Though Brewer’s Blackbirds were formerly only found in the central and western U.S., dramatic habitat changes due to forest clearing and agricultural changes in the early 1900s enabled their rapid expansion to the east. There are both migratory and non-migratory populations of Brewer’s Blackbirds in different regions of the country.
Studies have found that Brewer’s Blackbirds spend significantly more time foraging when the winter temperature is colder. This, together with the short winter days, means that they cannot winter as far north as other species that are better adapted to the cold.
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Description of the Brewer’s Blackbird
The Brewer’s Blackbird is sexually dimorphic, though both sexes have a typical blackbird shape, and a thick, pointed bill.
Males are all black with a purplish sheen to the head and greenish sheen to the wings and upperparts. They have pale eyes. Length: 9 in. Wingspan: 15 in.
Females are dull brownish above and below and usually have dark eyes.
Seasonal change in appearance
Fall adult males lack the glossy sheen and resemble females, but are darker and more heavily marked.
Juveniles resemble winter adults.
Brewer’s Blackbirds inhabit prairies, fields, and areas near human habitation.
Brewer’s Blackbirds eat insects and seeds.
Brewer’s Blackbirds forage on the ground or in shallow water.
Brewer’s Blackbirds are resident throughout a large portion of the western U.S., and breed over large areas to the north of their permanent resident range. These migrant birds winter both east and south of their permanent range. The population has declined in recent years.
Bent Life History
Visit the Bent Life History for extensive additional information on the Brewer’s Blackbird.
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
Brewer’s Blackbirds to some extent fill the niche of the Common Grackle in the western U.S.
Like most blackbirds, Brewer’s Blackbirds often associate with other blackbird species outside of the breeding season.
The song consists of a high, raspy, or buzzy sound. A “chek” call is given as well.
Common Grackles have longer tails.
The Bronzed Cowbird has a red eye.
Rusty Blackbirds have thinner bills, and all plumages other than the adult male’s show rusty tones.
The Brewer’s Blackbird’s nest is a cup of twigs, grass, and weeds and is lined with finer materials. It is placed in a tree or on the ground.
Number: Usually 4-6.
Color: Grayish in color with darker markings.
Incubation and fledging:
The young hatch at about 12-14 days, and fledge at about 13-14 days, though remaining dependent on the adults for some time.
Bent Life History of the Brewer’s Blackbird
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 Brewer’s Blackbird – the common name and sub-species reflect the nomenclature in use at the time the description was written.
EUPHAGUS CYANOCEPHALUS (Wagler)
At least two proposals have been made to divide this species, using the names E. c. minusculus and K c. aliastus, but neither of these subspecies has been accepted by the A. 0. U. committee on nomenclature.
As Brewer’s blackbird is found in large, conspicuous flocks in open places, often close to human habitations, it is a familiar bird throughout a considerable part of western North America. Although it occurs throughout the year in areas such as farming districts and even in villages and towns, this species also resorts to higher elevations where it nests remote from man .
The Brewer’s blackbird has profited by human alteration of the environment. A large part of its time is spent perching on electric wires, where it rests, preens, calls, displays, and uses the wire as a guard perch during breeding activities. This bird forages extensively on lands that have been converted from brush or forest to pasturage, and on freshly plowed soil; it eats some grain (usually waste); and frequents golf courses, lawns, and irrigated areas. Such advantageous conditions possibly contribute to the increase of this species. Dawson and Bowles (1909) say that in Washington it has profited by human settlement of the land and by the spread of cattle; and Kennedy (1914) says that in the Yakima Valley the bird has “prospered greatly” due to irrigation. Grinneil and Miller (1944) state that, in some areas in California, it “apparently has increased as a result of human occupation of the land.” The Brewer’s blackbird seems to have been extending its range eastward in recent years, and it has now been recorded as a breeding species in Ontario, eastern Minnesota, Wisconsin, and Illinois. What seems to be the first published record for Ontario, of both occurrence and breeding, was made by Allin and Dear (1947); on June 14, 1945, a male was collected and a nest with young found in a cleared area near Port Arthur. The male was taken in a colony of eight birds, including a brown-eyed female, that occupied 8 acres. Concerning the bird’s eastward extension in Minnesota, Roberts (1932) says that it is “one of several birds that have extended their ranges eastward across the state in comparatively recent years.” It has been abundant in the Red River Valley “since the earliest records for that region; the first nesting colonies in the eastern part of the state were discovered at Minneapolis in 1914.* * *
Previous to that time it was either not present or so rare as to have escaped observation. Now it is a common summer resident, breeding in colonies throughout the state; absent or rare as a nesting bird in most of the southern counties.”
“The presence of the Brewer’s Blackbird in Wisconsin prior to the years 1926 and 1927 was rare,” writes Schorger (1934), who remarks that “the recent extension of its range is quite remarkable.” The year 1926 marked the beginning of the influx, and Schorger says that “it is now possible to state that Brewer’s Blackbird is at present a common summer resident, breeding in a narrow area extending from Polk County in the northwest, to Walworth County in the southeast.”
I (1952) carried on a behavior study of this species principally at a breeding colony, “the river-mouth colony,” at the mouth of the Carmel River, Monterey County, on the central coast of California, for six breeding seasons from 1942 through 1947, with check observations in 1948. The colony is situated at the edge of a marsh. The birds nest in Monterey pines (Pinus radiata) which, although native to the region, are planted along the streets of a subdivision adjacent to the marsh, on what was originally chaparral land. Although the birds forage on lawns, streets, and food-trays, they spend a large part of their time on the marsh area, undisturbed during the years of this study. Tules (Scirpus), which grow in patches on the edge of the marsh, as well as the pines, are used for roosting and daytime resting places. Electric light wires and poles along the streets are used for perching by the flock as well as for display and guard perches by individual birds.
In the study, 318 Brewer’s blackbirds, 158 males and 160 females, were color banded. Over the period of study, 117 marked birds bred in the colony; in addition to these there were 8 birds of each sex entering into the breeding activities of the colony that I was unable to band. Many of the remaining 201 banded birds were found at other colonies in the region at various seasons, and some of them were found breeding at those places. The banding station was maintained throughout the year near a house in the center of the colony.
The breeding period, which extends roughly from the end of January into July, may be divided into the following phases of activity: 1. segregation and assortment into pairs: pair formation; 2. nestbuilding, copulation, and egg-laying; 3. incubation; 4. nestling care; 5. fledgling care.
Spring and courtship: In phase 1 old pairs (that is, pairs returning from the previous year) reassociate and new pairs are formed. By “new” is meant some combination involving either young birds in their first year, birds banded during the season (ages could not be determined after the fall molt), or, rarely, a recombination of individuals that had previously bred in the colony.
My study at the river-mouth colony revealed that there is no period of male isolation as in a typical territorial species. The flocking behavior of fall and winter gradually gives way as the birds associate more and more in pairs. The activities of the pair are not confined to any territory (except that later on there is a focus of attention at the nest site) and the birds may at first carry on pairing activities while grouped together in a flock .
A number of displays and accompanying calls are used throughout the breeding season.
The RUFF-OUT is employed by both sexes, but more frequently by males. The bird holds the bill nearly horizontal, or pointed somewhat upward and ruils out many of the contour feathers, especially those of the head and neck, the breast, and upper tail coverts (the rump feathers remain flat); at the same time it partially spreads the wings downward and fans and depresses the tail. As the ruffing and spreading reaches a climax either a squcee or scld-r-r-r-up is uttered and the display immediately subsides. The notes are never uttered without the accompanying display, though the latter varies greatly in the extent of ruffing and spreading. When used by the female it is less developed and the utterance is more subdued. The whole display lasts only a second or two. It functions as a threat, but is also used in mutual display between pairs, as described below. As a threat it is much more frequently used by the male.
The MALE PRE-COITIONAL DISPLAY, employed by the male immediately preceding his mounting the female, is a more exaggerated form of HUFF-OUT, but the bill is pointed downward and the display held longer. If it is performed on the ground the wings and tail may actually scrape the earth as the male approaches the female. Sometimes, in this display, the male struts in a half-circle in front of the female before mounting.
In the FEMALE GENERALIZED DISPLAY, the bill is held upward at a slight angle; no feathers are ruffed out; the wings are held somewhat out from the body, drooped, and vibrated; the tail is cocked but not spread. This display is always accompanied by a series of kit notes. The display has a definite attracting effect on the male and also is part of the female’s response to his advances .
The FEMALE PRE-COITIONAL DISPLAY, or “copulatory invitation,” should probably be considered a more fully developed female generalized display, which it resembles, except that the body is tilted forward and the tail cocked at a steeper angle. It is accompanied by a specific series of soft, low, tapping notes. Before the male mounts the wing quivering ceases and the female’s body becomes rigid.
The MALE ELEVATED TAIL DISPLAY is similar to the female generalized display in body appearance, wing action, and tail cocking, but with the tail somewhat spread and the wings possibly held out a bit wider. This is accompanied by the series utterances chug-chugchug (see p. 325). It is possible that this display may function as an invitation to the female or an indication of the male’s receptive state. It is never addressed to another male and has no significance as a threat.
The HEAD-UP DISPLAY is used regularly by males, rarely by females. With the bill pointing nearly vertical the body is drawn upward without ruffing the feathers. In its fullest development the bird has a slim, drawn-out appearance. This display is held for an appreciable length of time, unlike the momentary ruff-out, and there is no accompanying call. It functions as a threat.
All these displays except the pre-coitional ones have been observed in more or less rudimentary form in the flock during the non-breeding season. The threat displays (ruff-out and head-up) are used in disputes over food and in other aggressive situations at all times of year.
Activities that I have termed “pairing behavior” are as follows:
Pairs WALKING TOGETHER segregate from the flock and forage together, usually keeping within a few feet of each other .
Pairs, either isolated or in the flock, perch on wires or on the tips of pine boughs; if on the wires the distance between male and female is quite regularly about 18 inches. There they indulge in MUTUAL DISPLAY, exchanging the ruff-out, with squeee and.schl-r-r-r-up notes. They may keep this up for several minutes. It usually ends by their flying off together, the female usually taking flight first and the male immediately following; sometimes the takeoff is nearly simultaneous.
When perched on the wires the male may hop at, or dart toward, the female. This action, THE DART, 15 often preceded by the female assuming the generalized display, or it may cause her to assume it; or the female may respond with the rnff-out.
Frequently, in response to THE DART, the female may fly off, the male in close pursuit, in a more or less circular flight. In this action, THE CHASE, a third bird or even a second pair, often joins.
At the river-mouth colony, Phase 1 usually begins toward the end of January or in February, when a change from winter behavior can be detected. Instead of spending a large part of the day in long foraging expeditions away from the colony area, the flock remains longer in the vicinity of the colony. Pairs sort themselves out; a pair may perch, isolated, on the wires or on the tips of pine limbs and engage in mutual display, then fly to the ground to forage together. Other pairs may be feeding there also. Although the flock may be all together, pairs can be detected within the group walking together and maintaining a fairly constant interval between the male and the female, which is less than the distance to the next pair. Suddenly they all flush and the pairs bunch together into a flock and fly off. Often the flock circles about and alights on the wires. If the members of a pair do not happen to light together individuals shift their positions on the wire until the flock is sorted pair by pair. Thereupon mutual display starts again.
Individual pairs vary as to the date when they commence to act as a pair. Also there is a gradual increase in the time that pairs spend in segregation and a corresponding decrease in the time spent in the flock. Although pairing behavior may start as early as the end of January, there are brief intervals in the day when the birds revert to flock formation even as late as April .
Constancy in pairing behavior with the same mates is also arrived at gradually. Members of old pairs are less frequently involved in pairing behavior with individuals other than the “proper” mate and thus they tend to be constant from the beginning. New pairs, however, perform pairing behavior with other birds in many instances until finally the “true” pair forms and remains constant through the remainder of Phase 1. This is not to say, however, that after pairs are formed, mated males do not respond to the displays of a neighbor’s female, as indeed they do. Females perform the generalized display more and more frequently as Phase 1 progresses, even though copulation is in the future. The intruding male responds to this display by approaching in the ruff-out or even pre-coitional display, or he may just walk or fly toward the female. But the female is constantly guarded by her mate, who drives off the intruder, either by flying directly at him, or walking deliberately head-up, between the female and the intruder. The latter responds with the head-up display and both, still holding this posture, walk stiffly abreast of each other away from the female. Sometimes both males shift to the ruff-out and remain facing each other, exchanging this display. When they do, this the action looks very like a pair in mutual display (there is no head-up in mutual display, however). Rarely, a fight occurs when both males flutter up together and peck and claw at each other.
After the pair is formed the members are almost always together, becoming separated only for brief intervals. The male guards his mate from the approaches of other males with increasing constancy.
In Phase 1 there is some toying with nesting material by both sexes and even carrying it to a site. The male of the pair is sometimes the first to hold nesting material in the bill, but he rarely places it at a nest site. Actual nest construction is accomplished almost entirely by the female, and not until Phase 2 commences. Bendire (1895) says that “both sexes assist” in nest construction, but at the rivermouth colony the male’s activity with nesting material is almost entirely functionless as far as the actual construction is concerned.
In Phase 1 there is considerable aggressive behavior and even fighting for the possession of nest sites, even though actual nest construction is still to come. This fighting is largely between females. A fight between females at a nest site usually brings a response from their mates, who alight nearby but do not always act belligerently at first. The approach of the males may cause one or both females to assume the generalized display, and the males then tend to guard their mates.
Pairs acting as a team will defend a nest site, but in such cases it is more often the female rather than the male who initiates the attack. Males will, however, defend the nest site without the female being present.
Although Phase 1 may start as early as the third week of January, actual nest construction, copulation, and egg-laying for the first brood (Phase 2) does not commence earlier than April, usually not until the second or third week (the earliest observed copulation: April 6, 1945). Thus Phase 1 of the first cycle may be stretched out for as long as 12 weeks. Phase 1 of subsequent cycles is exceedingly brief and can possibly be considered absent .
Males were both monogamous and polygynous; an individual might be polygynous one year and monogamous the next. The number of breeding males in the colony varied from 13 to 31; females from 14 to 36. Polygyny varied from one polygynous male in 1943, when the population was 13 males to 14 females, to 12 polygynous males in 1947 when the population was 18 males to 36 females. The number of mates per polygynous male was generally two; but in 1946 six males has two females each and one had three. In 1947 seven males had two, four had three, and one had four females.
When polygyny occurs it usually comes about in the following fashion: When the female is incubating (Phase 3) the male does not guard her constantly as he did formerly; and he takes no part in incubation. Consequently he pays more attention to other females. If an unmated female, or, more rarely, a female whose mate does not seem to be aggressive enough to guard her, is present, the unoccupied male may take this female polygynously as a “secondary” female. More than one secondary female may be acquired successively in this fashion.
In most cases the male guards the secondary female as assiduously as he had his primary female, and I did not become aware of the new attachment until the secondary female had already started nest construction and copulation was being performed. As in second cycles, Phase 1 may be extremely short, a matter of only a few days, or may be passed over entirely.
At about the same time that the secondary female starts to incubate, the primary’s eggs have usually hatched and the male assists in feeding the nestlings. The periods that the young are in the two nests of a polygynous male may overlap and the male generally feeds at both nests. – This attention by the male to nestlings at two nests has been observed on the same day. Where simultaneous observation of both nests was possible, the male was sometimes seen to make feeding trips to each nest, dividing his time irregularly between the two. Likewise, attention to nestlings in one nest and fledglings from the other has occurred on the same day .
In the exceptional year, 1947, when the ratio of males to females was one to two, polygyny was at its height. There were certain cases of polygyny in which it was difficult to determine whether the usual attention was paid to the secondary female. There were also certain cases in which a polygynous male acquired mates almost simultaneously, and the timing of the cycles of these females were more or less parallel.
Males were observed in 1947 feeding nestlings at more than the usual two nests; one fed at the nests of his three females; another brought food to the nests of his four mates. However, since never more than two nestling periods of any one polygynous male were known to overlap, two was the maximum number of nestling broods fed on the same day.
Concurrently with this state of polygyny there was a remarkable faithfulness in the remating of primary pairs. Of the 45 cases in which both members of a primary pair were present the following year, 42 remated and only 3 were “divorced.” In addition, among the returns there were six birds that had been mated to unbanded birds the previous year. Some of these unbanded birds may, of course, have returned the following year and might have added to the total of either faithful pairs or divorces. In some cases primary pairs remated for a number of consecutive seasons. Of the total of 70 primary pairs, 44 were maintained for 1 year, 15 for 2 years, 7 for 3 years, 3 for 4 years, and 1 for 5 years. No male had the same female in secondary status more than once.
A monogamous male’s mate and the first seasonal mate of a polygynous male are considered primary females; the mate, or mates, of a polygynous male which are subsequently acquired in the same season are considered secondary females. (In a few cases in the exceptional year 1947, designations as to primary and secondary status were made with possibly some arbitrariness.) Thirty-four banded females were always primary throughout their years of occurrence; 20 banded females were secondary and 15 changed their status. Less than half the females in the 1-year group of survival were primary but only three banded secondaries survived for two or more years, whereas the primary, and those of changing status, showed survival periods extending into the fifth and sixth year. Because 15 females changed their status over the years of their survival, it is believed that had the 20 banded females which were in the “always secondary” group survived longer (only two survived for 2 years and one for 3) they, too, might have changed and become primaries for part of their years as breeders in the colony .
Nesting: Writing of the Brewer’s blackbird in California, Grinnell and Miller (1944) say that its habitat “in the spring season [is] grassland, meadows, or moist lake and stream margins, with trees or tall bushes in the vicinity which may be used for lookouts, roosting and nesting.”
C. W. Lockerbie (MS.) says of the bird in Utah: “The large open mountain valleys along the eastern slope of the Wasatch mountains are favorite summer habitats for these birds, e. g., Parley’s Park, Summit County, 1 to 4 miles wide and 10 miles long and about 6,500 feet elevation, with willow clumps along all water courses, a few tall cottonwood trees, and much of the land in wild hay. Dairying and stock raising are the only pursuits. No less than 50 pairs of blackbirds breed in this area; 200 birds, more or less, after July 15 are about the usual number observed. My earliest observations has been, May 25 and my latest September 7, though their residence period doubtless extends beyond these dates.”
In Colorado “they range from 4,000 to 10,000 feet in altitude and seem to prefer the open meadow along streams and adjacent to evergreen forests,” says R. J. Niedrach (MS.) .
In Nevada the species “uses a wide variety of situations for nesting sites,” writes Linsdale (1936a). This statement may well be applied to its nesting adaptability over its whole range. The nests may be placed on the ground or up to 150 feet above the ground; in the sedges of a marsh; in bushes of wet or dry areas; in many kinds of living trees and in the broken tops of stubs; in windbreak hedges at ranches; in ornamental trees and shrubs in parks and gardens or along the streets of towns; near plowed fields in agricultural areas; in semiarid situations; or along streams in mountain meadows at high altitudes.
Bendire (1895) writes that at Camp Harney in southeastern Oregon the nests were frequently placed on the ground “or rather in the ground, the rim of the nest being flush with the surface.” Quite a number were found in this situation, even when suitable trees and bushes were available. These ground nests were located on the edges of perpendicular banks. Ground nesting has also been reported for California by Grinnell, Dixon, and Linsdale (1930), who also report nesting in “a clump of sedge” and in “drowned brush-clumps out in the water.” Linsdale (1938) reports ground nesting in Nevada; Cameron (1907) in Montana, and Schorger (1934) in Wisconsin.
Among the writers who mentioned nest situations in willows fringing a swamp or stream, in cottonwoods, and in various bushes on river and creek banks are Dawson and Bowles (1909) for Washington and Cameron (1907) for Montana.
Nesting in the broken tops of dead trees in the Lassen Peak region of California is reported by Grinnell, Dixon, and Linsdale (1930). Dawson and Bowles (1909) describe nests “in cavities near the tops of some giant fir stubs none of them less than 150 feet from the ground.” But the “most favored nest sites” in California, according to Grinnell and Miller (1944), “are in dense masses of foliage, especially of conifers.”
La Rivers (1944) found a large variety of trees and shrubs used for nesting in Nevada; sagebrush (Artemisia), the most prevalent shrub, was most often used.
Although usually nesting in groups, the Brewer’s blackbird does not nest in such dense colonies as some other icterids, notably the tricolored redwing (Agelajus tricolor). This may be due to wider tolerance in habitat requirements, causing less concentration. Some observers report the nesting pairs as “somewhat scattered” and other pairs nesting “singly.” Bailey (1902) writes that “it nests in much smaller colonies than many of the blackbirds, five to ten pairs being the common number.”
In California R. M. Bond (MS.) found a colony “in a row of small Eucalyptus ficifolia near Carpenteria, three adjacent trees contained 21 nests (spring of 1935) with none in the remaining half mile or so of row. There were five or six nests in a yard tree (Acacia mekrnorylon) about 30 feet from the nests in the eucalyptus * * “‘. ‘The next nearest nesting colony was about a mile away in a windbreak of Monterey cypress.”
Linsdale (1938) writing of the Toyabe region of central Nevada says that Brewer’s blackbirds were found “in small colonies” and that the colonies varied in size from 3 or 4 to about 20 pairs. Within each colony “pairs tended to select similar nest sites.” Ridgway (1877) found a large colony in a group of pitiion pines at the south end of Pyramid Lake, Nev., on June 3, 1867. There were more than 100 nests, nearly every tree containing at least one. Several trees had two or three nests. Each nest was on a horizontal limb, usually near the top of the tree, well concealed in a tuft of foliage, and the majority of nests contained young.
La Rivers (1944) found that on a 15-acre tract 14 miles northwest of Reno, Nev., during the period May 17 to June 16, 1934, there were 107 nests of this species, a density of “slightly more than 7 nests per acre.” This indicated, he adds, a “heavy infestation for the region.~~ In the area within about a 12-mile diameter around the river-mouth colony I found nine other colonies and no pairs nesting singly, although it is possible that a single pair might have been overlooked. Some nests on the peripheries of the colonies were considerably more isolated than the majority of nests toward the centers. The rivermouth colony was a quarter mile west of the nearest other colony, the second nearest being a mile to the north.
Monterey pines were used for nesting, at some of the nearby colonies, and also live oaks, Monterey cypress, and Baccharis. One colony was at a golf course, another at a dairy farm, and another in trees in the business district of Carmel. All these colonies were adjacent to favored foraging areas.
In no year did the river-mouth colony exceed an area covering 9 acres. Every year the greatest density of nests was confined to the center area of 1 acre. Considering only the first nesting for the season of each female in the years 1944: 46, the density for the whole colony varied from 4.1 nests per acre in 1944 to 6.7 in 1946, whereas in the center acre alone the density varied from 14 in 1944 to 23 in 1945. Three or four pines in the center acre were particularly attractive to the birds. One pair of these trees, with trunks 4 feet apart and branches intermingling, but separated from the other trees, had a height of 45 feet and a combined spread of about 48 feet. This pair of trees contained 7 nests in simultaneous use in 1945. The nests varied from 21 to 42 feet above the ground; no two nests were closer together than about 9 feet nor farther apart than about 37. This represents the maximum crowding in the colony. Possibly such crowding was partly due to the fact that the trees were not evenly distributed over the 9 acres.
The arrangement of nests of polygynous males does not suggest a territory embracing them all, as is the case in some polygynous species, such as the yellow-headed blackbird (Xanthocephalus xanf hoeephalus). Although the nests of a polygynous male may be in the same tree, one of the nests may be as near or even nearer to the nest of another male than to its own second nest. But frequently the nests of a polygynous male were in different trees, often considerably farther separated than the nests of different males, with one or more other nests in between. The distance between two nests of one male has been as much as 282 feet.
The height of nests above the ground at the river-mouth colony varied from 7% to 42% feet. Thirty-five nests in 1945 averaged 27.2 feet and 37 in 1947 averaged 22.4 feet above the ground. (Many of the nesting trees, being in gardens or along the streets, had their lower branches trimmed.) Nests were ordinarily placed near the ends of branches in thick tufts of needles, and often partly supported by bunches of cones. The birds occasionally used planted Monterey cypress also .
The nest was described by Dawson (1923) as “a sturdy, tidy structure of interlaced twigs and grasses, strengthened by a matrix of mud or dried cowdung, and carefully lined with coiled rootlets or horsehair.” Some writers report mud used in the nest and others make no mention of it. A “mud cup” is mentioned by I. McT. Cowan (MS.) at Vancouver, British Columbia. Schorger (1934), in his description of a nest in Wisconsin, does not mention mud. Goss (1891) says that the nests he found on the ground at Chama, N. Mex. “were all without a trace of mud.”
At my colony grasses, pine needles, etc., were seen in the bills of nest-building females; many females frequently gathered horse manure and mud, a combination that, when dry, makes a firm, plasterlike cup.
The dimensions are given by Macoun (Macoun and Macoun, 1909): “In size it averages over 6 inches across, with a cup over 3 inches and a depth of at least 1~ inches.”
In Phase 2 (nest-building, copulation, and egg-laying) the male, although he takes no part in the actual construction of the nest, usually accompanies the female on each trip as she gathers material and carries it to the nest. At this time they make a long, continuous series of trips in contrast to the toying with and dropping of nest materials, or occasional trips to a nest-site, of Phase 1. When the female enters the tuft to place the material and mold the nest, the male perches nearby and displays the ruff-out, uttering acid -r-r-r-up and squeee. He uses one of several habitual guard perches, a wire, a pole or a branch tip. From this perch he may drive other males if they come near the nest site or into the tree. In this respect there is a certain amount of localized aggression by the male. But such localization does not take place until after the pairs have been formed in Phase 1. The greatest portion of the male’s aggressive activity is directly concerned with guarding his female against the approaches of other males. This guarding, or aggression concerned with a sexual situation which reaches its height in Phase 2, is not localized; i. a., it has little, or only incidental, connection with any particular area or territory and may occur at any point on the wires, along the streets, on the edge of the creek, or several hundred yards out on the adjacent marsh.
In Phase 2 the female exhibits the pre-coitional display frequently, and other males as well as her mate respond; among the males, rushes and threat displays are frequent. These advances by intruding males and the guarding actions by the mate, which begin in Phase 1, reach their height of occurrence in Phase 2, which, from the beginning of actual nest construction to the completion of the clutch, lasts about 10 days or 2 weeks, at the most.
Eggs: The number of eggs in a clutch varies from 3 to 7; Bendire (1895) and Hoffmann (1927) are the only writers I know who have given a number as high as 8. Cowan (MS.) says that in British Columbia “5 eggs is the most frequent number.” Dawson and Bowles (1909), referring to the species in Washington, and Dawson (1923), referring to California, give the number per set as “4: 7, usually 5 or 6.” La Rivers (1944) in a month of field study near Reno, Nov., found 107 nests containing a total of 521 eggs. The clutches were divided as follows: 23 with 3, 21 with 4, 22 with 5, 29 with 6, and 12 with 7 eggs each.
Ray (1909) found numerous nests of this species in the region about Lake Tahoe, Calif., in May and June 1909, nearly all of which were in small “tamarack pines, often mere saplings, from four to fifteen feet up, and but poorly concealed” (a notable exception was one nest placed on a wharf piling which was standing in water 3 feet deep). He says that “five was the usual complement of eggs, tho often four or six, and sometimes only three.” The eggs he examined “showed great variation in size, shape and coloring.”
Dawson (1923) also notes variation in pattern and coloration. He writes that the eggs present: Two divergent types of coloration, with endless variations and intermediate phases. Light type: ground color light gray or greenish gray, spotted and blotched with grayish brown or, more sharply, with sepia. Eggs of this type rehearse relationships, now with the Quiscaline Grackles, and now with the Yellowheads (Xanthocephalua xanthocephalus), or the Cowbirds (Molothrus ater). An egg in the M. 0. 0. collection has a background of pale niagara green sharply spotted with a blackish pigment which tones out to dusky drab, and is thus indistinguishable from the egg of an Agelailne Blackbird. Dark type: Ground color completely obscured by overlay of fine brown dots, or else by confluent blotches of Rood’s brown, walnut brown, or cameo brown.
Bendire (1895) writes: “The average measurement of two hundred and forty-five specimens in the United States National Museaum collection is 25.49 by 18.60 millimetres, or about 1 by 0.73 inch. The largest egg in this series measures 27.94 by 20.07 millimetres, or 1.10 by 0.79 inches; the smallest, 20.83 by 15.49 millimetres, or 0.82 by 0.61 inch.”
Incubation: Bendire (1895) states that the incubation period is 14 days. Saunders (1914) says that the eggs hatch in 12 days in Montana.
Because of the inaccessibility of most nests (high up and at the end of limber branches) that entered into my study of the species, it was possible to look into only a small number of them. Of these it was feasible to make daily inspection at only 5, of which 3 sets had 4 eggs, and 2 had 5 eggs each. One set of 4 eggs hatched in 12 days and all the others in 13 days, reckoning the incubation period from the day the last egg was laid until all were hatched. No thorough study of incubation rhythms was made, but watching females at inspectable nests revealed that they spend time on the eggs before the full set is laid. This correlates with the fact that hatching of the young (except in the set of 4, in which all hatched on the 12th day) was spread over as much of 3 days and indicates that incubation may start before the clutch is complete. The tangible facts ascertained from the few accessible nests coincided with those inferred from parental behavior at other nests .
Although the male takes no part in incubation and may even form an attachment with another female at this time, his attention does not in all cases leave the incubating female entirely. Monogamous males may spend much time on the guard perches near the nest. Polygynous males have been known to guard at two nests if the incubation periods overlap; but if one female is in Phase 1 or 2 while the other is incubating the male gives much more attention to the former (if the nest of either incubating female is destroyed she very quickly reverts to Phase 2). In a few cases the male has been seen to feed the incubating female on the nest.
Young: Data on the length of the nestling period is extremely scanty in the literature. In my study I was able to ascertain definitely the nestling period in only three instances. In each case it was 13 days, calculating the period from the day the last egg had hatched until all the young had left the nest under natural conditions. As in the determination of the incubation period the information obtained at these three nests corroborated the observations at many inaccessible nests. The male Brewer’s blackbird at the river-mouth colony was found to assist the female in feeding the young, both in and out of the nest, in 72 out of 99 monogamous nestings and 76 out of 109 polygynous ones. In the remaining cases in each category the male disappeared, or the eggs did not hatch, or the nestlings died before male attention could be determined, or there were not sufficient observations to prove or disprove male attention .
Although I was unable to carry out extended periods of watching at any one nest, periods varying from 1 to 3 hours at various nests throughout the fledging period indicate that although the female usually exceeds the male in the number of trips per hour with food, the male sometimes equals and even exceeds the female in such trips, especially in the early part of the period when the female is brooding the young. When two sets of nestlings were being fed by a polygynous male during the same hour period the combined rate for both nests might equal the maximum rate for a male feeding at only one. But males feeding at two nests were not observed to exceed this rate.
Verna L. Johnston (MS.) writes concerning a nest with five young at Live Oak, Calif. The nest was 15 feet above the ground in a deodar tree in school grounds. Both male and female fed the young at 2- to 4-minute intervals most of the time during the 9 days (May 3 to 12, 1945) that she watched them. “The male often fed the female, sometimes on a fence from which she then flew to the nest and fed the young, sometimes on the nest after feeding the young.”
At my colony nestlings that died were sometimes removed by the parents. On six occasions nestlings too undeveloped to have left the nest by their own exertions were found on the ground 50 or more feet from the nearest nest. These bore no apparent marks of having been carried by a predator. Two of these dead nestlings were actually seen being carried by the parents in flight and deposited. One of these young, which was seen being carried by the male, was newly hatched and weighed 8.29 grams. Others that were found on the ground were larger. The places of deposition were those regularly used to drop excreta taken from the nest: a pathway, pavement of the street, and the edge of the creek.
At the river-mouth colony, fledglings were observed to take initial flight of 3, 4, and 7 feet from the nest; and juveniles were fed by the male up to the 26th, and by the female to the 25th day after leaving the nest..
Females usually attempt second broods if the first is unsuccessful. There have been as many as three attempts in one season. Second broods have sometimes been raised even in cases when a first brood has also been fledged. Two broods are~ frequently raised in Oregon, according to Gabrielson and Jewett (1940).
Two females at the river-mouth colony were seen carrying nesting material for a second brood nest on the same day that they were still feeding fledglings. One female even fed a fledgling 3 days after the day on which she was first noted placing material for a second nest.
At this colony no young were observed leaving the nest later than July 7 (1943). At Bridalveil Campground, at an altitude of 7,200 feet, in Yosemite National Park, Calif., a pair were seen by Marshall (MS.) feeding nestlings as late as July 22 (1946).
Plumages: Linsdale (1936b) writes that in Nevada the down of the nestlings he examined was “nearly black, contrasting with the whitish down of red-wings.” According to Ridgway (1902) the “young” i. e., in juvenile plumage, are “very similar in coloration to winter females, but texture of plumage very different and feathers without gloss”. The immature male in first winter plumage is “similar to the adult male, but feathers of head, neck, back, scapulars, chest, and sides narrowly tipped with grayish brown (paler and more buffy on underparts.
Food: The Brewer’s blackbird feeds both on animal matter, principally insects, and vegetable matter, principally seeds.
Analysis of the stomach contents of six mature birds collected in an alfalfa and wheat area on the outskirts of Meadow, Millard County, Utah, on June 10, 1943, by Knowlton and Telford (1946) are reported as follows:
One stomach held 2 adult and 63 nymphal treehoppers, Campylenchia latipes (Say), besides other insects. Another stomach contained 8 adult and 22 larval alfalfa weevils, a clover leaf weevil, a histerid beetle and an elaterid beetle, etc. Total recognizable contents consisted of: 17 nymphal grasshoppers; the 18 Hemiptera included 1 pentatomid, 3 lygacids and 1 mind; of the 84 Homoptera, 65 were membracids, 15 were aphids including S pea aphids, and 2 leafhoppers; 57 Coleoptera, among them 19 adult and 16 larval alfalfa weevils, 2 clickbeetles, 3 white grubs, a buprestid and histerid; 1 adult Tnichopteron; 40 larval Lepidoptera; 2 larval Diptera; 10 of the 15 Hymenoptera present were ants. Three spiders also were present.
This interesting blackbird is sufficiently abundant in many parts of Utah to be of importance in the control of cutworms, grasshoppers and certain other insect pests.
The termite Zootermopsis angusticotlis has been observed by Cowan (1942) as a food of the Brewer’s blackbird in British Columbia. La Rivers (1941) while working on a program for the control of the Mormon cricket (Anabrus simplea~) in northern Nevada during the sununer of 1939, made the following observations:
This bird [the Brewer’s blackbird], in company with the Sage Thrasher [Oreescoptes montanus] and Western Meadowlark [sturnella neytecta], is one of the destructive “Big Three” of the northern Nevada cricket fields. It has been known to destroy entire bands of adult crickets, but has never been reported as working on the egg-beds. It can safely be said that each of these three species of birds is responsible for more destruction of the Mormon cricket than all the other species together. * * * However, while the blackbirds feed extensively on the crickets in lean areas, they may almost ignore them adjacent to fields where they can obtain abundant seed. In one region south of Whiterock I observed a band of approximately 200 blackbirds working on a hillside which bore a cricket population of five per square foot. After an hour’s observation I investigated their work and found, at the spot, only one attacked cricket to the square yard. Females [the birds ate only female crickets] constituted fifty percent of the cricket population, and, on this basis, the kill ratio amounted to 1 out of 22.5, a very low figure.
Knowlton and Harmston (1943), working on grasshoppers and crickets eaten by birds in Utah, examined the stomach contents of 105 Euphagus cyanocephaiws. They report “40 contained Orthoptera, including 51 adult and 9 nymphal grasshoppers in 30 stomachs; the other ten stomachs held 16 field crickets.” Bryant (1912) lists the Brewer’s blackbird as a feeder on grasshoppers during an outbreak of these insects in California, but says that it does not rank among the most important predators, judged either by the number of insects per day each bird eats or by the number of birds eating the grasshoppers. He concludes that the value of birds in controlling such insects is greater during the periods of normal insect numbers than at times of extraordinary abundance. Bryant (1911) found the Brewer’s blackbird to be an efficient destroyer of the butterfly Eugoria californiea during an outbreak in northern California in 1911.
Several authors have reported caterpillars in the diet of this species. Munro (1929) observed them feeding on “forest tent caterpillars” at Rollins Lake, British Columbia. McAtee (1922) reports the taking of canker-worms by this blackbird at three places in California where the worms were threatening prune crops .
The corn earworm (Heliot his obsoleta) has been accused of being “the most destructive insect enemy of corn in the United States” and one of the most important of the 17 species of bird to feed on this pest is the Brewer’s blackbird, according to Phillips and King (1923).
This species was seen by Murie and Bruce (1935) associating with western sandpipers (Ereunetes mauri) which were feeding on the brine fly Ephydra millbrae along a road traversing the mud flats on San Francisco Bay. The blackbirds also were “almost certainly feeding on the flies.” Bond (MS.) found Ephydra hians as an item in the diet of this bird at Moss Landing, Monterey County, Calif., in 1931 and Ephydra 8p. at Owens Lake, Calif., in 1938 .
The Brewer’s blackbird is considered by Kalmbach (1914) to be an effective enemy of the alfalfa weevil. Howell (1906) says: “Four species of blackbirds are known to consume boll weevils [in Texas], the most important of which seems to be the Brewer’s blackbird.”
Emlen (1937) says: “Blackbirds have frequently been accused of stealing almonds; but although three species, Brewer (Euphagus cyanocepkalu~), Bicolored (Agelajus phoeniceus), and Tricolored (Agelajus tricolor) were all common in the orchards, there is no definite evidence that they were feeding on almonds during the preharvest months.” Beal (1948) writes:
During the cherry season in California the birds [Brewer’s blackbird] are much in the orchards. In one case they were observed feeding on cherries, but when a neighboring fruit grower began to plow his orchard almost every blackbird in the vicinity was upon the newly opened ground close after the plowman’s heels in its eagerness to secure the insects turned up.
The laboratory investigation of this bird’s food covered 312 stomachs, collected in every month and representing especially the fruit and grain sections of southern California. The animal portion of the food was 32 percent and the vegetable 88 percent.
Caterpillars and their pupae amounted to 12 percent of the whole food and were eaten every month. They include many of those pests known as cutworms. The cotton-boll worm, or corn-ear worm, was identified in at least 10 stomachs, and in 11 were found pupae of the codling moth. The animal food also included other insects, and spiders, sow bugs, snails, and egg shells.
The vegetable food may be divided into fruit, grain, and weed seeds. Fruit was eaten in May, June, and July, not a trace appearing in any other month, and was composed of cherries, or what was thought to be such, strawberries, blackberries or raspberries, and fruit pulp or skins not further identified. However, the amount, a little more than 4 percent for the year, was too small to make a bad showing, and if the bird does no greater harm than is involved in its fruit eating it is well worth protecting. Grain amounts to ~4 percent of the yearly food and forms a considerable percentage in each month; oats are the favorite and were the sole contents of 14 stomachs, and wheat of 2, but no stomach was completely filled with any other grain. Weed seeds, eaten in every month to the extent of 9 percent of the food, were found in rather small quantities and irregularly, and appear to have been merely a makeshift.
Stomachs of nestlings, varying in age from 24 hours to some that were nearly fledged, were found to contain 89 percent animal to 11 percent vegetable matter. The largest items in the former were caterpillars, grasshoppers, and spiders. In the latter the largest items were fruit, probably cherries; grain, mostly oats; and rubbish.
The results of an investigation of the food habits of the redwing (Agelajus ~phoenieeus) and Brewer’s blackbird in California has been presented by Soriano (1931). The stomach contents of 285 Brewer’s blackbirds, taken in all the months of the year and from 15 counties in various sections of the State, were examined. The animal food taken included Coleoptera (represented by at least 13 families), Diptera, Hemiptera, Homoptera, Hymenoptera, Lepidop tera, Orthoptera, Chiopoda, and Arachnida. Cereals, mainly wheat, were the vegetable foods most taken. Other seeds found included Amaranthus, Amsinekia, Stellaria, Sorghum, Erodium, Polygonum, and RThes. “In the months when insects and vegetable food, especially cereal in the harvest season, are both abundant,” writes Soriano, “vegetable food is taken less, showing that these birds are primarily more insectivorous in food habits than vegetarian. Most of the insects taken belong to the destructive families of insects from the point of view of the farmer and fruit grower. Very few beneficial insects are taken. The destruction of these harmful insects means a great help to the farmers and growers in particular, and to consumers in general.” Most of the cereal taken is not “from newly planted seeds, for the birds take sown seeds uncovered, as also grain from pastures, barnyards, orchards and grain fields. Economically this cereal is not important and it can be considered waste grain.” The rest of the vegetable food is almost all weed seeds. “Economically, in the widest human interests,” concludes Soriano, the redwing and the Brewer’s blackbird “are beneficial, being more insectivorous than vegetarian in food habits. However, being gregarious birds, they can now and then inflict such great damage on crops that to give them full protection is not fair to the fanner whose crops are immediately threatened.”
The species as I have observed it in northern Monterey County, Calif., forages in a wide variety of open or grass covered situations. Parent birds have been seen gathering food for nestlings on the beach where the receding tide has left bits of kelp; the birds have been seen feeding on the dry parts of the beach above high tide mark, on wet sand bars at the mouth of the Carmel River, on mud flats near the river mouth, and on the grassy areas of the adjacent marsh where they mingle with pintails (Arias acuta), shovellers (Spatula clypeata), Wilson’s snipe (Capella gallina go), killdeer (Charadrius vocijeru~), and other shore birds. They feed in both green and dry pastures and grasslands (where they may or may not feed near cattle), on recently burnt-over grass areas, along the bare shoulders of highways in open country, on freshly plowed fields, on lawns and golf courses, on sidewalks, and in the gutters of streets of towns.
I have never seen them foraging in dense brushland or forested areas, although the flocks fly over such areas. During the nesting season, at least, some foraging is done among the needles of the pines in the colony. For example, four times in three seasons I have seen birds poking into the insect spittle in the pines. One bird was seen carrying insects with spittle to nestlings. Dr. Kathleen C. Doering, of the Department of Entomology of the University of Kansas, identified specimens collected from similar spittle masses in the same tree as Aphropliora.
I have also seen flycatching tactics on numerous occasions when the birds took short flights from the ground to capture a flying insect. Such sallies are also made from telephone wires.
Grinnell, Dixon, and Linsdale (1930) mention the distance from its nest the bird will forage to feed nestlings. Parent birds gathered food from the ground on a chaparral-covered slope half a mile away from their nest on the edge of a lake. At the river-mouth colony parents range some distance for food. The maximum recorded was on May 17, 1944, when birds went to a feeding tray just half a mile away to get food for nestlings 4 and 5 days old and for fledglings out of the nest.
The species seems capable of shifting quickly from one foraging situation to another, e. g., the instance mentioned by Beal (1948) of a flock leaving cherries to follow the plow. This trait has been commented on by Winton Wedemeyer (MS.) and others. The bird is commonly observed following various tillage operations. R. M. Bond (MS.) reports that in 1939, 1940, and 1941 Brewer’s blackbirds “followed the cultivating equipment near Somis, Ventura County, Calif., often in hundreds. Available insect specimens turned up by the plow were few, and the great majority of individuals were larvae of the wireworms Limonius californicus and Melanotus longulus, both serious agricultural pests.”
Observers have reported seeing the bird turn over chips of dry cowdung in pastures. Linsdale (1938) writes of a male that “turned over pieces of cow manure with its head and looked beneath them for food.” I have watched this action a number of times. It is usually accomplished by the bird putting its bill beneath the chip and flipping it over; sometimes the bird nudges the dung forward as it lifts, thus overturning it. The bird inspects both the newly exposed ground and the underside of the chip and takes food from both places. One piece of manure turned over measured 98 by 70 by 30 millimeters and weighed 33.85 grams. Sometimes the birds poke vigorously into horse manure, flipping pieces aside with the bill. They turn over other objects such as small pieces of wood, clods of earth, and even small stones. One piece of wood overturned by a blackbird measured 95 by 45 by 13 millimeters. Occasionally the bird thrusts its bill underneath and then opens the bill to pry the object up, overturning it with a forward and upward motion. One bird enlarged a hole in soft mud by inserting the closed bill and then opening the bill. It then picked something out of the hole. Once a male bird was seen digging vigorously into the turf of a golf course, pulling out bits of dirt which it flicked off the bill; finally it pulled out a whitish object about 50 millimeters long, possibly an insect larva.
La Rivers (1941) describes the method of eating Mormon crickets as follows:
The Brewer’s assault upon the cricket is confined entirely to the females, which the birds covet for their eggs. These they take by splitting the dorsum of the abdomen transversely along the soft membranous tissue between the sclerites, a feat accomplished by grasping one end of the body in the bill, the other in a claw, and tugging; some go to less trouble and merely tear the head off, pulling with it the entire abdominal, and much of the thoracic, contents, which are all consumed. An unexplained habit of these birds is their snipping off of the female cricket’s ovipositor, something they quite frequently do.
I have observed blackbirds feeding in water that reached as high as the belly feathers. Semiaquatic feeding has been very well described by Richardson (1947):
Manzanita Lake on the campus of the University of Nevada has extensive growths of the water-weed Anacharis cenedensis. Each year by the end of May the new growth of this plant forms a dense mat an inch or less below the water surface. For several years now both Red-winged (Agelajus phoeniceus) and Brewer (Euphagus cyanocephalus) blackbirds that nest in the vicinity of the lake have been observed feeding on insects associated with the waterweed. The blackbird, alight on the plants, the water usually coming to the middle or upper part of the birds’ tarsometatarsi. Typically, the wings are then fluttered as the bird hops two or three feet to new vantage points. Less often a bird will walk, even a distance of thirty feet, without moving the wings. The tail, as appeared to be the habit in one individual especially, may be submerged and possibly pressed against the underwater vegetation for support.
The most readily visible food obtained, and certainly the major item for a period of weeks in the early summer, is recently emerged damselflies. The nalads of this insect crawl to the surface of the waterweed and metamorphose on projections just above the water. The blackbirds have been seen repeatedly catching these newly emerged and still pale and flightless adults.* * *
Brewer Blackbirds of both sexes have been seen several times walking and feeding on pad-lily (Nymphaea) leaves, even one leaf serving to hold up a bird. On two occasions, once on the Truckee River and once on the Carson River, Brewer Blackbirds have been seen hovering over open water and snapping food from the surface. A male of this species was seen similarly to obtain a large piece of bread in Manzanita Lake and carry it to shore to be eaten .
Both Ken Stott, Jr., and A. D. DuBois (MSS.) describe Brewer’s blackbirds soaking popcorn in water before eating it. I have often seen them soak bread in a bird bath or, at the river-mouth colony, in the water of the marsh.
When mixed flocks of redwings and Brewer’s are seen feeding on the ground a difference can be noted in the angle at which the tails are cocked; those of the redwing are held obviously higher. In a large mixed assemblage the difference is quite noticeable.
The movements of a foraging flock of Brewer’s blackbirds has been well analyzed by Mulford (1.936) as a combination of the walking of individuals in zigzag movement but all progressing slowly in the same general direction, and the flying up and realighting in front of the flock by those which had been left walking in the rear. Dawson and Bowles (1909) have commented that this flying up to the front of the foraging flock is sometimes a constant motion and when a large assemblage is present it creates a rolling, or surging, effect, as the mass of the birds moves over a large field.
Neff and Meanley (1957) have analyzed the winter food in Arkansas.
Behavior: The gait of the Brewer’s blackbird is usually a walk, accompanied by short forward jerks of the head. When the bird runs there is no jerk. MuLford (1936) outlines the process of taking two walking steps as follows: “1. Head is thrust forward as one leg and foot are lifted. This moves the center of balance forward. 2. Leg and foot are brought forward. 3. Head is pulled back as body is brought forward by step and as foot is set down on ground. 4. The sequence of movements is repeated with other foot. The result of this is that the bird moves forward in a series of movements rather than in one continuous movement. The walk is jerky.”
Mulford also comments that there is no characteristic formation to the flock when in flight but it is an “amorphous mass,” either compact or spread out; of rounded form or with irregular margins; in one big group, or more or less divided into subgroups.
The speed of flight has been measured by Rathbun (1934). A flock was paced from a car for one mile and was found to fly at 27, 35, and 38 miles per hour. There was no wind.
In the region of Carmel, Calif., the Brewer’s blackbird uses principally two types of growth for roosting, patches of tules in the marsh, where they associate with the redwing, and thick tufts of foliage of the Monterey pine, a situation similar to that which they use for nesting.
In late summer, fall, and winter I have noted late afternoon flight lines from feeding areas up Carmel Valley toward roosts at the mouth of the Carmel River and in the Carmel business district. The birds frequently gather at a dairy farm 3% miles east of the business-district and river-mouth roosts. From this point, as well as from further up the Valley, a number of flocks of Brewer’s and mixed flocks of Brewer’s, redwings, and tricolored redwings fly westward down the Valley. The number of Brewer’s in either mixed or pure flocks has been found to range from 40 or ~50 to 300 birds. The westward flight line has also been noted from a point 2 miles further down the Valley than the dairy farm, and a corresponding eastward movement in the morning has been seen there.
At both the business-district and river-mouth areas the flocks of Brewer’s blackbirds gather on electric wires before roosting time and occasionally fly down to forage. The actual flight to the roosting places in the pines is made individually and at irregular intervals, the birds lighting first on the branch tips then working their way into the thick parts of the foliage. There is often considerable moving about in the foliage and bickering for positions, and considerable utterance of various calls, especially the kit notes.
On November 17, 1943, a female at the river-mouth colony roosted in a tuft very close to her nest situation of the preceding spring. On October 30, and December 28, 1944, the same female roosted in a similar tuft of the same tree. Her nest of 1944 was also within a few feet of this roost.
In the morning the birds fly out individually and at irregular intervals from the roosting tufts in rapid, zigzag flight and gather on the wires. Those leaving the tules sometimes fly directly eastward up the valley. Some leave the pines at the river-mouth and fly toward the business district. Morning observations in the business district show large gatherings on the wires, some birds coming from tufts of the street pines, and others, possibly, from the river mouth. After an interval on the wires, a large flock has been seen (December 12, 1947) taking flight eastward and passing out of sight. This line of flight would carry them up the Valley along the flight lines mentioned above. Some of the birds in the business district, as well as some at the river mouth, remain to forage locally.
Indications are that in this region the Brewer’s blackbird goes to roost earlier and leaves the roost correspondingly later than some other species in the area. The redwing has been heard calling up to 10 and 12 minutes after the last Brewer’s notes were heard. (The female noted above went to her roosting tuft, silently, 13 minutes before the last redwing note was heard from the adjoining marsh, October 30, 1944, and 14 minutes before the last bush-tit (Psaltriparus mtnimus) notes were heard on November 17, 1943.) In the morning, also, several species of passerines have been heard before the first calls of the Brewer’s were detected. Golden-crowned sparrows (Zoiwtrichia coronata) have been heard making their first call 21 minutes before the first Brewer’s blackbird notes .
Similar diurnal rhythms between pine roosting places at Berkeley, Calif., and distant foraging places have been described by Mulford (1938). Stott (MS.) furnishes the following notes from San Diego. Calif., where he watched a wild flock at the zoo:
“While their roosting place changes from time to time (bamboo clumps, palm crowns, Grevillea trees, etc.) they follow a fairly stable pattern in their diurnal activities about the pool. Each morning they appear first on a telephone line which stretches across a canyon north of the Mirror Pool area. Suddenly a small group at the south end of the line drops to the ground on a macademized road; there it is shortly joined by another group and another, until the entire flock has forsaken the wire. Its members strut up and down the road in search of scattered popcorn. In the late afternoon the blackbirds begin to congregate near the pool until they form a more or less compact flock. Subsequently, they fly in small groups back to the telephone wire on which they had congregated earlier in the day. Their next move is a unified one and takes them to their current roosting place.”
Lockerbie (MS.) mentions the use of cattails for roosting in the Salt Lake City, Utah, region. Bassett (1931) found them using floating duck-hunting blinds, covered with eucalyptus boughs, that were anchored nearly a mile from the high tide line in San Pablo Bay, Calif.
Voice: In the belief that there is no really satisfactory way to syllabify the notes of this species, I have merely attempted a tentative and, it is hoped, suggestive rendering of the utterances. In some of the cases the associated activity of the bird is mentioned, together with the function of the call, when this is known, in order to aid the reader in identifying the notes. Most calls are subject to considerable individual variation but are always identifiable as one of 13 types, that can be grouped in two broad categories: single utterances and series utterances.
The single utterances are either short or long and drawn out. Among the short, incisive, single-syllable utterances are the following sounds: Tschup: a “scolding” note uttered when there is a disturbance near the nest or young, or in other situations of excitement. A “flocking” note: uttered when groups take off and fly in flock formation, that is shorter, higher, less loud, and with less s sound and more t sound than tschup. Tup: uttered by adults when approaching the nest with food; more frequently used when approaching the place where a young fledgling is; but also used by adults when flying with older fledglings following; it is shorter, softer, lower, more muffled than the tschup. A “location” note: uttered by the fledgling during intervals between food-bearing visits of the parents; like tschup, but weaker, it has a shorter vowel sound and a more nasal quality. The “squawk”: a low, scratchy note uttered when one bird makes contact with another, it is used when one bird grabs another in fighting, when a blackbird is caught by a hawk, and also used when a blackbird dives at a hawk; Mulford (1936) writes it chaw .
Long drawn-out, single utterances, of one or more syllables, include the following: Squeee: a very loud hoarse whistle with decided upward inflection (this note and tee-uuu, described below, carry farther than any of the other calls). Schl-r-r-r-up: : a comparatively subdued, toneless, whirring gurgle, aptly described by Mulford (1936) as “a rush of air without vocal accompaniment”; this call and the preceeding one are subject to considerable individual variations (for the associated activities see under “Spring” and “Courtship”). Tee-uuu: a loud, clear, thin whistle with decided downward inflection, that sometimes becomes pit-eee or tsee-eur, but in all cases with the second. syllable lower in pitch than the first; it is the only clear whistled note in the repertory and functions as a “warning” note (see under “Enemies”).
The second major category, series utterances, includes short notes uttered in series, sometimes with a definite rhythm, as follows: Kittit-tit-tit, etc: sometimes regular in delivery, sometimes irregular, varying in quality of tone, intensity and rapidity of utterance; at times it sounds more like kit -r-r kit-r-r, when it has a decided rythmic effect; it is used both in the female generalized display and in belligerent encounters, by males (rarely) when bickering over food, and is frequently heard accompanying bickering at the roost (when the sex of the bird cannot always be identified). The female copulatory note: a soft, low, steady series of tapping notes, very different from any of the other utterances: is used in the female pre-coitional display (see under “Spring” and “Courtship”). Chug-chug-chug, or tucker tucker-tucker, or tit-tit-tit: used by males accompanying the elevated tail display (see under “Spring” and “Courtship”); sometimes these utterances resemble the kit notes. Peeping sounds: made by young nestlings. Tut-utz-utz: a low, hoarse, scratchy series of rhythmic notes, the “begging” notes of older nestlings and of fledglings; when the parents are away foraging the fledgling utters the “location” note, but when the adult arrives the young bird changes to this “begging” note in anticipation of being fed.
Field marks: The species most easily confused with the Brewer’s blackbird in the field are the redwing and tricolored redwing, the rusty blackbird (Euphagus carolinus), the bronzed grackle (Quizealus quiscula), and the cowbird (Molothrus ater). Peterson (1941) says that the male rusty blackbird in summer plumage has “dull greenish instead of purplish head reflections [as in Brewer’s]. The iridescence is almost lacking [and is] not noticeable as in the Brewer’s Blackbird or the Bronzed Grackle.” The rusty and Brewer’s blackbirds are about the same size but the bronzed grackle is noticeably larger and has a “longer tail, which is somewhat wedge-shaped.” The female Brewer’s has a dark brown iris in contrast to the pale yellow iris of the female rusty blackbird. In winter the female Brewer’s blackbird does not have the rusty wash, as do rusty blackbirds of both sexes. But the immature male Brewer’s in the first winter plumage, according to Ridgeway (1902), has the “feathers of head, neck, back, scapulars, chest, and sides narrowly tipped with grayish brown.” There is the possibility that in this plumage, also, the male might be confused with the male rusty blackbird in winter plumage. But the tipping is more grayish and less rusty brown. The male redwing and tricolored redwing are obviously distinct from the Brewer’s. Hoffman (1927) points out the distinctive marks for females: “The unstreaked breasts distinguish the Brewer Blackbirds from female Redwings [and also, it may be added, tricolored redwings], and the greater size, darker plumage and long, sharp-pointed bills distinguish them from the female Cowbirds. The yellow (apparently white) eye and long sharppointed bill distinguish the male Brewer from the male Cowbird.”
Enemies: La Rivers (1944), reporting on one nesting season of Brewer’s blackbirds near Reno, Nev., found that 107 nests held 521 eggs, 205 of which resulted in fledglings that left the nest safely, a mortality of 60.65 percent. “Twenty-three eggs were known to be sterile, but other sterile eggs were obviously among those which disappeared without known cause. The total number of eggs and nestlings unaccounted for because of unknown predation, amounted to 83, but the remaining 233 could nearly all be ascribed with certainty to one of 23 known factors, 21 of which were biologic, the other two climatic i. e., wind and hail].”
Among the biological factors which accounted for 86.07 percent of the mortality, predation was preeminent. Those predators that were “persistent bird and egg feeders” were: Scrub jay (Aphdocoma coerulescens), American magpie (Pica pica), crow (Corvus brachyrhynchos), bridled weasel (Mustetafrenata), western ringtail (Bassari.scus astutus), desert bullsnake (Pituophic catenijer), striped racer (Coluber taeniatus), and blue racer (Coluber constrictor). Those predators that could only be “classed as occasional opportunists” were: Sharp-shinned hawk (Accipiter st ri atus) , horned owl (Bubo virginianus) , Steller’s jay (Cyanocua stelleri), Piute ground squirrel (Citellus mollis), Beechey ground squirrel (Citellus grammurus), Sierra mantled ground squirrel (Cabspermophilus chrysodeirus), Douglas chickaree (Sciurus douglasi), striped skunk (Mephitis mephitis), and Great Basin rattlesnake (Crottilus viridis).
“Protective factors” included the floral elements; some types of plants used afforded better nest protection than others. Also the height of the nest emplacement was important; 57.94 percent of the nests were placed 5 feet or less above the ground, 32.71 percent from 5 to 10 feet, and 9.34 percent above 10 feet. It was found that “mortality progressively increased” from the highest to the lowest. Still another protective factor was the tactics of parent birds in driving off predators. However, in some cases, La Rivers believes, “noisy, quarrelsome, conspicuous birds” attracted predators to their nests.
Bond (1939) in an examination of the remains of prey items from beneath five nesting sites of the prairie falcon (Falco mexicanus) in the region of the Lava Beds National Monument, Calif., found two Brewer’s blackbirds at one eyrie, none at the other four. He found remains of eight Brewer’s blackbirds beneath the nesting site of a duck hawk (Falco peregrinus). A large number of pellets of the homed owl and barn owl (Tyto alba) were also collected by this author from beneath roosts in the same region. Two collections were made, one on August 12, 1937, at which time only those pellets “were taken that seemed, on the basis of state of preservation, to have been cast later than the preceding winter.” At the time of the second collection November 5, 1937, only those were taken which seemed certainly to have been deposited since the August collection. In the first collection the remains of 12 Brewer’s blackbirds were found among a total of 3,391 items of bird, reptile, mammal and insect remains, which amounted to 0.0035 percent of the total. In the second collection two Brewer’s blackbirds were found out of a total of 994 bird and mammal remains, or 0.002 percent. Considering the effect of predation on birds by both hawks and owls in this area, Bond states that the Brewer’s blackbird was among the five species of birds most often killed by hawks. In the combined owl pellet collections the total of 14 Brewer’s blackbird items out of a total of 100 bird items puts it among the 7 bird species that were represented by more than 5 percent. But most of the birds taken by both hawks and owls were common to exceedingly abundant in the area (the Brewer’s blackbird was in the latter class). Bond concludes “it is quite clear that none of the species is endangered, or probably appreciably reduced in numbers, by either the hawks or owls.”
Sumner (1928) reports finding a headless young Brewer’s blackbird on two different days in a tree cavity occupied by young screech owls (Otus asio) at Claremont, Calif. W. H. Beble (MS.) found remains of this blackbird near the nest of a short-eared owl (Asio lammeu.s) in Utah.
Bond (MS.) writes that he has “seen both Cooper’s hawk [Accipiter cooperil and the pigeon hawk Falco columbarius] catch a Brewer’s blackbird, the former on the ground and the latter in the air.”
In Carmel Valley, Calif., on December 15, 1942, I witnessed the capture of a Brewer’s blackbird by a sharp-shinned hawk. A mixed flock of about 500 redwing, tricolored, and Brewer’s blackbirds were alternately perching on power wires and flying down in small groups to feed in straw stubble near some horses. The hawk was first noticed pursuing the blackbird, which it seemed to have singled out from a group of about 300 birds flushed from the stubble. The hawk followed the blackbird in a twisting and turning flight; there was a “squawk” from the blackbird as it was caught. The raptor then flew to a nearby thicket, seeming to labor in flight with the blackbird in its claws. The whole chase and capture and removal to the thicket took place not more than 10 to 15 feet above the ground and lasted only a few seconds.
The usual warning note, tee-uuu, is given when a hawk flies over the colony. It is uttered by other members of the flock when a hawk is pursuing one of them. It may also be used when some large bird is merely passing by, even high overhead. The chorus of schlr-r-r-up, aquee and kit-tit-tit of the nesting colony suddenly stops as one or two birds utter the warning note and others join in. Looking up one may see a hawk, a crow, a night heron, or even a large gull passing over. When it has gone by the tee-uuu ceases and the chorus recommences. This alarm has been noted on two occasions when airplanes have passed over. On at least four occasions I have heard this note when a duck hawk has soared overhead or flown by; I have also heard it when sharpshins have attacked or have merely flown by and on numerous occasions when crows have flown past.
R. M. Bond (MS.) observed the reactions of a flock of Brewer’s blackbirds to the attacks of a marsh hawk (Circus cyaneus) as follows: “For about 15 minutes, during an extremely cold spell in February 1936, I watched about 25 Brewer’s blackbirds feeding on spilled grain on the snow. I was seated in a parked cal’ a few feet away. During the whole of this time, an adult male marsh hawk tried to catch one, and at each strike the blackbirds in danger would shift a couple of feet, easily dodging the raptor, pick up a few more grains and dodge the next blow. The blackbirds rose only a few inches from the ground each time. None was ever caught, though there were some near misses, and I suppose the hawk succeeded eventually.” Bond (1947) has found the remains of a Brewer’s blackbird at a marsh hawk’s nest near Watsonville, Calif .
“It is a well known trait of the Brewer Blackbird to badger large birds such as hawks and crows,” writes Grinnell and Storer (1924). The list of those animals harried or mobbed by this species is extensive and includes the great blue heron (Ardea herodias) (Bond, MS.), snowy egret (Egretta thula), white-tailed kite (Elanus leucurus), homed owl, pygmy owl (Glaucidium gnoma), weasel, gray squirrel (Sciurus griseus), cats, dogs, and humans. Attacks by the blackbird may be made singly or in groups. An incident of an attack on a sparrow hawk (Falco sparverius) taken from my notes will suffice to illustrate the manner of single attack on a flying bird: “Monterey County, June 13, 1948: A male Brewer’s swooping at a sparrow hawk, seemingly making contacts on the lower back or tail. Would fly rapidly from behind and a little above, catch up to the hawk, sail down on it and seem to make contact uttering the squawk at the same time. At this moment the hawk would twist in flight, seemingly in order to evade the blackbird.” These attacks, although seen several times on that day, did not seem to extend very far beyond the limits of the nesting colony. La Rivers (1944) mentions a sparrow hawk killing a Brewer’s blackbird that was harrying it. Allan R. Phillips (MS.) says that on June 14, 1936, he “took a young male from a sparrow hawk that was carrying it away, pursued by adult blackbirds, so Faico sparvermus is an occasional enemy of the young.”
The sharp-shinned hawk has been observed to be mobbed by blackbirds. The warning note was uttered by several members of the river-mouth colony on May 23, 1945, as several other Brewer’s blackbirds pursued a sharp-shinned hawk flying away and at some distance from the colony. A group of about five redwing and/or Brewer’s pursued a pigeon hawk, on September 25, 1945, at the rivermouth colony. At first a much larger group of about 25 of both species of blackbirds hovered about a pine where the hawk was perched. When the hawk took flight the five took after it, pursuing from a little above the hawk. Once the hawk turned and swooped upward toward its pursuers, who immediately turned back for a short way, but when the hawk resumed the general direction of its flight, the blackbirds again took up the chase until they were out of sight.
When a subject for mobbing, as a gray squirrel, for instance, appears m a tree near a nest at the colony the effect on a large part of the colony is almost instantaneous; there is a sudden outburst of rapidly repeated tsckup notes and many birds gather nearby. Some of them swoop at the animal and even strike it. Even though the attack is strenuous and prolonged it is not certain that it has any effect in routing the squirrel. I have no proof that the squirrel preys upon the eggs or nestlings, but since the nests are often built resting on one or more cones, the nests could, of course, be destroyed by the squirrel in taking cones.
On two occasions, at the river-mouth colony the birds were seen harassing weasels. One of these was on May 13, 1947, when 35 redwing and Brewer’s blackbirds were seen hovering about 5 or 6 feet above the weasel and following it as it ran over the marsh in which the redwing colony was situated, adjacent to the Brewer’s colony. The Brewer’s uttered loud, excited isehup notes, sometimes lighting on the tule stems or the grass as close as 5 feet behind the mammal. The cloud of noisy birds thus followed the weasel for about 150 feet, until it disappeared.
Death along highways has been considered by several writers. Robertson (1930) covered the same 30.3-mile route over paved and unpaved roads 287 times during one year. He found 136 dead birds of at least 27 species, 9 of which were Brewer’s blackbirds. R. M. Bond (MS.) remarks that he has been impressed by the fact that, in his experience, Brewer’s blackbirds almost invariably fly clear of approaching cars on the highways, in contrast to the frequency with which redwings and tricolored redwings are struck. He counted 156 traffic casualties for the three species on roadsides in Oregon, California, and Nevada during his travels in those States in the years 1935 to 1937. Only four of these casualties were Brewer’s blackbirds. The proportion of Agelaius would have been even higher if counts had been made where redwings and tricolored redwings were crossing a highway from nesting colony to feeding grounds.”
Baumgartner (1934) records only one Brewer’s blackbird among the 353 specimens of 42 species of birds recorded as automobile casualties during two trips by car to the Western States, totaling 16,700 miles, in the summers of 1927 and 1929.
Other accidental causes of death are recorded by Lansdale (1931, 1932), who found this bird to be an indirect victim of “pest control” programs in California, where it eats poisoned grain put out for ground squirrels; and by Lincoln (1931), who mentions two banding returns of Brewer’s that were killed by flying into structures.
The Brewer’s blackbird is parasitized by the cowbird. Friedmann (1929) in discussing the host species of the cowbird writes: “Bendire thought this bird was only occasionally imposed upon, but subsequent observations have shown it to be a common host of the Cowbird in the plains and prairies of the west. A. A. Saunders (Auk, XXVIII, no. 1, Jan., 1911, p. 40), writing of the Cowbird in Gallatin County, Mont., says, ‘I have found their eggs more often in the nests of Brewer’s blackbird than any other species,’ and, in the same paper, says of the Brewer’s blackbird, ‘a large percentage of their nests contain Cowbird’s eggs.’ Cowan (MS.) writes that on two occasions he has found nestlings of Brewer’s blackbird infested with Protocalliphora. Dr. Canton M. Herman, parasitologist for the California Division of Fish and Game, identified a flea from an abandoned nest at the river-mouth colony in 1945 as Dasypsyllus gallinulae.
Fall and winter: In the Salt Lake region of Utah the bird is most abundant during the winter months, according to Lockerbie (MS.), and Behle (MS.) says, “it congregates in winter in the valleys along the Jordan River, in Utah, at ranches where livestock is fed and at dumps and feed yards; there it occurs in great flocks numbering 100 to 1,000 individuals.” In the Rockport region of Texas, writes Mrs. Jack Hagar (MS.), “many of this species winter in cut-over fields with redwings, cowbirds, and great-tailed grackles,” but she believes that “great numbers go on south” of Rockport to winter, as the flocks are larger in spring and fall. In the Houston region, according to G. G. Williams (MS.), “it arrives, usually, within a few days of November 1, and disappears in the last half of April. It frequents the grazedover areas of our wide, flat, treeless coastal plain, as well as the stubble fields of the great rice farms that occupy huge areas here. It is almost never seen in localities where trees predominate. In the northern parts of Harris County (of which Houston is the county seat), where the coastal plain gives way to forest, the species becomes less and less common, and is replaced by the rusty blackbird.” Lowery (MS.) writes: “I would regard the Brewer’s blackbird as a regular and fairly common winter visitor to southern Louisiana. They seem to be more common in the vicinity of ponds and sloughs which border cane fields and other open situations. I do not believe they are quite as numerous as the rusty blackbird, but they are nevertheless a very prevalent Louisiana winter bird.”
In the fall and winter, the Brewer’s blackbird is especially gregarious, associating in flocks composed not only of its own kind but also of other icterids. However, since I have always found it nesting in some sort of colony organization, it might be considered more or less gregarioua the year around, in the Cannel region, although the size of the foraging and roosting flocks is much greater in fall and winter. The young, when first beginning to fly freely but while still depending on the parents for at least some of their food, flock together with other adults. These flocks soon associate with redwings and fall sojourning tricolored redwings. In large aggregations of the three species the Brewer’s are generally outnumbered by the other two combined .
Color-banded Brewer’s were found to wander to places as far as 6 miles north, 4~4 miles east, 6 miles south, and 4 miles northwest of the banding station at the mouth of the Carmel River. During the fall and winter the diurnal rhythm mentioned under “Behavior” is noticed, although it seems that not all birds follow this pattern rigidly.
In fall and winter the color-banded birds of the river-mouth breeding colony can be found at other colony areas, and birds that bred at these other areas may also mix with the flock at the river mouth. But there is always a nucleus of the locally breeding birds to be found at the colony.
In the months of September and October, and occasionally in November, at the river-mouth colony, there is a mild recrudescence of what I have called pairing behavior (see “Spring” and “Courtship,” above). There are instances of temporary segregation into pairs, walking and flying about together (the female generally leading in flights); mutual display; occasional displacement by the male of another male alighting near the female; and occasional darts and chases. Three females which had bred in the colony the preceding spring made one trip each with nesting material to the vicinity of their former nest sites (September 25, and October 5, 1945, and September 14, 1947). With but a few exceptions these eases of pairing behavior involved individuals that had been paired the previous spring, and some that had remated for two or more of the preceeding breeding seasons. However, most of these pairing performances were not of long duration, and on many days of observation none at all was seen. As compared to spring the activities never seemed as fully developed, and on days that they were observed fewer pairs were engaged in them.
For much of the fall and winter season pairs of the previous spring, or those which had remated for one or more of the preceeding seasons, might not even be seen in the same flock. When they did appear in the same flock, they did not behave as a pair, except on the occasions of “recrudescence,” as mentioned. Probably, therefore, it should be stated that even though the pairs remate on successive seasons, they do not maintain a pair bond continuously through the nonbreeding season. However, since the re-pairing of the male and his primary female in successive breeding seasons is more than a matter of chance (42 out of 45 possible cases),it might be stated that a true pair bond exists over a period of years in the Brewer’s blackbird and that this breaking of the bond in the nonbreeding season should be considered as only an interruption.
No migration trends were indicated from the 318 individuals that I color-banded at Carmel, on the central coast of California. Most of those birds that survived a full year or more were found in the region in both winter and summer. However many of the banded birds that did not breed in the river-mouth colony could not be kept track of, and their exact status in all seasons was not always known. The wandering of the blackbirds over a larger area (about 12 miles in diameter) in the nonbreeding season made careful checks difficult.
There may be indications of a differential sex migration in this species. Bendire (1895) states that the “birds wintering along our northern border appear to be nearly all adult males.” Gabrielson and Jewett (1940) say that in Oregon “the bird is present through the winter in small flocks composed mostly of males.”
Range: Western and south-centi al Canada to Mexico and the Gulf coast.
Breeding Range: The Brewer’s blackbird breeds from southwestern, central, and southeastern British Columbia (Comox, Fernie), central Alberta (Grimshaw, Lesser Slave Lake), central Saskatchewan (Carlton, forks of the Saskatchewan), southern Manitoba (Duck Mountain, Shoal Lake), northern Minnesota (Crookston, Ribbing), western Ontario (Port Arthur) and northern Wisconsin (Hayward, Oconto, Green Bay); south to northwestern Baja California (La Grulla, San Rafael), central-southern and central-eastern California (Kenworthy, Saline Valley), southern Nevada (Lincoln County), southwestern and central Utah (Meadow, Pine Valley, Parleys Park), central Arizona (Flagstaff, Marsh Lake), western and central-southern New Mexico (Fort Wingate, Manhill), northern Texas (Canyon, Vernon), Oklahoma (Gate; casually Creek County) Kansas, northern Iowa, southern Wisconsin (Belleville, Walworth County), northeastern Illinois (Wauconda, Northfield), northwestern Indiana, and southwestern Michigan (Kalamazoo County). Summer specimens have been taken farther north in British Columbia (Kathlyn Lake, Fran~ois Lake), Alberta (Banif, Deer Mount), and Saskatchewan (Prince Albert).
Winter Range: Winters from southwestern British Columbia (Vancouver), northern Washington (Bellingham Bay), central Alberta (casually, Camrose), central-eastern Montana, central Oklahoma, Arkansas (Fayetteville, Stuttgart), southwestern Tennessee (Memphis), southern Mississippi (Saucier, Gulfport, Tupelo), Alabama, Georgia (casually, Atlanta, Athens, Augusta), western North Carolina (casually, Asheville) and western South Carolina (casually Clemson, Chester); south to southern Baja California, Michoac4n (P~tzcuaro), Qaxaca, central Veracruz (Orizaba, Las Vigas), and the Gulf Coast, casually east to western Florida (Panama City).
Casual Tecords: Casual in northern Ontario (Lake Attawapiskat), northeastern Indiana (Ligonier) and northwestern Ohio (Spencer, Jerusalem Township).
Accidental in Keewatin (Baker Lake).
Migration: Early dates of spring arrival are: Indiana: Elkhart, March 19. Ohio: Lucas County, April 3. Iowa: La Porte, March 8. Michigan: MeMillan, April 29. Wisconsin: New Richmond, March 24; Milwaukee, March 27. Minnesota: Elk River, March 15 (average of 8 years for southern Minnesota, April 13); Foseton, March 24 (average of 7 years for northern Minnesota, April 13). Oklahoma: Caddo, February 26. Kansas: Onaga, February 20 (average of 23 years, April 10). Nebraska: Alexandria, February 26. South Dakota: Vermillion, March 9; Sioux Falls, March 26 (average of 4 years, April 4). North Dakota: Cass County, March 24 (average, March 29); McKenzie County, April 12 (average of 9 years, April 18). Manitoba: Treesbank, March 20 (median of 50 years, April 9). Saskatchewan: Sovereign, March 8; South Qu’Appelle, March 26. New Mexico: Clayton, March 7. Arizona: Tombstone, February 13. Colorado: Boulder, March 25; Fort Morgan, April 8. Utah: Ogden, March 23. Wyoming: Wheatland, March 10; Cheyenne, April 2. Idaho: Rupert, March 29. Montana: Fortine, March 20; Alberta: Glenevis, April 8; Camrose, April 9 (median of 12 years, April 20). California: Big Creek, March 2. Oregon: Weston, March 1; Pinehurst, March 5. Washington: Pullman, March 17. British Columbia: Vancouver, March 18; Okanagan Landing, March 22 (median of 13 years, April 2).
Late dates of spring departure are: Veracruz: Las Vigas, April 5. Durango: Rie Sestin, April 14. Coahuila: southeastern Coahuila, April 25. Baja California: Santa Catarina Landing, May 14. Florida: Vernon, April 8. Georgia: Athens, April 9. South Carolina: Clemson College, April 17. North Carolina: near Asheville, April 12. Mississippi: Gulfport, April 5. Tennessee: Johnson City, April 20. Kentucky: Woodford County, May 12. Missouri: St. Charles, April 26. Indiana: Ligonier, May 18. Ohio: Toledo, May 2. Iowa: Sioux City, May 19. Michigan: McMiIlan, May 21. Texas: Commerce, May 7. Oklahoma: Oklahoma City, April 25. New Mexico: Silver City, May 15. Arizona: Fort Huachuca, May 8. California: Fresno, April 30; Death Valley, April 29.
Early dates of fall arrival are: California: Fresno, September 7.
Colorado: Fort Morgan, September 9. Arizona: Tucson, September 18. New Mexico: Koehler Junction, August 20; Silver City, Sep ternber 1. Nebraska: Belvidere, August 31. Kansas: Onaga, September 10. Oklahoma: Norman, September 25. Texas: Somerset, October 4; El Paso, October 13. Michigan: MeMiHan, July 23. Iowa: Sigourney, August 20. Illinois: Chicago, September 13. Missouri: Freistatt, November 7. Tennessee: Memphis, November 5. Mississippi: Saucier, November 9. Delaware: Bombay Hook, October 22. North Carolina: Swannanoa, November 14, South Carolina: Dale, November 25. Georgia: Atlanta, November 14. Sonora: San Pedro, September 15 .
Late dates of fall departure are: British Columbia: Cranbrook, November 26; Okanagan Lake, November 22. Washington: Blame, November 27. Oregon: Weston, December 14; Pinehurst, October 25. California: Big Creek, November 23. Alberta: Morrin, December 1; Glenevis: October 26 (median of 17 years, August 28). Montana: Chouteau County, October 19. Idaho: Rupert, November 24. Wyoming: Laramie, December 9; Yellowstone Park, November 20. Utah: Ogden, November 16. Colorado: Fort Morgan, November 30; Beulah, November 3. Arizona: Tombstone, November 28. New Mexico: Aztec, December 9. Saskatchewan: Wiseton, November 27; McLean, November 21. Manitoba: Treesbank, November 22 (median of 47 years, October 31). North Dakota: McKenzie County, December 6; Cass County, November 28 (average, November 1). South Dakota: Sioux Falls, November 28 (average of 7 years, November 14). Nebraska: Valentine, November 3. Kansas: Onaga, November 27 (average of 22 years, November 13). Oklahoma: Oklahoma City, November 29. Minnesota: Minneapolis, November 30 (average, November 3); St. Vincent, October 20. Wisconsin: St. Croix County, November 22. Michigan: Blaney Park, October 30. Iowa: Wall Lake, November 18. Illinois: Chicago, October 27.
Egg dates: Alberta: 16 records, May 20 to July 2; 8 records, May 26 to June 5.
California: 288 records, March 29 to July 10; 160 records, April 29 to May 30.
Nevada: 18 records, May 12 to June 10; 9 records, May 20 to May 26.
North Dakota: 14 records, May 25 to June 4 .
Oregon: 29 records, May 12 to July 8; 16 records, May 20 to June 5.