bird, the shrike seizes it by the neck or shoulders in either its bill or its claws, or both, and flies away with it. Mr. Floyd (1928) made a number of inquiries on this point and received replies from 23 observers, 13 of whom reported that the prey is carried in the bill, I said in the claws, and 3 had seen both bill and claws used. By some one of these methods the bird is carried to the shrike’s larder and impaled on a thorn or a sharp stub on some tree or bush, on the barb of a barbed-wire fence, or some other similar point; often the bird is hung by its neck in the acute angle of a fork in a branch or twig. Mice are hung up in the same way, to be immediately devoured or saved for future reference. The feet and claws of the shrike are evidently not strong enough to hold the quarry firmly while it is being torn apart, and some additional support is desirable; hence this characteristic habit. If the shrike is really hungry, its prey is gulped down almost entirely, flesh, feathers, for, and most of the bones, only a few of the larger feathers and bones being discarded. These indigestible portions of the food are disgorged later in the form of pellets, which are often found where shrikes have been feeding. Edwin A. Mason sends me the following description of a pellet that he took from a birdbanding trap where a shrike had been feeding on a junco: “Including a 10-mm. tip, or tail, the pellet was 40 mm. long and 10 mm. thick, consisting largely of matted feathers; scattered through the mass could be seen small pieces of bone, some identifiable as from the skull, one tarsus with foot attached, and one fragment of bone obviously from the main body skeletal structure.” A very brief period of time had elapsed between the ingestion and the regurgitation of the indigestible material.
Mr. Floyd (1928) mentions “several pellets which measured from half an inch long to one and one-eighth inches. They averaged threeeighths of an inch in diameter.”
The northern shrike often kills more mice or birds than it can use at once, to many of which it never returns, and these are left to dry or rot. It has been known repeatedly to enter a bird-banding trap, kill all the birds in it, and not eat any of them. It sometimes dashes into a flock of redpolls or goldflnches, knocking out several of them, perhaps for the mere sport of killing them. Mr. Floyd (1928) writes: “A shrike that was seen to enter an electric-car barn in pursuit of an English Sparrow killed all the Sparrows in the barn, without thought of itself or pausing to eat any of its victims.~~ In captivity it will eat almost any kind of raw meat, will kill living birds and eat them, or eat dead birds or mice, though it seems to prefer mice to any other food. It will come to a feeding station to eat suet or hamburg steak, even when live birds are in the vicinity. Dr. Charles W. Townsend (1933) says: “On a warm March day I watched a Shrike fly-catching from the top of a tree. lIe pursued a large bee and missed it, but by a quick turn he caught it. * * * Once I saw two on March 9 hovering about the dry thatch-grass cast up on the beach, apparently picking up flies and spiders.”
Behavior: Much of the behavior of the northern shrike has been referred to above. The outstanding traits of this bloodthirsty rascal are boldness, fierceness, and savagery in its fearless and relentless pursuit of its prey, utterly regardless of obstacles or the presence of man. Nuttall’s (1832) historic account illustrates its audacity:
Mr. 3. Brown, of Cambridge, informs me that one of these birds bad the boldness to attack two Canaries in a cage, suspended one fine winter’s day at the window. The poor songsters in their fears fluttered to the side of the cage, and one of them thrust his head through the bars of his prison; at this instant the wily Butcher tore off Its head, and left the body dead in the cage. * * * On another occasion, while a Mr. Lock in this vicinity was engaged In fowling, he wounded a Robin, who flew a little distance and descended to the ground; be soon heard the disabled bird uttering unusual cries, and on approaching found him in the grasp of the Shrike.
He snatched up the bird from its devourer; but having tasted blood, it still followed, as if determined not to relinquish its proposed prey, and only desisted from the quest oa receiving a mortal wound.
Dr. Brewer (Baird, Brewer, and Ridgway, 1874) writes:
Its bold audacity and perseverance are quite remarkable, and are often displayed, in the fall, in the manner in which it will enter an apartment through an open window and attack a Canary, even in the presence of members of the family. * * * In one instance the writer was sitting at a closed window reading, with a Canary hanging above him. Suddenly there was a severe blow struck at the pane of glass near the cage, and the frightened Canary uttered cries of alarm and fell to the bottom of Its cage. The cause was soon explained. A Shrike had dashed upon the bird, unconscious of the intervening glass, and was stretched upon the snow under the window, stunned by the blow. He revived when taken up, and lived several days, was sullen, but tame, and utterly devoid of fear.
Mr. Floyd (1928) writes: “Northern Shrikes are particularly destructive and annoying about a feeding or banding station. Their audacity is well known. They do not hesitate to seize a bird newly banded when it flies from the bander’s hand, and they enter a trap, barn, room, or hen-house with absolute unconcern when birds or mice are seen there. In the trap they kill all the birds there before considering how they may escape or pausing to eat.” He says that, “when intent upon the capture of its next meal, the Shrike loses all sense of fear of man,” and tells how Mrs. Richard B. harding was unable to drive one away from the vicinity of her trap, in which there were some birds, “and only after she secured a broom and actually struck at the intruder several tilnes, did it gWe up and abandon the premises.”
In its summer home in Li%bi-ador, the northern shrike seemed to be very tame, and we saw no signs of aggressiveness toward the few small birds that live there; probably it was living largely on insects. On August 18, 1912, I watched one for some time in Dr. Hettasch’s small garden and in the woods around it. It was flying in its direct slow flight from one tree to anotbev, or perching on a topmost twig, its body held erect, and flirting its tail up and down, or holding it straight out behind horizontally. Occasionally it darted out from its perch to chase some flying insect, or dropped down to the lower branches of a larch, where it seemed to be feeding on the ifuds and tender shoots, though probably it was finding insects there. lYhen making a longer flight to a more distant tree, it flew more swiftly in a slightly undulating course, alternating a few rapid wing strokes with downward glides in woodpeckerlike curves. If flying low, as it often did, as if to keep behind cover, it would suddenly swoop upward in an abrupt curve to reach its perch on a treetop. Occasionally, it would hover like a sparrow hawk over an open space, as if looking for mice or insects.
Francis H. Allen says in his notes: “A shrike I watched mousing over river meadows in Millis, Mass., January 25, 1931, hunted mainly by hovering. It would start off with two or three bounds in the air and then rise almost vertically for perhaps six to ten feet: that is practically vertically at the top of the rise: and then hover for some time, turning its head from left to right to scan the grassy marsh. It was a very pretty performance.”
Wendell Taber tells me of a rather unusual action that he saw: “As it sat on a twig the bird suddenly jumped to another twig slightly to one side and somewhat lower. I estimated the horizontal distance at about eight inches and the vertical descent at about six inches. The jump was accomplished entirely by leg and body motion, with the wings remaining folded throughout. The branch on which the bird landed was strong enough, so that no visible motion took place under the impact of the bird’s landing.”
I have never seen a northern shrike on the ground, nor can I find anything in the literature as to its method of progression there. It must jump or hop vigorously in pursuit of grasshoppers or crickets. Dr. Miller (1931) says that “loggerhead shrikes hop but do not walk. In moving sideways or backward one foot is moved independently of the other. While hopping, the body is held erect and the head held high unless the bird is engaged in investigating objects close to the ground.” Probably the northern shrike progresses in a similar manner.
Voice: I did not hear the northern shrike sing in Labrador. The singing season had evidently passed, as the young birds were fully grown and the molting season was at hand. The only notes I heard were a variety of twittering, chattering, squealing, or whistling notes, ~vith occasional gurgling warbles in soft tones. Other observers of Labrador birds do not mention its song.
The males, and sometimes the females, have often been heard singing at various times during their sojourn in the United States and much has been written about it. Aretas A. Saunders writes to me: “I first heard it many years ago in March, before I kept definite notes of singing. The only records I find of hearing the song in late years are November 8, 1921, March 25, and April 8, 1922. It is a longcontinued song, suggesting that of the mockingbird, but containing more harsh notes.”
Francis II. Allen describes it in his notes as a “song of indeterminate length, composed of caws and scraping notes and short, very pleasing liquid trills, with occasional whistling notes. The notes may be single and staccato, or given in series of three or four in the manner of a mockingbird. The whole is a formless, disjointed performance. When fleeing from an attacking crow, a shrike sounded a prolonged rattle of high-pitched ‘beady’ notes: like pip-pip-pip-pip, etc., uttered very rapidly.”
Eugene P. Bicknell (1884) writes:
I have heard a variety of notes from it in October, on Its first arrival, and in November; but its highest vocal achievement is in late winter and early spring. * An unusually vocal bird was observed on February 10, 1877: a morning when winter seemed quietly relaxing from long-continued severity. Perched in the sunlight, on the topmost spray of a tall oak, on an eminence commanding an expanse of changing landscape, It was alternately singing and preening its beautiful plumage. The song was a medley of varied and rather disconnected articulations, an occasional low warble always being quickly extinguished by harsh notes, even as the bird’s gentle demeanor would soon be interrupted by some deed of cruelty.
Frederic H. Kennard records in his notes the capture of a singing shrike on his grounds, and says: “I heard its warble, but having seen a robin before I saw the shrike, I thought it must he a young robin practicing, so like were the notes. I thought, however, that the young robin was mighty hoarse, so went to investigate. On dissection, this singing shrike proved to be a female.” A similar experience is thus recorded by Dr. Arthur Chadhourne (1890): “On the morning of April 8, 1890, when walking through the Fresh Fond Swamps at Cambridge, I heard a Butcher Bird (Lanius borealis) in full song. The bird was an usually fine singer, and quite a mimic, its medley of notes suggesting a combination of the Brown Thrasher and the Blue Jay, with an occasional ‘mewing’ sound much like the common Cat.bird. It was shot, and on sexing proved a female, the ovary being considerably enlarged.”
Several other observers have referred to the shrike’s power of mimicry. Mr. Forbush (1929) adds the song sparrow to those named above, and says: “One day Mr. Win. C. Wheeler, who can imitate many bird songs, whistled the song of a Robin as he approached a Northern Shrike. The bird immediately mocked his rendition of the song, and repeated it after him thrice.”
Field marks: Shrikes look superficially somewhat like chunky mockingbirds with thick heavy heads and bills, but there is a black band on the head, through and behind the eye; in the adult shrike the back is clearer, gull gray, browner in the young, and the breast is vermiculated with dusky; there is also much less white in the wings and tail; the latter is proportionately shorter than in the, mockingbird. Its posture and behavior are quite different. The loggerhead shrike is slightly smaller and is purer gray above and whiter below than the northern shrike.
Enemies: The worst enemy that the northern shrike ever encountered was the man with the gun on Boston Common, who killed over 50 of the birds in a single winter, many years ago, to protect the English sparrows soon after their importation. The tables are turned now, for one of the best things the shrike does is to help reduce the numbers of this ubiquitous foreigner, so the shrikes are now welcomed in the cities.
Harold S. Peters (1936) lists only one louse, Philopterwi subflave8cen.s, as an external parasite on the northern shrike.
Winter: The northern shrike comes southward to spend the winter in varying numbers at more or less regular intervals, depending probably on the variations in its food supply in its summer home. Sometimes it is abundant in New England in winter, sometimes rare, and sometimes entirely absent or very local. They were reported as very abundant in the winter of 1878: 79. Mr. Floyd (1928) called attention to a decided invasion in the winter of 1926: 27, in Maine, New Hampshire, Vermont, Massachusetts, Rhode Island, Connecticut, New York, and New Jersey, and they were unusually plentiful in Nova Scotia. He corresponded with bird-banders from New England to Virginia and learned that “during the six months from October to April, sixty-two Shrikes were reported destroyed by banders, while eight were banded and released.” He attempted to learn whether the abundance of shrikes coincided with the heavy invasions of redpolls, siskins, and other small northern birds, on which the shrike might prey, but the data accumulated did not confirm this theory; in fact, there was only one year out of eight in which the small birds and shrikes were both abundant.
David E. Davis (1937) has made a study of this subject and says in his interesting paper on it:
The Northern Shrike (Lanius borealis borealis) has attracted attention by its occurrence in New England and adjoining States in large numbers in certain years. Since the species is predatory, a correlation with the well-known cycle of mice (Mlcrotus spp., Dicrostony~r spp.) was suspected. * * * A thorough examination of the available literature was made for records concerning shrike invasions. It was soon apparent that the Christmas Bird Census in “Bird-Lore” supplied the only data which could be used to compare one year with another. These records are here presented in a graph showing the number of birds observed per census for each Christmas period. * * * That there is a definite cycle Is at once apparent from the graph. The average Is 4.2 years. It should be noted that there are two five-year periods and no three-year periods. The winters of maximum abundance are 1900: 01; 1905: 00; 1000-10; 1913: 14; 1917: 18; 1021: 22; 1920: 27; 1980: 81; 1034: 35. That there was a maximum in the winter of 1000: 01 is supported by Brewster (1906) who states that shrikes were not seen In 1902, 1903, or 1904, but were rather common in 1901. * * * It Is quite obvious that the mice increase and periodically die out. During the Increase of mice, the predators likewise increase. * * * When the mice disappear the predators first exhaust other prey and then either migrate or die.
Range: In the Eastern Ilemisphcre: to the limit of trees from Norway to western Siberia; in winter south to central France, northern Italy, western Rumania, and central Russia. In America, from Alaska and northern Canada to the central part of the United States.
Breeding range: The American races of the northern shrike breed north to the limit of trees in northern Alaska (Lower Noatak River, Kobuk Valley, and Seward Creek near Circle) ; central Yukon (Ogilvie Range) ; northern Mackenzie (Fort McPherson, Fort Anderson, McVicar Bay on Great Bear Lake, and Fort Reliance) ; northern Manitoba (Lac du Brochet and Churchill); and northern Quebec (Chimo). East to northern Quebec (Chimo and Indian House Lake) ; and Labrador (Lake Melville and the east coast). South to Labrador (Lake Melville) ; central Quebec (possibly Anticosti Island, Lake Abitibi); northern Ontario (Moose Factory and Fort Severn, probably; casually to Ottawa and Toronto) ; central Saskatchewan (Prince Albert and Carlton House; casually to Qu’Appelle) ; northern Alberta (Athabaska Delta) ; northern British Columbia (Thudade Lake and Atlin) ; southwestern Yukon (near Burwash Landing); and southern Alaska (Homer, mouth of the Chulitna River, and Nushagak). West to western Alaska (Nushagak, Kigluaik, and the Noatak River).
Winter range: The northern shrike probably winters occasionally nearly as far north as it breeds but winter records from much of that region are scarce. In the southern part of its winter range it is quite irregular, and it is likely that its southward wanderings are in search of food. Insofar as actual records go, this shrike winters north to central Alaska (Flat, Toklat River, and Chilkat) ; central British Columbia (Francois Lake and probably Thudade Lake); central Alberta (Belvedere, Edmonton, and Camrose) ; central and southern Saskatchewan (Cochin and Lake Johnstone) ; southern Manitoba (Aweme, Lake St. Martin, and Hillside Beach, Lake Winnipeg) central Quebec (Great Whale River, Quebec, and Bonaventure Island) ; and northern Newfoundland (Hare Bay). East to Newfoundland (Hare Bay, Salmonier, and Tompkins); Nova Scotia (Antigonish and Bridgetown) ; New Brunswick (Grand Manan) ; the New England States and Long Island (Orient) ; and occasionally central New Jersey (Morristown and Barnegat Bay). South to central New Jersey (Barnegat) ; southeastern Pennsylvania (Philadelphia, occasionally) ; Maryland (Baltimore) ; District of Columbia, rarely: North Carolina, rare or accidental (Pea Island) ; West Virginia (White Sulphur Springs, rarely; northern Ohio (Salem, Oberlin, and Toledo); occasionally southern Indiana (Bloomington and Vincennes) ; rarely southern Illinois (Mount Carmel) ; central Missouri (St. Louis, St. Charles, and Columbia) ; southern Kansas (Wichita and Coolidge); accidental at Fayetteville and Van Buren, Ark., and at Decatur, Tex.; south-central Colorado (Pueblo, Colorado Springs, and Salida) ; northern Utah (Ogden) ; central western Nevada (Reese River, Lahontan Valley, and Carson); and northern California (Rolands Marsh and Marysville); also occurs rarely or accidentally south to north central New Mexico (Las Vegas and Santa Fe) ; central Arizona (Flagstaff and Prescott), southwestern Utah (St. George), and central California (Sacramento). West to central California (Marysville) ; western Oregon (Grants Pass, Corvallis, and Blame) ; western Washington (Seattle, Sequin, and Bellingham) ; western British Columbia (Crescent, Courtney, and Francois Lake) ; and Alaska (Chilkat, Bethel, Akiak, and Flat).
The above ranges for the species in North America are divided into two geographic races. ‘The northern shrike (L. b. borealis) breeds east of Hudson Bay; the northwestern shrike (L. b. invictus) breeds from Alaska to Manitoba.
Migration: From the available records the northern shrike appears to be quite irregular in its migratory movements. Dates of spring departure are: Pennsylvania: Harrisburg, March 10. New York: New York, April 17. Massachusetts: Harvard, April 4. Maine: Wells, April 26. Ontario: Ottawa, April 18. Ohio: Oberlin, April 3. Michigan: Grand Rapids, March 29. lowa: Grinnell, March 31. Wisconsin: New London, March 23. Kansas: Manhattan, March 29. Nebraska: Neligh, March 31. South Dakota: Vermillion, March 28. North Dakota: Charlson, March 12. Manitoba: Margaret, April 6. Saskatchewan: Indian Head, April 21. Colorado: Yuma, April 4. Wyoming: Laramie, April 15. Montana: Bozeman, April 3. Washington: Pullman, April 8. British Columbia: Okanagan Landing, April 20.
Early dates of spring arrival are: Mackenzie: Fort Liard, April 2. British Columbia: Atlin, April 18. Alaska: Fairbanks, March 31.
Late dates of fall departure are: Alaska: Bethel, November 7. Yukon: Forty Mile, October 12. Mackenzie: Simpson, October 12. British Columbia: Atlin, October 12.
Early dates of fall arrival are: British Columbia: Chilliwack, September 27. Washington: Tacoma, October 11. Montana: Fortine, September 27. Wyoming: Yellowstone National Park, October 15. Colorado-Colorado Springs, October 2. Saskatchewan: Eastend, October 2. Manitoba: Awerne, October 3. North Dakota: Argusville, October 16. South Dakota: Pierre, October 21. Nebraska: Lincoln, October 27. Kansas: Onaga, October 19. Minnesota: Lanesboro, October 18. Wisconsin: La Crosse, October 18. Iowa: Keokuk, October 19. Michigan: Sault Ste. Marie, October 9. Illinois: Glen Ellyn, October 24. Ontario: Toronto, October 15. Ohio: Youngstown, October 16. Pennsylvania-: Erie, September 21. Maine: Phillips, October 19. New Brunswick: Scotch Lake, October 17. Massachusetts: Danvers, October 31. New York: Orient, October 22. District of Columbia: Washington, November 7.
From the few banded northcrn shrikes the two rccoveries available are of some interest. One banded at Hepburn, Saskatchewan, on July 4, 1931, was found dead on September 23, 1931, at Cross Timbers, Mo.; and another banded at Harwich, Mass., on November 8, 1934, was found dead about April 1, 1936, at Clarenceville, Quebec.
Casual records: Eight specimens have beeii collected in Bermuda: October 31, 1846; January 23, 1847; March 12. 1850; January 1872; January 1, 1876; and three without dates.
Egg dates: Alaska: 2 records, May 21 and June 27.
Labrador: 3 records. June 3 to 17.
Mackenzie: 3 records, May 20 to June 11.
LANIUS BOREALIS INVICTUS Grinnell
This western race of the northern shrike was described by Dr. Joseph Grinnell (1900), who says of it:
L. borealis invictas differs from L. borealis borealis in larger size, paler coloration dorsally and greater extent of white markings. These differences are fairly comparable to those between the southwestern L. tadovicianua crcubUoridcs and L. ludovicianus proper. * * * During the fall the Northwestern Shrike was met with In the Kowak Valley rather sparingly. Single individuals would he seen, one or two in a day’s tramp, in the willow bottoms where they werc the terror of the redpolls. On only one occasion did I see more thin one in a place. * * * None were seen after October 26th, until March 22nd, when one was secured. During April and May they became fairly common, that is, for shrikes.
Harry S. Swarth (1920) was evidently iiot greatly inipressed with the wisdom of recognizing this race. He found that there are Alaskan birds “that lie well within the range of variation of eastern birds, and there are one or two eastern birds with white markings on the tail feathers nearly as extensive as in any western ones.” After examining a series of over 80 specimens, about equally divided between eastern and western birds, he writes: “There are a number of winter birds in this series from points lying l)etween the Great Lakes and the Rocky Mountains, and nearly all of these I am unable to allocate t.o an eastern or a western race with any degi’ee of assurance. Thus, while recognizing in the northern shrike a tendency toward development of the characters ascribed to invictus in the western part of its habitat, it seems to me so impossible to define the boundary between an eastern and a western race, or to identify nwst winter birtls taken south of the breeding range, that 1 am disinclined to use different names for the variations exhibited.”
Dr. Alden H. Miller (1931) does not agree with the above, saying: “I cannot agree with Swarth (1926, pp. 135, 13G) that it is impossible to define the boundary behveen the eastern and western races of this species, difficult as it is to identify some winter specimens. The boundary line between the breeding ranges is poorly known, I believe, only as a result of the extremely meagre collections of breeding birds from critical localities.”
His distributional map shows an area of intergradation from the west coast of Hudson Bay westward for breeding birds, and directly southward from that area into the United States for wintering birds. It is interesting to note that this is just where one would expect to find the intergrades that Mr. Swarth had difficulty in identifying I He says that “an immature specimen from Fort Churchill, Manitoba, taken in July may be considered intermediate between the two races although its dimensions are those of invictu&” This seems to demonstrate, as satisfactorily as our present knowledge will allow, that invictua is the breeding form from this point westward.
Nesting: N either Dr. Grinnell nor Mr. Swarth found a nest of this shrike, but Roderick MacFarlane (1908) took a fine nest of the northwestern shrike at Fort Anderson, northern Mackenzie, on June 11, 1863; it was in a spruce tree, 7 feet from the ground; he describes it quite fully, as follows:
It is in many respects In striking contrast with the nests of its kindred species of the Southern States of the Union, far exceeding them in its relative sIze, in elaborate finish, and warmth. It is altogether a remarkable example of what Is known as felted nests, whose various materials are most elaborately matted together into a homogeneous and symmetrical whole. It is seven inches in diameter and three and one half in height. The cavity is proportionately large and deep, having a diameter of four and one-half inches and a depth of two. Except the base, which is composed of a few twigs and stalks of coarse plants, the nest is made entirely of soft and warm materials most elaborately interworked together. These materials are feathers from various birds, fine down of the eider and other ducks, fine mosses and lichens, slender stems, grasses, etc., and are skilfully and artistically wrought into a beautiful and symmetrical nest, strengthened by the interposition of a few slender twigs and stems without affecting the general feltlike character of the whole.
Several nests have been reported, from the more southern portions of Canada, as placed in deciduous trees, but these were probably extra large nests of white-rumped or migrant shrikes.
There is a beautiful nest of this shrike, taken by Johan Koren in Alaska on May 21, 1913, in the Thayer collection in Cambridge. It is a bulky nest, nearly 9 inches in external diameter and about 4 inches in height; the inner cup is over 4 inches in diameter and 2V2 inches deep. It is made of coarse grasses and weed stalks, inner bark, and plant down, reinforced with fine and coarse twigs, and thoroughly mixed throughout with white ptarmigan feathers, with which it is also profusely lined, forming a soft, warm bed. It was placed 12 feet from the ground in a cottonwood tree and contained the unusual number of nine handsome eggs.
W. E. Clyde Todd has sent me the following note from Arthur C. Twomey: “A nest of this shrike was found on June 20, 1942, on the outer fringe of the transitional willow community that divides the coniferous forest from the true tundra. It was located six miles west of the southwest tip of Richards Island, Mackenzie River Delta, N. W. T., Canada. The nest was in a dense growth of willows about twelve feet from the ground. It was a large, bulky structure made up of dead willow twigs, dry sedges, grasses, and strips of willow bark. It had a deep inner cavity that was completely lined with a half inch layer of winter ptarmigan feathers. The five half-incubated eggs were well insulated against the rapidly changing temperatures.”
Eggs: The nest described above by MacFarlane (1908) contained six eggs, and he reports another nest that contained eight. The eggs are evidently indistinguishable from those of the northern shrike. He describes them as “of a light greenish ground, marbled and streaked with blotches of obscure purple, clay colour and rufous brown.” The measurements of 14 eggs average 27.3 by 20.4 millimeters; the eggs showing the four extremes measure 28.1 by 20.0, 27.3 by 21.0,26.3 by 20.7, and 26.5 by 20.0 millimeters.
Young: In the Atlin region of northern British Columbia, Mr. Swarth (1926) collected a brood of six young, “just able to fly,” on June 30. “The young birds, huddled together in a spruce thicket, were being fed by one parent, which escaped. * * * The young birds were extremely noisy; it was the incessant squalling for food that drew our attention, from a distance. Their stomachs were well filled, mostly with insect remains, including some small Coleoptera; in one stomach there were parts of a very young ptarmigan chick, including the bill.”
Plumages: Mr. Swarth (1926) writes: “A notable feature of the shrikes in juvenal plumage is their gray coloration. In the freshly acquired first winter plumage there is a decidedly brown tone both above and below, but, save for the wing markings, none of this appears in the juvenal stage. This plumage is mostly clear gray, slightly darker on the dorsum, and finely vermiculated below.”
An adult male, collected on July 28, “is in the midst of the annual molt. Above and below the old feathers are extremely pale colored. The underparts are almost pure white, the old feathers having lost every vestige of the dusky vermiculations. Such markings show plainly enough on the new breast feathers, just coming in.”
Food: Dr. Grinnell (1900) saw a northwestern shrike “carrying prey to a clump of spruces further up the channel where there must have been a brood of young. On one occasion the bird was carrying a redpoll, but usually it was a lemming or meadow mouse. Once he had grasped in his claws a lemming so heavy that it dragged in the water as the bird flew laboriously across the river.” The stomach of an adult collected by Mr. Swarth (1926) held insect remains.
Behavior: Ernest T. Seton (1911) writes:
One afternoon I heard a peculiar note, at first like the ‘cheep y-teet-tcet” of the Pine Grosbeak, only louder and more broken, changing to the jingling of Blackbirds in spring, mixed with some Bluejay “jay-jays,” and a Robin-like whistle; then I saw that it came from a Northern Shrike on the bushes just ahead of us. It flew off much after the manner of the Summer Shrike, with flight not truly undulatory nor yet straight, but flapping half a dozen times: then a pause and repeat. He would dive down near the ground, then up with a fine display of wings and tail to the next perch selected, there to repeat with fresh variations and shrieks, the same strange song, and often indeed sang it on the wing, until at last he crossed the river.
S. F. Rathbun (1934) says: “On one occasion we paced this shrike in flight. For more than a mile the bird flew alongside the road or over it and in front of us as we drove, at no time distant more than one hundred feet. Time shrike was flying at the rate of thirty-two miles when we first contacted it, but as we kept up with it the bird imperceptibly increased its speed to forty-two miles, and once for an instant reached forty-five miles.
“This test was very fair. There was no wind blowing, and the shrike maintained an almost direct flight either in front of, or nearly at the side of the automobile.”