The Brewer’s Sparrow breeds in arid sagebrush shrublands, and can survive for weeks without water on a diet of seeds. Juicy insects or standing water are welcome, though this survival ability may help the Brewer’s Sparrow get through a short period of difficult drought.
Brewer’s Sparrows stay together in pairs during the nesting season, but in the winter they will join with small flocks of other sparrows. Brewer’s Sparrow is a short-distance migrant, and like most other songbirds it migrates at night.
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Description of the Brewer’s Sparrow
The Brewer’s Sparrow is very nondescript, with a grayish head, faint streaking on the crown and nape, a white eye ring, plain, buffy-gray underparts, and indistinct wing bars. Length: 5 in. Wingspan: 7 in.
Same as male.
Seasonal change in appearance
Fall and winter birds are slightly buffier below.
Juveniles have streaked underparts.
Brewer’s Sparrows inhabit sagebrush, weedy fields, and pinyon-juniper woodlands.
Brewer’s Sparrows eat insects and seeds.
Brewer’s Sparrows forage on the ground or low in vegetation.
Brewer’s Sparrows breed across much of the western U.S. and southwestern Canada. They winter in the southwestern U.S. and Mexico. The population has declined in recent decades.
Bent Life History
Visit the Bent Life History for extensive additional information on the Brewer’s Sparrow.
The Brewer’s Sparrow’s elaborate song makes up for its nondescript plumage.
A small, disjunct northern population is sometimes considered to be a separate species, the “Timberline” Sparrow.
The song consists of a highly variable series of trills and buzzes. A sharp “chip” call is also given.
The Clay-colored Sparrow has a gray nape and bolder head pattern.
The Baird’s Sparrow has more pronounced face markings with black spots on lower cheek.
The Brewer’s Sparrow’s nest is a cup of grasses, weeds, and twigs and is lined with finer materials. It is placed in a low shrub.
Color: Pale bluish-green in color with darker markings.
Incubation and fledging:
The young hatch at about 11-13 days, and fledge at about 8-9 days, though remaining dependent on the adults for some time.
Bent Life History of the Brewer’s Sparrow
SPIZELLA BREWERI Cassin
The following subspecies are discussed in this section: Spizella breweri breweri Cassin and S. b. taverneri Swarth and Brooks.Contributed by ROBERT T. PAINEHABITS
Nesting: In its typical haunts of exposed scrub vegetation, whether on the desert to the south or above the timberline in Canada, Brewer’s sparrow acts in a shy, retiring manner, and if its nest is approached it disappears readily into the brush. J. S. Appleton (1911), finding breweri to be a rather common resident of the Simi Valley, Ventura County, Calif., writes: “The birds are very shy, sneaking from the nest and running through the grass instead of flying; consequently the nests are rather difficult to locate. All the nests that I have found have been on a south slope, sparsely covered with sagebrush and cactus, with a thicker growth of smaller plants and shrubs between. The nests were in these smaller shrubs, generally not over a foot above the ground.” The nesting site is usually within the favored sagebrush habitat and almost always within four feet of the ground. I have found only one report of a nest actually on the ground, that by F. Kenagy (1914) for a normally constructed nest in a slight depression in an alfalfa field.
John G. Tyler (1910) records it breeding in vineyards near Clovis, Fresno County, Calif. All the nests there were much alike in placement and construction, being typically composed on the outside of dry grass stems and a few grass blades and roots, and lined with very small, dry brown rootlets and a few long horsehairs. The neat, compact structures impressed Tyler as being almost exact miniatures of nests of the California jay.
The nesting of taverneri has been described in some detail by H. S. Swarth (1930) in the Atlin region of northern British Columbia where, except for habitat, the details could apply to breweri as well. There, above timberline at 4,500 feet altitude, and in a dwarf fir-birch-willow habitat, Swarth was forced to work patiently to discover the nest. He writes:
A cautious return later resulted in flushing my bird at close range from a nest with four eggs. Even then, the bird arising not more than three feet away and directly in front, I had to make a careful search on hands and knees. The birch was only partly leaved out, but the closely interlaced branches made a perfect cover from above. The nest, its bottom a scant six inches from the ground, was loosely placed among the supporting vegetation, not fastened to the twigs. When the surrounding branches were cut away the nest was removed separately; it could not be kept associated with the shrubbery in which it had been placed.
The nest is constructed almost entirely of rather stiff dried grass stalks and gray shreds, apparently from the fire-weed. The lining is of fine dried grass and a few moose hairs. Average external diameter (excluding long, protruding stalks) 130 millimeters; inside diameter, about 50 mm.; inside depth, about 30 mm.
Eggs: Brewer’s sparrow lays from three to five eggs, with three or four being the usual number. They are ovate and slightly glossy. The ground of “bluish glaucous” or “Etain blue” is speckled, spotted, and blotched with such dark browns as “Brussels brown,” “mummy bro~rn,” “snuff brown,” or “cinnamon brown” with occasional undermarkings of “pale neutral gray.” They may be either very finely speckled, or marked with a few blotches and scrawls. In most cases these are sharp, well defined and concentrated toward the larger end. The eggs of the two subspecies, breweri and taverneri, are identical to one another and indistinguishable from those of Spizella pallida. The measurements of 59 eggs average 17.0 by 12.6 millimeters; the eggs showing the four extremes measure 18.8 by 13.2, 17.8 by 14.7, and 15i~ by 11.4 millimeters.
Plumage: D. K. Wetherbee (1957) described the downy tufts of natal plumage as “light drab to drab gray” in coloration. Jean Linsdale (1936b) in a study of heat exchange and color of nestlings recorded the color of the downy young as “dark, slate gray.” The juvenal plumages of both breweri and taverneri are described in detail by R. R. Graber (1955). According to him taverneri can be distinguished easily by the very heavy black streakings of the chest, upper belly, sides and flanks. In breweri these areas are only lightly streaked.
Brewer’s sparrow starts losing the streaked juvenal plumage in a postjuvenal molt soon after leaving the nest. H. S. Swarth (1930) notes in taverneri that “Young in streaked juvenal plumage were out of the nest by the middle of July, the postjuvenal molt was in progress the later part of July and early in August, and birds in first winter plumage, completely acquired, were collected by the middle of August. An adult in the midst of the annual molt was shot August 6, and others in fresh winter plumage throughout, on September 1 and 5.” There also is a partial prenuptial molt which, according to F. M. Chapman (1910), “appears to be confined to the head, where there is a slight feather-growth, and one April specimen has been examined which is acquiring new tertials, but the change to summer plumage is affected chiefly by wear and fading.
Ridgway (1901) states that the sexes are similar in coloration. He gives the color of the bill in life as pale lilaceous brown, darker at the tip and along the culinen. Sometimes the maxilla is blackish with a pale commissure, and the mandible lilac grayish. The legs appear to vary from pale brownish flesh to grayish horn color. Fuller and Bole (1930) describe the iris as hazel in both sexes, and the female as having a flesh-colored mandible and legs either “pale pinkish dusky flesh or pale horn color.”
Food: Stomach analyses, supported by a minimum of field observations, indicate that Brewer’s sparrow is a “beneficial” species subsisting on a varied diet of plant and animal foods. The most thorough study was conducted byE. R. Kalmbach (1914) in an effort to discover the agents of natural control of the alfalfa weevil Pivytonomus poticus, in which Brewer’s sparrow may be important. He examined the stomach contents of 46 Brewer’s sparrows during the summer months. In May weevils comprised 43.4 percent of the food and occurred in all but one of the 14 stomachs, averaging 2.2 adult and 6.9 larval weevils per bird. One bird which had not fed on the weevil was nine-tenths full of plant lice, a food item which occurred in 7 of the 14 stomachs and amounted to over 38 percent of the average diet. “Caterpillars were present in five stomachs, forming 7.7 percent. Spiders and miscellaneous beetles were estimated at about 3 percent each, and the remaining animal food was of small quantities under several heads. The vegetable portion (1.1 percent) was entirely weed seeds.” In June the sparrows’ diet was 64.6 percent weevils and 14.5 percent caterpillars, with again only a trace of plant material. In July weevils composed 44.8 percent of the birds’ diet, one individual having consumed 45 weevils’ larvae, but in this month plant material, mainly weed seeds, amounted t.o about 20 percent of the diet. These indications of a seasonal shift in dietary composition are borne out in a further analysis by Martin, Zim, and Nelson (1951): in the fall months 53 percent of the food was plant material, and in winter, 90 percent.
Kalmbach also examined the stomach content of three nestlings during June and found that their diet differed little from that of the adults. Other observers have seen only insects being fed to young birds at or near the nest. For instance, Grinnell, Dixon, and Linsdale (1930) noted an adult at Lassen Peak, Calif., carrying large insects to a recently fledged young bird. Isolated observations do not alter the pattern. A single specimen collected among Russian thistles at Flux, Utah, in September 1934, by G. F. Knowlton (1937b) contained 5 adult and 21 nymphal beet leafhoppers, 13 seeds, and numerous plant and insect fragments. Stomach analyses of three specimens obtained in summer in northern California (II. C. Bryant, 1911) disclosed that, despite insect abundance, these individuals had fed primarily on weed seeds augmented by a few small beetles.
J. Grinnell (1914b) notes that birds wintering in the Colorado Valley preferred to feed among the bushes on the desert and only visited the river for water.
Behavior: Although Brewer’s sparrow is the characteristic bird of sagebrush country, its drab coloration and generally shy manner do not attract much attention. Most observations, which all speak well of the sociability of this small sparrow, have been made on migratory flocks, to which attention is drawn by group size and vocalization. Brewer’s sparrows have been observed wintering in Texas in the company of white-crowned, black-throated, vesper, and Savannah sparrows (Van Tyne, 1936). A. C. Twomey (1942) records migrating flocks regularly of from 50 to 100 individuals in the Uinta Basin, Utah.
J. Grinnell (1923b), who considered breweri to be the most abundant sparrow in Death Valley, Calif., records his observations on a transient flock as follows: “These sparrows showed a great weakness for bathing.
They seemed to be spending most of the forenoon hours every day in the mesquites along the overflow ditches, thoroughly \vetting the plumage in the shallow streamlets and then perching in the green canopied branch-work above to preen at great length. Sometimes such bathing parties would be perfectly quiet save for the sound of fluttering wings. Then again some certain individual would break into prolonged singing * * “‘. Occasionally many, occupying adjacent mesquite thickets, would sing ecstatically in chorus, giving an effect of the bedlam of canary songs one hears in a bird store.”
Once on the breeding grounds, however, these sparrows become quite inconspicuous, ducking into hushes at the least provocation and keeping warily close to shelter when feeding on the ground. Flock activities cease, except for communal singing, and loosely defined territories are set up, with singing males occupying some regular vantage point, usually on the end of a branch in the vicinity oT the nest. Few data are available on territory size or the extent to which these may be defended. L. Wing (1949) indicates that there may be as many as 47 breeding pairs per 100 acres in eastern Washington.
The timberline sparrow behaves similarly. H. S. Swartli (1930) writes: “It was evident that singing males were occupiyng perches in fairly close proximity, a bird, perhaps, to every five or six acres, where conditions were favorable. They were wary, and generally flew before they could be closely approached, but always moved about within a rather short radius, unwilling to be driven far afield. For each singing male it seemed likely that there was a mate upon a nest near by * *
It does not seem to be known whether natal care is by the female alone or by both parents, and I find nothing in the literature on the behavior of a parent towards its offspring.
W. P. Taylor (1912) describes the flight pattern of breweri on its northern Nevada breeding grounds: “The birds made rather nervous movements, often flying irregularly into the air to a height of fifteen feet or more and then shooting straight down and coming to rest in a sagebrush. Certain variations in flight were observed. For instance, at times a manner of movement resembling that of a vesper sparrow was noted, the Brewer flying in a zigzag manner towards a bush at some distance and sinking to the ground behind it, repeating the operation on being flushed again.” The timberline sparrow acts in the same manner when flushed from the top of one of the balsam thickets on which it perches when suspicious of danger. II. S. Swarth (1926), impressed by the wariness of these sparrows, writes that when flushed they fly long distances and then dive into birch thickets. He found it difficult to dislodge and follow a bird from such a refuge, as they tended to run beneath the shrubbery and take flight from some distant point.
Both races of Brewer’s sparrow apparently behave similarly when an intruder approaches the nest. Many authors, among them J. 0. Tyler (1910) and Grinnell, Dixon, and Linsdale (1930), have commented on the apparent reluctance of an incubating breweri to leave its nest. Thus, approaches of less than 2 feet are sometimes possible if no rapid movements are made. These latter authors note that brooding birds driven from the nests fly off silently and sometimes return to a nearby bush “protesting weakly at the intrusion.” One bird returned quickly, and, hopping on the ground within 2 meters of the intruder, chirped excitedly. When disturbed, taverneri will occasionally remain near the intruder. 11. S. Swarth and A. Brooks (1925) observed pairs of excited birds “perched on the tallest bushes, jerking their tails in a manner seen in no other Spizella save moriticola.”
Voice: Brewer’s sparrow is said to be vociferous, especially on the breeding grounds, where it often engages in flock trilling. The greatest volume of song is attained in the twilight and da~m chorus, which on dark days will extend almost to noon, although individuals can be heard from time to time even during the night. W. P. Taylor (1912) writes that in Nevada during the latter part of May and the first of June breweri is a most vocal species, and can be heard earlier than 3:00 am. and later than 8 p.m. At this locality some singing continued until at least August 10, though it was certainly not so prominent at that date as earlier in the season.
The complicated phraseology of the song has made schematic representation difficult, and many authors have resorted to a verbal interpretation. F. A. Pitelka (1951) describes the song as weak, monotonous and not very noticeable, while Hartshorne (1956) states it “implies marked continuity and variety.” W. L. Dawson (1923) interprets the song as “weeeezzz, tubitubitubitubitub,” which indicates its repetitive nature but not the variations in pitch that may usually be heard.
To H. S. Swarth (1930) the song of taverneri suggests a cicada-like trill, with many interpolations suggestive of a canary’s song and, as with the canary, it was long-sustained. There seemed to be a fairly regular sequence of trills and stops, but it was not a short, definite and unvaried song, as with the golden-crowned and white-crowned sparrows. I. M. Cowan (1946), although not stating whether taverneri’e song is continuous or broken into phrases, gives its duration as 10 seconds.
At the close of the breeding season the song chorus stops, and the most common notes are an abbreviated song or twittering and slight note given as “tsip” (Rockwell and Wetmore, 1914). L. Griscom (1928b) notes that “the call note was a weak one for a sparrow,” and he describes it as about halfway between those of the Savannah and field sparrows.
Field marks: This species is a small, pale, grayish-brown sparrow of a very nondescript nature. The upper parts are brownish, streaked evenly with black on the back, hind neck, and scapulars. The top of the head is finely streaked, the side of the head unstreaked. The greater wing coverts are tipped with buffy white, which forms an indistinct wing bar. The tail is long and notched. The underparts of adults are unstreaked. The sexes are similar. The crown shows no hint of the rufous found in chipyAng sparrows. The adult claycolored sparrow is similar except for a light stripe through the center of its crown and a well-marked cheek pattern, both of which Brewer’s sparrow lacks. The juvenal plumage is similar to the adult but is less sharply streaked above, and the chest may be streaked with a dusky color.
H. T. Peterson (1961) points out it “resembles Chipping Sparrow but sandier, crown, finely streaked, no hint of rufous or median line. Young Chipping and Clay-colored Sparrows in fall or winter might be confused with it, but their crowns are usually browner with a pale median line.”
Enemies: Little is known about this aspect of Brewer’s sparrow’s biology, although undoubtedly individuals are exposed to about the same attacks by predatory animals as other small sparrows. Allan R. Phillips tells me that he collected a “red racer” with a still undigested Brewer’s sparrow in its stomach at Cofer Hot Springs, Mohave County, Ariz., about Sept. 23, 1948. Phillips had noticed two or three brewed in the top of a sparsely leaved, half dead bush, and then turned away for a few minutes. On his return he saw the snake stretched out among the upper branches about 1 or 1~ meters from the ground. Because he did not witness the capture, he was unable to state where the snake actually caught the bird.
H. Friedmann (1963) writes: “Brewer’s sparrow is a poorly known victim of the brown-headed cowbird. It has been recorded in this capacity only in Wyoming and New Mexico.”
Breeding Range: The timberline Brewer’s sparrow breeds in mountains of western Canada from southwestern Yukon (Kluane), north western and central British Columbia (Atlin region, Ilazelton), and central western Alberta (Jasper region) south to mountains of southeastern British Columbia (19 miles west of Invermere) and southwestern Alberta (Banif region).
Winter Range: The winter range is not known in detail; migrants have been taken south to Arizona (near Morenci), New Mexico (Escondido), and western Texas (Van Horn, Alpine).
Migration: The data deal with the species as a whole. Early dates of spring arrival are: Oklahoma: Kenton, March 20. Nebraska: Hastings, May 10. Saskatchewan: Eastend, May 3. New Mexico: Los Alamos, April 27. Arizona: Wupatki National Monument, March 20; Fort Apache, March 27. Colorado: Fort Morgan, April 16. Utah: Washington County, April 21. Wyoming: Albany County, April 22; Laramie, April 28 (average of 6 years, May 3). Idaho: Moscow, April 23. Montana: Missoula, May 7. California: San Diego, March 7. Nevada: Carson City, April 10. Oregon: Lava Beds National Monument, March 23; Klamath Basin, April 9. Washington: North Yakima, March 30. British Columbia: Kittitas County, April 10.
Late dates of spring departure are: Texas: El Paso, May 14. Arizona: Fort Mohave, May 28.
Early dates of fall arrival are: Arizona: Douglas and Sonoita, July 31. Oklahoma: Kenton, August 25. Texas: El Paso, September 11. Late dates of fall departure are: Oregon: Harney County, September 26. Nevada: Carson City, October 15. California: Hollywood, September 28. Montana: Fallon, September 12. Idaho: Lewiston, September 24 (median of 11 years, September 5). Wyoming: Laramie, October 21. (average of 5 years, September 25). Utah: Salina, September 5. Colorado: Weldona, September 30. New Mexico: Los Alamos, October 11.
Breeding Range: The southern Brewer’s sparrow breeds from central southern British Columbia (Whit.e Lake, Midway), northern Idaho (Moscow), southern Alberta (Deer Creek, Sweetgrass Hills), southwestern Saskatchewan (Eastend), central eastern Montana (Fort Keogh), southwestern North Dakota (Marmarth), western South Dakota (Belie Fourche, Black Hills area) and northwestern Nebraska south, east of the Cascades, through Washington and Oregon, to eastern California (south to San Jacinto Mountains), central Arizona (Fort Whipple, Camp Verde), northwestern New Mexico (Fort Wingate, Santa Fe), and central southern Colorado (Fort Garland).
Winter Range: Winters from southern California (San Fernando Valley, Providence Mountains), southern Nevada (Nelson), western and central Arizona (Hualpai Mountains, Safford), southern New Mexico, and western and central Texas (El Paso, Guadalupe Mountains, Boerne) south to southern Baja California (San Jos6 del Cabo), Jalisco (Juanacathln), Guanajuato (Irapuato), and southern Texas (Brownsville); casually north to northern California (Glenn County). In migration through western Kansas and western Oklahoma.
Casual records: Casual (this race?) in Louisiana (Cameron).
Accidental in Massachusetts (Watertown).
Egg dates: California: 84 records, April 19 to July 16; 9 records, May 13 to June 3; 34 records, June 7 to June 17. Colorado: 5 records, May 24 to July 21. Montana: 3 records, May 29 to June 16. Nevada: 6 records, May 28 to June 22. New Mexico: May 20 to July 10 (number of records not stated). Oregon: 36 records, May 18 to July 22; 19 records, May 24 to June 16. Texas: 6 records, May 21 to June 12. Utah: 20 records, May 6 to July 18; 10 records, May 29 to June 7. Wyoming: 13 records, June 1 to June 25.