Although the Brown-capped Rosy-Finch occurs farther south than its two closely related species, it breeds at a higher altitude than any other U.S. or Canadian species. Brown-capped Rosy-Finches forage for seeds and frozen insects from the surface of snow, managing to survive in what appears to be an extremely inhospitable environment.
The breeding biology of the Brown-capped Rosy-Finch is unusual in that the male defends his mate wherever she goes, rather than defending a particular territory. It is thought that this is the result of having fewer females than males in the population.
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Description of the Brown-capped Rosy-Finch
The Brown-capped Rosy-Finch is a small, hardy finch with brown upperparts and breast and a thick, pointed, seed-eating bill. Reddish wings, rump, and belly. Grayish-brown cap.
Seasonal change in appearance
Similar to adult females.
Alpine snowfields and rocky alpine areas.
Seeds and insects.
Forages on the ground or on the snow.
Resident in parts of the Rocky Mountains.
Both intruding males and females may be chased by members of a breeding pair.
Brown-capped Rosy-Finches usually remove the hulls from seeds, but will swallow especially hard seeds whole.
A variety of chirps, peents, and chews are given.
Other rosy-finches have pale gray napes.
The nest is a cup of moss and other plant materials placed in a crevice or hole.
Incubation and fledging:
– Young hatch at 12-14 days.
– Young fledge (leave the nest) at 18 days but remain with the adults for some time.
Bent Life History of the Brown-capped Rosy-Finch
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 Brown-capped Rosy-Finch – the common name and sub-species reflect the nomenclature in use at the time the description was written.
LEUCOSTICTE AUSTRALIS Ridgeway
Contributed by FRED MALLERY PACKARD
The high rugged mountains of Colorado are the home of the browncapped rosy finch, a species with close affinities for the arctic environment of that region. Its range is almost entirely restricted to the western half of Colorado, although it has been found in northern New Mexico near the Colorado boundary. Nesting on peaks, usually above 12,000 feet, it migrates altitudinally to the lower hills for the winter. It rarely descends below 6,000 feet, and it has not been recorded below 5,000 feet.
Within its limited range the brown-capped rosy finch is a common bird, especially numerous on the lofty meadows of the Front Range and Arapahoe Peaks that form the eastern chain of the Rocky Mountains. An ascent of almost any suitable peak in Colorado in summer should result in the discovery of one or more groups of these finches flying up from the tundra, feeding on the lingering snowbanks, or perched on a nearby outcrop. They, with the white-tailed ptarmigan, are truly birds of the summits; of the species that nest above timberline the ptarmigan remains closer to its summer home throughout the year.
Courtship: Although brown-capped rosy finches are plentiful and locally abundant throughout their range, few trained observers have recorded their behavior prior to the nesting season. Because much of their high alpine habitat is nearly or completely inaccessible to man until very late spring, little information about their territorial and courtship habits is available.
Lack (1940) writes that they arrive on the arctic tundra in sizable flocks, already paired. F. W. Miller (MS.) notes that “as mating takes place, the flocking is still adhered to, even with eggs or young in the nest, they always appear in company. But the flocks are less unified, and the pairs and individuals act independently.” Robert J. Niedrach, Assistant Director of the Denver Museum of Natural History, who has studied the bird life of Colorado for more than 50 years, told me that during the mating period, from the last 2 weeks of June to early July, the male performs a conspicuous song flight. Undulating in a large circle that covers 10 to 20 acres, he sings on the wing steadily for 5 or 10 minutes before finally descending to the ground to feed. The male sings actively during the early part of nesting, but less so when incubation begins. Thereafter, only an occasional song in flight is heard, and the characteristic call that birds of both sexes give on the wing as they fly directly between the feeding and nesting grounds. He found flocks of 10 to 15 individuals together just before the nesting season, but during the nesting period the birds were observed singly or in pairs. Where several nests are in fairly close proximity, as on a single side of a peak, a number of individuals may be seen at one time in a limited area. At Rocky Mountain National Park I noticed that rosy finches did not occur in flocks during the nesting season.
Nesting: The brown-capped rosy finch nests at elevations above 12,000 feet throughout the western half of Colorado and extreme northern New Mexico wherever alpine tundra, precipitous cliffs, talus slides, and slow-melting snowbanks combine to form the requisite ecological conditions. The species probably nests also along the Colorado border in Utah and Wyoming where a similar habitat exists, but evidence of this is lacking.
Despite the species’ abundance in many parts of its range, very few nests have been studied or collected. F. C. Lincoln (1916), reporting the discovery of the first known nest by H. R. Durand, A. H. Burns, and himself, writes:
The nest was discovered July 11, 1915, on the southwest exposure of the south peak of Mt. Bross, Park County, Cob., at an elevation of 13,500 feet, or within 600 feet of the summit, the elevation of Mt. Bross being 14,000 feet. This altitude of the nest site here marks the limit of plant growth, the remaining 600 feet being bare rock, either slides or in the form of outcropping or small cliffs.
It was in one of these latter that the nest was found * * * The face of this cliff had suffered considerably from erosion, resulting in “chimneys” and cavities from a few inches to several feet in diameter, and in one of the smaller of these the nest was placed. The hole, forming the upper terminus of a vertical crack, ran hack twelve or fourteen inches and was about forty inches [sic] from the base of the cliff.
A number of nests from Mt. Bross were studied and added to the collection of W. C. Bradbury. About these nests, F. W. Miller in 1921 writes: “On Mount Bross, the rosy finch is abundant everywhere above timberline, though it nests exclusively on the southwestern or Buckskin side at an altitude of 12,000 feet up. This locality is ideal, the entire side of the mountain being one huge rock slide, varied and broken with cliffs and outcrops * * “‘. All the nests were found in cliffs; one was placed on a shelf of rock in a prospect tunnel. The usual site is in a hole or crevice in the face of a sheer rock cliff. Where the rock is in lime formation, the nest is occasionally placed several feet back in a narrow fissure. No nests or signs of nests were found in the rock slides.”
The nest may be placed in a blowhole or shallow crevice only a few inches within the cliff face, or it may be far back in a larger crack beyond arm’s reach. Less frequently it is built behind or under a large rock amid finer detritus. One nest was discovered in a depression on the surface of a cliff protected by a large overhang of the escarpment. The nests always appear to be from 6 to 40 feet above the top of the talus slide at the base of the cliff. These sites provide shelter from the frequent blustery winds, rain squalls, lightning storms, and occasional snows that strike the alpine meadows during summer.
All the nests so far discovered appear to have been hidden in perpetual shadow, entirely out of reach of the sun’s rays. Niedrach photographed parent birds feeding young in a nest on a shelf of rock 15 feet back in a cavelike opening that was so dark he could not cast light on the nest itself even with the aid of mirrors. Such sites must be very cold, especially at night. One nest on Mount Bross was frozen tightly to ice formed by the congealing of water trickling down during the frigid hours of darkness.
The nest consists of a cup of fine material tightly woven into an outer matrix of alpine moss (SpluLgnum). Lincoln (1916) describes it thus: “The bulk of the nest was of dry grass and flower stems neatly and compactly woven together with a considerable quantity of fine moss, and lined with a fine yellow grass and a few feathers from the bird’s body, with one White-tailed Ptarmigan feather. It rested well into the silt which covered the bottom of the hole, and the cup was placed to one side, thus giving walls of unequal thickness on two sides. This inequality did not, however, change the general exterior shape, which is practically round *
A nest collected by A. T. Wheeler, now in the University of Colorado Museum, is practically circular, both exteriorly and interiorly, but the sides of the cup flare outward below the rim so that the cavity is wider inside than at the top. Lincoln’s nest was 4.75 inches in diameter, with an overall depth of 3.00 inches; the cup was 2.50 inches in diameter and 1.60 inches deep. A nest in the University of Colorado Museum measures 5.69 inches in diameter and 2.81 inches in overall depth; the rim of the cup is 2.37 inches in diameter; the widest interior diameter is 2.75 inches; and the depth is 1.62 inches. A third nest, in the Chicago Natural History Museum, of which only the cup has been preserved, has the following dimensions: inner diameter of rim, 2.60 inches; greatest inside diameter, 2.75 inches; inside depth, 1.5 inches; overall depth, 2.50 inches.
The outside of the nest appears always to be solely of alpine moss. The cup is firmly woven into this matrix, the bowl composed of very fine grasses, flower stems, and rootlets, the rim of slightly coarser grass stems, and the underside of the cup, hidden by the moss, of still coarser bits of stem an inch or less in length, all closely woven together. The cup sometimes includes traces of a variety of other materials: ptarmigan and rosy finch feathers, rabbit and cony fur, elk and burro hair, pieces of cloth, ravelings of burlap, and, in one nest, a section of blasting fuse. One egg was found with cotton adhering to the shell. Occasionally small sharp pebbles fall into the nest and dent the fragile egg shells.
Nest building begins about June 20 or later, and the actual construction of the nest does not take long. F. W. Miller (MS.) watched a site that was vacant on July 12; on July 14 the nest was complete except for the lining; by July 16 it had been finished and two eggs laid. Three days later the set of five was complete and the female was incubating. Niedrach told me that in his experience the female builds the nest alone; he never saw a male bring material to it.
Eggs: The number of eggs in complete sets varies from three to five. Several nests Niedrach studied in the Arapahoe Range contained the smaller number, while of 13 nests F. W. Miller and others watehed on Mount Bross, 1 contained two eggs; 2, three eggs; 5, four eggs; and 5, five eggs.
F. C. Lincoln (1916) describes the eggs as “pure white, slightly glossy, unmarked; ovate pyriform in shape; measurements in inches:: .91 X .60; .95 X 63; .97 X 62.” Other sets examined by the writer agree with this description, with slight variations in the measurements.
The measurements of 50 eggs average 22.7 by 15.6 millimeters; the eggs showing the four extremes measure 25.8 by 16.0; 25.1 by 16.5; 20.5 by 16.0; and 23.2 by 14.8 millimeters.
In his notes, F. W. Miller mentions indications of pigmentation on one set of eggs be collected; but when they were blown for preservation, no trace of pigment could be seen. The shells are very thin and fragile, and of the few sets that have been collected, a number have been broken in the blowing or otherwise destroyed.
According to the limited data available, eggs are laid at the rate of one a day until the cluteh is complete. The earliest date eggs have been found is June 30, when a set of four was discovered on Mount Bross. Fresh eggs have been found as late as July 19, which were the second set of five laid in a nest from which the first set had been collected on July 8. A nest completed on Arapahoe Peak, Grand County, on July 28, contained three eggs on August 7, the date the eggs were taken.
Young: According to Niedrach, incubation probably lasts from 12 to 14 days. The earliest hatching date noted is July 8; full clutehes of eggs still under incubation have been found several times as late as July 27. Incubation of second sets, when laid, probably continues into early August. No exact temperatures of the air around the nesting sites have been taken, but the sunless crevices and caves are extremely chilly, even though protected from direct winds. Trickles of water running down the surface of the rocks near the nests frequently freeze at night. The young remain in the nest about 18 days and are fed by both parents, often at the same time. The parent not on the nest at night roosts in a crevice nearby. The adults show little fear of man at this time. They frequently flew within 6 feet of Niedrach while he was taking motion pictures of them feeding their young. When the nestlings are half grown, they emit a continuous loud chirping which carries a long distance and helps locate the nest sites. The fledged young are fed on the ground until they are able to forage for themselves, and remain with the parents during August and at the least, into September, forming family groups on the alpine tundra.
Plumages: The brown-capped rosy finch differs from all other leucostictes in lacking distinct or clear gray markings on the head. Ridgway (1901) writes: ***** there is a quite well defined area covering exactly the same parts of the pileum as in L. tephrocotis tephrocotis and L. atrata, that is differently colored from the contiguous parts, but instead of this area being clear and perfectly uniform light ash gray the feathers are dusky brownish gray centrally, margined with light brownish gray, producing a more or less squamate or scale-like appearance; furthermore, the brown color which borders this somewhat grayish area is decidedly lighter and duller, or less rufescent than in L. tephrocotis.”
Of the several leucostictes, only L. atrata and L. australia show striking sexual color variation, and in L. austraiis there are also marked differences between the summer and winter plumages of each sex. Ridgway (1901) describes the adult male in summer as follows:
Pileum dusky grayish brown, becoming nearly or quite black on forehead; nasal tufts whitish; rest of head, together with neck, chest, and breast, deep cinnamon-brown or dull russet, deepest on throat, where often, as on chest and breast also, tinged or flecked with bright red; hindneck, back and scapulars similar, but duller * * ~, with narrow, more or less indistinct, shaft-streaks of dusky; feathers of rump and upper tail-coverts broadly and abruptly tipped with peach-blossom pink; the remaining portion of the feathers grayish brown * * sides, flanks, and abdomen mostly carmine-pink * * *; under tail-coverts deep grayish brown or dusky centrally, broadly and abruptly margined with pink and white; wings dusky, with lesser and middle coverts broadly tipped with peach-blossom pink, the greater and primary coverts and remiges edged with the same: the color very bright, almost scarlet, on the wing-coverts in some midsummer specimens; tail dusky, edged with pale brownish gray and pinkish; bill and feet black.
In his monograph on the genus Leucosticte (1875), he adds: “In the male, the red of the lower parts extends much farther forward than in the other forms, always covering pretty uniformly the entire abdomen and sides, while it sometimes invades the breast, or even sometimes the throat and cheeks.” In the adult female in summer, he says, the prevailing color is “pale grayish-brown-umber, the pileum hardly appreciably different, and the forehead scarcely inclining to black; red markings almost obsolete, and distinctly indicated only on the lesser wing coverts and rump; greater coverts, remiges, and rectrices skirted with whitish; abdomen scarcely tinged with red *
“In midsummer [June and July], the pale margins of the crown and grayish brown of the plumage wear off, so it becomes more uniform, while the red of the male is heightened into an intense crimson, or harsh carmine tint.”
A. W. Anthony (1887) describes the adult male in winter (January) thus:
Pileum grayish black, darkest anteriorly, slightly paling to grayish on occiput; lores dull blackish; nasal plumes white. General color above and below light umber-brown, tending to chocolate on the chin and throat. Feathers of the back with darker shaft-lines and paler edges; those of the breast but slightly tipped with whitish. Hinder parts of the body, above and below, rich carminered; primaries, outer four secondaries, second, third, fourth and fifth rectrices edged, and lesser wing-coverts broadly tipped with same color. Wings and tail blackish, all of the primaries and secondaries broadly, and median pair of rectrices slightly, edged with dull white. Lining of wings white, edged with rosy.
The female in winter is similar to the male in general color, but paler, and varies considerably. The rosy hues are usually very faint and may be almost entirely absent.
The immature male closely resembles the adult, the principal difference being that the greater wing coverts are edged with whitish in summer and with huffy in winter.
The juvenal plumage is generally grayish-brown, the crown being dull grayish-black with gray edges on the feathers, the sides of the head and neck grayish-brown darkening on the chin and throat. The lower parts are light brown anteriorly, each feather edged with whitish, the abdominal feathers light dusky, with pinkish and whitish edges. The back is dull brown, the upper tail coverts and lesser wing coverts with rosy markings, the wings and tail blackish.
In winter the bill is yellow, tipped with black. In early March the yellow becomes clouded with dusky horn color, and it darkens progressively through April and May until by June it is intense black. The feet are black at all times.
Field marks: Rosy finches are rather chunky, sparrowlike ground birds that look darker than the other ground finches of the region. The brown-capped rosy finch lacks the distinct gray area on the crown common to the other leucostictes, and the general coloration is lighter brown and duller. The rosy feathers of the adult male are bright, especially in midsummer, and often extend forward to the breast or throat. Females are duller and paler than males, are less rosy, and sometimes show no pink at all. Their blended colors, lacking in contrast, help identify them. Young birds lack rosy feathers and are nondescript.
A. W. Anthony (1887) writes: “In comparing the full plumaged australis with L. tephrocotis, both in winter dress, I find the latter much the darker bird, the umber-brown on the breast and back of the female tephrocotis being of about the same shade as that found on the male australis. In tephrocotis the rosy hue is less extended, decidedly duller, and more broken by the ground colors of the body. In tephrocotis I often find the rump marked with crescent-shaped rosy spots on a chocolate ground, while in australis, although the rosy patch is seldom, if ever, continuous, it is usually less broken and extends farther forward.”
Food: The brown-capped rosy finch feeds principally or entirely on insects, seeds, end small plant fruits that occur on or near the ground. So far as has been recorded, it seldom, if ever, feeds in the air. In high altitudes grasses and flowering plants grow only a few inches tall and their growing season is brief. They come rapidly into seed and are quickly replaced by a new succession of plants. Thus a constantly renewed abundance of seeds and fruits is available to the rosy finches.
E. R. Warren (1916) collected two females that were foraging for their young at 11,500 feet in Elk Basin, Gunnison County, on June 28. Analysis of their stomach contents showed that in one, 80 percent was seeds of Alsirte (media?) or chickweed, with shelled seeds of Bidens, seeds of Eragrostis, Polygomum, Corizus hyalinus, Corizus indentatus, and Balciutlut impicta, one Trypeta, and traces of beetles and spiders. The other contained 50 percent Bidens seeds, 35 percent Alsine, 10 percent Eragrostis, and some Corizus, a fly, and traces of beetle. On Specimen Mountain in Rocky Mountain National Park I once watched a rosy finch fluttering over a growth of arctic willow (Salix sp.) but could not determine whether the bird was feeding on buds or on insects.
Rosy finches are frequently seen hopping about on the patches of snow that linger on the alpine meadows until late summer, sometimes until new snow falls in autumn. It is often assumed that the birds do so to eat the snow as a source of water, but at least for the browncapped rosy finch, there is no valid evidence that they do so. Niedrach, who has carefully watched the activities of these birds on snowbanks, informed me that he has never seen any rosy finches actually eating snow, and that the birds are apparently seeking seeds that have blown there sometime previously. These seeds form strata or lenses in the snow that are readily visible to the eye, and become impregnated with snow water until they are very soft. As the snow melts, they appear on the surface of the patch, where the rosy finches gorge themselves on them. F. W. Miller (MS.) notes that these snowbanks are the favorite feeding grounds of the rosy finches as long as the patches remain, lie observed that the birds feed extensively on dead and torpid insects that have been chilled and dropped to the ground. He says that “As the season advances and the snow disappears, the birds resort to the cliffs and rock slides, where they find a variety of insect food, including a large number of moths. After a storm, they are always out to gather up the insects that have taken refuge in the grass and litter.”
The winter diet is almost completely herbaceous, except for such animal substances as may be present in refuse heaps visited by the birds. Roadside grass and weed seeds supply a large proportion of their nourishment at this season, especially the Russian thistle or tumbleweed (Salsola sp.), which they eat until their crops are overfull (Warren, 1910). Aiken (Ridgway, 1875) reports them to be very fond of hemp and canary seed, from which they remove the shells almost instantly.
Behavior: Leucostictes are more at home on the ground than above it, but they do alight occasionally on bushes, trees, fences, or buildings. E. R. Warren (1915) watched a flock of brown-capped rosy finches at timberline on Mount Bross in late September and writes: “Several of them worked down a little and perched in some dead trees, in the topmost branches, something I do not recall having seen these birds do before, though when at lower elevations in winter I have seen them in low bushes or trees.” During the winter when mixed flocks of rosy finches forage along the roadsides of the mountain “parks,” passing vehicles often flush them from the weeds. Usually they alight on the ground a hundred yards or so away, but not infrequently some will perch briefly upon a fence wire or tall weed, seldom staying there more than a few seconds.
On their alpine meadows in summer, the rosy finches are shy and quick to fly at the approach of an intruder. By sitting quietly, however, one may watch them at fairly close range, especially if one settles near a favored snowbank where the birds come to feed. The parents of a nest of young Niedrach (MS.) was photographing showed no fear at his presence. In winter they become tame and confiding. Robert Ridgway (1875) quotes C. E. Aiken, who studied these birds at Colorado Springs during that season: “Every morning they came, usually only one or two at a time, to pick up crumbs in the door-yard, and fearlessly ventured on the porch for seeds that fell from a canary cage hung there; indeed, so tame were they that they would pick seeds at my very feet as I dropped them from my hand. During two days that I remained in town I caught five alive under a common flour-sieve * * .” In Rocky Mountain National Park I have often walked to within 10 feet of winter flocks of leucostictes, and once a band settled to the ground all around me.
Their habit of carrying their bodies close to the ground gives a flock of feeding rosy finches some resemblance to longspurs, but they do not creep as longspurs do. Aiken writes (Ridgway, 1875): “They move on the ground with quick, short hops, their feet so closely drawn up into their ruffled feathers as to be almost invisible.”
Enemies: Probably rosy finches fall prey occasionally to the several species of hawks and other predators present on both their summer and winter ranges, but the only reported attack on brown-capped rosy finches appears to be that of Niedrach (MS.), who watched a merlin (Falco columbarius nc fulrdsoni) chase some of them unsuccessfully at a roost at Morrison.
Voice: The note most frequently heard from the brown-capped rosy finch is a rather harsh, goldflncblike peyt-a-weet the birds utter as they rise from the ground and repeat on the wing. The incessant prenuptial singing of the male has been described above, as has the continual chirping of the nestlings and the characteristic call the parents use when flying between the nest and feeding ground. After the young fledge, the adults are rather silent, occasionally emitting a thick-toned chirp, but the young birds keep up an incessant clamor, “like young chimney swifts,” as F. M. Drew (1881) describes it. “The wind was very high at the time [August 17], and often while standing in a lode drift, the noise would go rushing by sounding like the distant jingle of sleigh bells.”
In winter the foraging flocks are conversational, twittering together quite noisily, and the birds are very quarrelsome and noisy about their roosts. Aiken (Ridgway, 1875) describes a winter song: “I have several times heard one of them sing, a pretty, warbling song, somewhat like that of the canary, but so low as hardly to be heard at a distance of more than two or three rods.” I have heard what were probably fragments of this song among the winter flocks at Rocky Mountain National Park.
Winter: The foothills of the Front Range and of the Arapahoe Range rise abruptly from the Great Plains about 20 miles west of Denver. The first isolated ridge, known as the Ilogback with an average elevation of 5,500 feet, marks the normal eastern limit of the winter range of the brown-capped rosy finch. Westward the species is found in winter in most of the basins and mountain “parks” that lie between the ranges, particularly in North Park, Middle Park, and South Park, southwestward to Mesa Verde National Park, and at a number of other places in the western half of the State. Some of these leucostictes occur in winter in immediately adjacent parts of New Mexico, casually in Wyoming, and possibly in Utah.
The descent to the lower ranges begins in late September and becomes pronounced when the first severe autumn snows strike the peaks. Through October and November, as the storms increase in severity and frequency, flocks of from 50 to more than 100 rosy finches begin to appear in the foothills. At Rocky Mountain National Park small bands composed entirely of australis arrived in the Transition Zone at 8,500 feet in mid-October; usually they do not remain then, but move higher again after the snow that prompted their first descent has melted. The November storms, however, produce permanent snows on the alpine meadows, and thereafter many of the birds either stay in the Transition Zone “parks,” or descend into the foothills. Even at that season small flocks may be found above timberline, and a number return to the summits in winter whenever the weather clears after storms.
Niedrach found the species common during the entire winter of 1918 at 13,000 feet on Quartz Creek, at the edge of Taylor Peak, Pitkin County. The birds appeared in bands of three or four to a dozen, searched the newly turned soil of excavations for food, and ate refuse the cook threw out. Horace G. Smith, of Denver, told me that these finches were often present in large flocks in winter near mines high in the mountains, where they frequented the places where the cooks disposed of dishwater containing crumbs and other food.
In late October three other species of leucosticte arrive in Colorado from their summer ranges and join the brown-capped rosy finches to form mixed flocks which may number a thousand birds, though groups of one or two hundred are more usual. The gray-crowned rosy finch (L. t. tephrocotis) soon becomes the most common form, almost equaled by au~stralis. Hepburn’s rosy finch (L. t. littorali.s) is fairly numerous, often making up a quarter of the total, while the black rosy finch (L. atrata) is always rather rare, seldom represented by more than one or two individuals. These flocks consist entirely of leucostictes; no other birds mingle with them in the meadows. Sometimes a small flock is comprised entirely of australis, but this is not always the rule.
Every mountain storm drives the birds to lower elevations. Severe blizzards bring thousands to the foothills, where they remain as long as the inclement weather lasts. When the weather clears, many follow the receding snowline back into the higher country; others remain for some weeks in the valleys, while still others make a daily trek in clement periods to elevations 2,000 to 3,000 feet above their roosting sites. If the fair weather is prolonged, a number return to the alpine tundra until the next storm drives them down again. Aiken writes (Ridgway, 1875): “A storm gathers them into a dense flock, when their habits are much like those of the Shore-Larks EOtocoris]; but, on the return of pleasant weather, the flocks are dispersed, and the birds are found singly or in small companies.”
At night during the winter the rosy finches congregate in roosts, all four species together, sometimes numbering a thousand or more. Niedrach (MS.) has studied such a roost at Red Rocks Park, at Morrison, Cob., a 6,000 feet elevation. The birds begin to arrive there from the hills above about 3:00 p.m. and do considerable foraging before seeldng their sleeping crannies. They quarrel vociferously among themselves over the roosting spots, flying in and out of the cliffs until it is totally dark. In this roost each bird occupies a little bbowhole, which is usually soiled with a great mass of droppings. In another roost, along the Hogback west of Denver, the birds sleep in cliff swallow casings in association with juncos, house sparrows, and pine siskins.
These foothill roosts are occupied nightly until about April 10, and are then abandoned, the birds presumably moving up a few thousand feet with the retreating snows. Through April and early May many birds remain at elevations of 7,000 to 9,000 feet, the migrant species disappearing from the region gradually. A late spring storm may force the remaining birds down into the foothills briefly, but as these snows melt quickly, they soon return. As the alpine tundra blows clear of snow and the brown-capped rosy finches ascend to their nesting ranges, the wintering flocks gradually diminish.
Horace G. Smith of Denver reports that he has seen browncapped rosy finches on two occasions in that city, both times in winter. One flew into an open window of a residence, and a band of the birds once entered a cowshed to roost for the night.
Range: Wyoming, Colorado, and New Mexico.
Breeding range: Breeds in the mountains of southeastern Wyoming (Medicine Bow Range), Colorado (near Walden, Pikes Peak) and central northern New Mexico (Wheeler Peak).
Winter range: Winters at lower altitudes within the breeding range. Migration: Late dates of spring departure are: Colorado: Colorado Springs, May 28; Walden, May 21 (median of 8 years, April 10).
Early dates of fall arrival are: Colorado: Walden, November 4 (median of 7 years, November 13).
Egg dates: Coborado: 11 records, June 28 to July 27.