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Bent Life History of the Black-headed Grosbeak

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 Black-headed Grosbeak - the common name and sub-species reflect the nomenclature in use at the time the description was written.

 

BLACK-HEADED GROSBEAK
PHEUCTICUS MELANOCEPHALUS MACULATUS (Audubon)


HABITS


From the eastern foothills of the Rocky Mountains to the Pacific coast the handsome black-headed grosbeak replaces our familiar rose-breasted grosbeak of the eastern States. It is not quite as showy as the eastern bird, but it is richly colored, the brownish orange of the under parts contrasting well with the black head and the black and white of the wings and tail. The western race, the subject of this sketch, breeds from southern British Columbia through California to northern Lower California and western Mexico.

One should look for the black-headed grosbeak in situations similar to those in which one could expect to find the eastern rosebreasted gr~sbeak, in thickets of bushes, small trees or willows which grow along streams, around the edges of swamps, ponds, or damp places, as well as on the edges of open woods, where the sunlight filters down through the foliage, but almost always not far from water or low ground. S. F. Rathbun says in his notes: "On more than one occasion, when in a forest where no sign of any break was seen, we perhaps ~vould hear from far away the clear song of this grosbeak; and then we' knew that in the direction whence it came would be found some more or less open spot, possibly bordered by a bit of water or a stream. And other somewhat favored spots are about the borders of the forest that have a mixture of deciduous growth."

Henry G. Weston, Jr. (1947), writes of its haunts in California:

Grosbeaks may ordinarily be found in the woodland or in riparian groves and thickets: in these two major types of plant cover, the trees and marginal or understory bushes are used for almost all routine activities. In general grosbeaks are most often found in the open woods. The extensive peripheral foliage characteristic of open woods is advantageous in foraging for food; for singing perches, grosbeaks appear to require fsir visibility, and this feature is again best afforded by open woods. Nesting occurs most commonly in streamside bushes and trees and in the live oaks of open woods. Along edges or transitions between grassland and woodland or chaparral, grosbeaks are also common; but they enter chaparral and grassland only infrequently and then only in search of food.

Mrs. Irene G. Wheelock (1912) adds: "Among the alders that border small streams in the valley, in the cherry orchards at cherry time, in the potato field when bugs are rife, in the oaks and evergreens of the lower Sierra Nevada, one may hear the metallic 'eek, eek,' of the Black-headed Grosbeak."

Spring: According to Weston's (1947) records, the occurrence of this grosbeak in the San Francisco Bay region "is limited normally to the months between April and September, inclusive. * * * The earliest recorded date is April 4, the latest, April 21." The males arrive about six days before the females. They "arrive singly rather than in flocks and are solitary for the few days preceding arrival of females. They begin singing upon arrival, and their activities before the females appear consist largely of foraging in the live oaks and willows and uttering frequent songs from exposed perches. Males appear to be spaced, but I saw no conflicts between them until after the arrival of females."

In the vicinity of Seattle, according to Rathbun (MS.), "one may look for the arrival of this species some time during the earlier part of May. A single bird only may be seen or perhaps several in company loosely associated. By the latter part of May they are mated and the pairs well established in the localities selected for a summer home. And each pair seems to have a defined territory, for we have never found a pair nesting anywhere near another; and should the locality not be subject to much change, the birds form an attachment for it, continuing to frequent it from year to year."

Weston (1947) noticed a number of conflicts between mated pairs in defense of their respective territories, in which the females were more aggressive than the males; the females "repeatedly postured and flew at each other, and at each attack, loud songs, calls and sounds of bodily contact could be heard."

Courtship: The same observer writes: "The only type of display seen was a nuptial flight. Loud songs were uttered from some exposed perch near a female and then the male would suddenly fly up and out, performing a song-flight in the air above her. Flying forth on a horizontal cointe, the male would circle out from the summit of a tree, with wings and tail spread, uttering an almost continuous song. In the air for eight to ten seconds, he would then fly back, usually to the perch just vacated. I have never seen this display before a female coming more often than four minutes apart. Song-flights are not restricted to the courtship period but also occur, although less frequently, while the female is incubating."

Nesting: yIn his study of the breeding behavior of the black-headed grosbeak, Weston (1947) writes:

Nesting usually takes place in deciduous bushes and trees bordering streams. Nests are built also in bushes or trees away from stream courses in gardens, dense brushland, closed woods and parkiands; but these occurrences form a small percent~ge of the total when compared with nestings near streams. Records of one hundred and twenty nests, from literature and specimens, show nests placed in twenty-nine different species of plants. Close to eighty per cent of the plants used were deciduous: willows were represented most frequently and constituted thirty-five per cent of the total. Second in species representation, however, is the evergreen coast live oak (Quercus egrifolia), with twelve per cent of the total. Nevertheless, species of next ranking frequency are all deciduous; these are, in order, alder (A laus rhombifolia), big-leaf maple (Acer macro phyllum), blackberry (Rubus vitifolius), cottonwood (Pa pulus), and elderberry (So mbucus glance).

Nests are placed in trees and bushes, usually at a height of six to twelve feet above the ground. Among height records of 163 nests from various localities in California, I found the average to be ten feet above ground. Seventy-eight, or 66 per cent, of these nests were placed between four and twelve feet above ground. The support for the nest usually consists of a crotch or fork in a group of horizontal or vertical secondary branches. * *

The nest is a bulky, loosely constructed affair, ordinarily composed of slender twigs, plant stems and rootlets, in the base and outer walls, and of finer stems and rootlets lb the lining. * *

Building of the nest is done by the female. Suitable nesting material is normally sought within one or two hundred feet of the nest site and occasionally as far as 350 feet. The male usually follows her while she is gathering nesting material and he may accompany her to the general vicinity of the nest; however, I have never seen a male carry nesting material nor in any way aid in the actual construction of the nest. * *

Construction of the nest takes from three to four days. Most of the building occurs in the mornings. Visits to the nest become less frequent and more irregular, as the day progresses, and in the afternoon the nest is visited occasionally without any nesting material.

W. Leon Dawson (1923) says: "The nest of the Black-headed Grosbeak is of singularly light and open construction, evidencing, as we suppose, the habit of the tropics, where ventilation, rather than conservation of heat, is the object sought. Some nests are so thin that the eggs may be counted from below." He mentions a nest that was kept cool by evaporation: "Instead of the usual lace-work construction," the birds "heaped up a mass of green willow leaves, plucking for the purpose the terminal twigs of the youngest trees, and wedging them to a height of nine inches in a convenient crotch. In the top of this mass, kept cool by reason ol evaporating moisture, they set the conventional root: line cup.~~ J. Stuart Rowley writes to me: "I have found many dozens of nests of this bird throughout southern California. Along the western slopes of the Sierra Nevadas in Tulare County, this grosbeak is an abundant nester. Most of the nests I have found have been in manzanita bushes or in willows. The nests are so thinly made on the bottoms that frequently the eggs can be seen from the ground when looking up through the bottom of the nest."

Weston (1947) says that such thinness was not observed in any of the eight nests that he studied in Strawberry Canyon.

Eggs: The usual set of the black-headed grosbeak consists of three or four eggs. Weston (1947) records the numbers of eggs in 192 sets. There were 18 sets of two, 96 sets of three, 75 sets of four, and only 3 sets of five eggs.

The measurements of 50 eggs average 24.7 by 17.7 millimeters; the eggs showing the four extremes measure 28.2 by 17.8, 24.4 by 19.6, 21.8 by 17.8, and 22.9 by 15.8 millimeters.

Incubation: This is shared by both sexes alternately during the day and is done by the female alone at night, according to Weston (1947). He says that incubation starts with the laying of the next to the last egg. "On an average day the eggs are incubated about 99 percent of the time, about 40 percent of the time by the male and 60 percent by the female. The average length of each incubation period of the male is close to 20 minutes, of the female 25 to 30 minutes." Both sexes occasionally sing at irregular intervals while on the nest, and are thus helpful in locating the nests. "Although the male sings while alone at the nest, the female usually sings only while the male is in the near vicinity. * * * The eggs begin hatching on the twelfth day of incubation. In each of three nests containing three eggs each, the last egg hatched twenty-four hours after the others." In some other cases, the eggs hatched "within a few hours of one another."

S. F. Rathbun writes in his notes for June 3, 1893: "This morning I found the nest of a black-headed grosbeak. The nest was built in the fork of a willow sapling at a height of some 10 feet, and the male bird could be plainly seen on the nest. I shook the sapling lightly, expecting to see the bird fly off, but such proved not the case, and neither did it occur when it again was shaken, so I took my knife and carefully cut the sapling, lowering it to the level of my face, not more than a foot away; and only when my free hand was advanced toward the bird (lid he fly, but only to alight on a limb a few' feet distant."

Young: In his summary, 'Weston (1947) writes: "Both sexes care for the young. During the first four days after hatching, young are fed with a sdft mash. On the fourth (lay, whole material is introduced into the diet. Early in the nestling period, fecal sacs are eaten by either parent. As the young develop, both parents spend progressively longer periods off the nest. The nestling period is twelve days. After departure from the nest the young follow the female."

Mrs. Wheelock (1912) says: "From watching the adults gather insects for the young, I am confident that so long as they remain in the nest, they are fed upon an animal diet, and for the first few days by regurgitation. In a little less than two weeks they hop out onto the small branches, and by instinct are soon pecking at every green thing in sight. For some time they seem to keep with the adults, being fed and guarded tenderly by them."

Plumages: James Lee Peters contributes the following: "The grayish-white natal down is succeeded by the juvenal plumage in which the sexual dimorphism is already apparent; the juvenal male nearly resembles the female and differs from the adult male in spring plumage in possessing a broad median coronal stripe of buffy bordered laterally with black, a white supraorbital stripe and gray ear coverts; the dorsal plumage is streaked rather than blotched, the black areas reduced and duller in color; the nuchal band is like the crown stripe; under parts much paler becoming white on throat and abdomen; wings and tail brown instead of black, the white spots and markings reduced in size; the lemon-yellow under-wing lining is as in the adult, but the spot of that color on the abdomen is lacking. The juvenal female is not very different from the adult female, but is duller below and with more and wider streaks on breast and flanks; the yellow abdominal patch is absent.

"The juvenal plumage is immediately followed by the immature or first-winter plumage which is acquired by a complete molt of the body feathers, but the wings and tail of the juvenal plumage are retained. In this plumage the sexes are somewhat similar above; the feathers of the upper surface with wide black centers and broad brownish edgings; below huffy cinnamon somewhat paler than in the adult; posterior portion of flanks streaked in the male; flanks, and, to a lesser extent, breast streaked in the female; the lemon-yellow abdorninal spot is acquired. The inimnature plumage is probably completely assumed by October.

"The first nuptial plumage is acquired (luring late winter and early spring by a partial molt of feathers of throat, sides of head, ear coverts, wing coverts, and tertials; sometimes one or more tail feathers with their corresponding coverts are renewed at this time; other changes in the bird's appearance are by wear. Males in the first nuptial plumage may be readily distinguished by their brown wings, brown or brown-and-black tails, and the fact that the top of the head retains traces of coronal stripe. Adult second-winter plumage is acquired by a complete molt involving wings, tail, and the entire body plumage; it is probably complete by October. At this time the black head, wings, and tail of the male, the latter with the conspicuous white blotches on the two outer pairs, are assumed. This plumage is essentially similar to the nuptial plumage which is acquired by the wearing off of the pale feather edges of head and upper parts."

Food: For his report on the food of the black-headed grosbeak, Prof. F. E. L. Beal (1910) examined the contents of 225 stomachs.

These stomachs contained about 57 percent of animal matter to 43 of vegetable. The animal matter is composed of insects and spiders, with a few traces of vertebrates. Insects, such as beetles, scales, and caterpillars, constituted nearly 53 of the 57 percent of animal food.

Of the animal food, beetles are the largest item. They were found in 190 of the 225 stomachs. Of these, predatory ground beetles (Carabidae) were found in 16 stomachs, and ladybird beetles (Coccinellidae) in 2. To offset the destruction of these useful insects, the 12-spotted diabrotica, which often does serious injury to fruit trees, was found in 109 stomachs. Many weevils were found, and great numbers of several species of leaf beetles (Chrysomelidac). To this family belongs the notorious Colorado potato beetle, which at one time seemed likely to ruin the potato industry of the East. * * * When the potato beetle finds its way into California, as eventually it undoubtedly ~vill, the black-headed grosbeak is the bird most likely to become its active enemy.

Hymenoptera in the form of bees and wasps with a few ants aggregate less than 2 percent. A worker honeybee was found in one stomach. Scale insects amount to 19.83 percent, or practically one-fifth of the whole food. Most of these were the black olive scale (Saissetia dccc), but a few were the plum and prune scales (Lecaneum corai and L. prainesurn). So persistently are scales eaten by this bird that they were found in 142 of the 225 stomachs, or 63 percent ofall. * *

Caterpillars, pupae, and a few moths aggregate 7.7 percent. * * * Pupae or larvae of the codling moth were found in 26 stomachs, one stomach containing the remains of 29. Flies, grasshoppers, a few other insects, spiders, and miscellaneous creatures make up something more than 1 percent.

Of the vegetable food, he says:

Cultivated fruit amounts to 23 percent of the grosbeaks food for the six months that it stays in the North. * * * Cherries appear to be the favorite fruit, as they were contained in 42 stomachs. Figs were identified in 24 stomachs, blackberries or raspberries in .23, strawberries in 2, apricots in 1, and prunes in 1. * * * During cherry season these birds were almost constantly in the trees eating cherries. They do not appear to attack apricots, peaches, and prunes so extensively, but they feed freely on figs later in the season. Blackberries and raspberries are taken whenever possible, but mostly in July and August, after cherries are gone. * * * The only wild fruit identified was the elderberry (Sambucus), which constitutes the bulk of this item, and was found in 26 stomachs.

Seeds of various weeds and some grain constitute 14.7 percent of the food. Oats were found in 9 stomachs and wheat in 7, hut the amount was insignificant. The rest of the vegetable food consists of the seeds of more or less troublesome weeds, of which the grosbeak eats a very considerable quantity.

The stomachs of 17 nestlings were incladed in the study. The youngest birds had been fed almost entirely on insects, averaging more than 90 percent, mainly caterpillars and pupae. The older birds had been given a larger percentage of beetles and other insects.

Weston (1947) states that, in Strawberry Canyon, a "high percentage" of the food of this grosbeak consisted of the California oak moth, which defoliates the live oaks, lie saw them eating the wormlike larvae, and found pupa cases broken open. "Innumerable winged adults were also captured and eaten, although the wings were dropped before the bodies were eaten." He also lists 18 species of plants, parts of which were eaten.

In the Yosemite region, Grinnell and Storer (1924) noted blackheaded grosbeaks "feasting on the wild blackberries which were then ripening in abundance." And "two males were seen feeding upon the hearts of cherry blossoms. These birds were working rather rapidly and a blossom would drop every fifteen of twenty seconds." And, in western Nevada, it was observed by Robert Ridgway (1877) "to feed, in May, upon the buds of the grease-wood (Obio'ne conjertifolia)."

Joe T. Marshall, Jr. (1957), discussing the species without racial identification, states that it eats numerous pine seeds evidently taken from open cones. He says, further, "A pair fed on the green seeds of a prostrate milkweed. Another grosbeak ate mistletoe in a ponderosa pine. * * * In a flowering Arizona oak, one * * * frequently reached toward the catkins with its bill. This female was not at first recognized as a bird, for it resembled instead a chipmunk or small squirrel by constantly keeping its head down and body horizontal; it actually crawled along the horizontal twigs." He also describes two migrant adult males which fed in Prunus virens, remainmg within a few yards of each other for 45 minutes. The birds were searching for certain leaves rolled up half their length, each enclosing a large green caterpillar. "Each bird would fly to a slender twig, bending itso as to cling head-down: as it rocked up and down it would deftly pluck the leaf and then fly a few inches to normal posture on a steady twig. With a few quick movements of the bill the grosbeak would tear open the rolled up leaf, discard it with a shake of the head, and wind up with the caterpillar in its mouth. It subdued each caterpillar by biting along its length, then swallowed it whole. These dexterous operations were achieved entirely by the bill with no help from the feet, nor was there any resting or pounding of the prey against the twig." Marshall also mentions a bird joining with various other species in an attack on a flight of large termites. This bird attempted its captures by comparatively clumsy leaps and short flights from the top foliage of oaks.

Economic status: Beal (1910) writes in his summary:

In summing up the economic status of the black-headed grosbeak, the fact that it eats a considerable quantity of orchard fruit can not be ignored. * * * To offset its fruit eating, it eats habitually and freely the black olive scale, the codling moth, and the 12-spotted diabrotica, three pests of California fruit culture. * * * Should it ever become so plentiful as to cause serious loss, no attempts should be made to destroy the bird, but attention should be directed to devices for protecting the fruit, thus leaving the bird to continue its good work in the destruction of insects. So active an enemy of insect pests as is the grosbeak can not well be spared, especially in view of the possibility of an invasion of the State by the Colorado potato beetle.

W. L. McAtee (1908) gives a very full account of the food of this grosbeak, and remarks that "for every quart of fruit eaten, more than 3 pints of black olive scales and more than a quart of flower beetles, besides a generous sprinkling of codling moth pupae and cankerworms fall prey to this grosbeak."

Behavior: That the black-headed grosbeak is a close sitter on its nest, devoted to its charges, is shown by Rathbun's experience with it as mentioned above. It is not shy around houses and in orchards and seems to have no fear of human beings. It comes readily to feeding stations, where it is very tame and where it dominates other birds and sometimes quarrels with others of its own species. Its beneficial feeding habits, in spite of its few faults, and its delightful song make this handsome bird a desirable companion about the house and garden, where it should be encouraged.

Voice: Its song closely resembles the rich song of its eastern relative, the rose-breasted grosbeak; to a lesser extent the song resembles that of the robin and is reminiscent of that of the western tanager, but it is richer and more varied than either. Grinnell and Storer (1924) write: "The black-headed grosbeak possesses a rich voluble song that forces itself upon the attention of everyone in the neighborhood. In fact at the height of the song season this is the noisiest of all the birds. The song resembles in some respects that of a robin, and novices sometimes confuse the two. The grosbeak's song is much fuller and more varied, contains many little trills, and is given in more rapid time. Now and then it bursts forth fortissimo and after several rounds of burbling, winds up with a number of 'squeals,' the last one attenuated and dying out slowly."

S. F. Rathbun (MS.) describes the song as "a succession of rich and clear whistling notes given rapidly, now and then having trills injected, closing with a few rough notes. The song has a bold and joyous quality which is very noticeable." One that he listened to in early June began to sing at 3:55 a.m., 15 minutes before sunrise, and "sang from the time it began, almost without any intermission, for a period of 3 hours, each rendition of its song being followed by another with scarcely a perceptible pause between. After this first burst of more or less continuous singing, there began to be intermissions of a few seconds between the songs. As the day wore on, the bird sang less often, but it was not until 7 hours had passed that the song was heard only at times. Then it became disconnected, only the whistling notes being beard."

Weston (1947) says:

Length of individual songs varies considerably. The shortest that I have timed lssted one second, the longest eighteen; the average song is five seconds in length. The intervals between songs in series vary from one second to twentyseven seconds. In general, songs in the early morning are longer, louder, and richer in quality than those at other times in the day. * *

In general, the songs of female grosbeaks are infrequent and never more than four seconds in duration and are never loud. They are uttered while the female is incubating or brooding, usually as the male comes to take his place on the eggs or young. Several times during nest-building, the female uttered songs in the vicinity of the nest and always in the presence of the male. The female will occasionally sing while foraging in the peripheral foliage of trees, but only while the male is close by. * *

The common call-note, a sharp spic, closely resembles that of the Rose-breasted Grosbeak. * * * It is commonly emitted while both sexes are foraging and at these times the calls are especially frequent, being repeated over and over at regular intervals.

Fall: The same observer states: "Fall departure is apparently irregular. Late in the season all individuals are quiet. The males cease singing after mid-July and are the first to leave, generally disappearing late in July. Females and young remain several weeks longer and usually begin to leave in mid-August. In the past thirtytwo years, the last-seen dates at Berkeley have ranged from August 11 to October 9. Records after early September are probably those of transients rather than local residents."

Rathhun tells me that the black-headed grosbeaks leave the vicinity of Seattle between September 5 and 20.

DISTRIBUTION
Range: Pacif Ic slope from southwestern British Columbia to Oaxaca.

Breeding range: The black-headed grosbeak breeds from southwestern British Columbia (Quinsam Lake, Coquitlam) south along the Pacific coast to northern Baja California (Sierra San Pedro Martir); east in California to Owens Valley and the San Bernardino Mountains.

Winter range: Winters from southern Baja California (La Paz), southern Sonora (Tesia), and southwestern Chihuahua south to Oaxaca (Mitla).

Egg dates: British Columbia: 3 records, June 3 to June 5.

California: 200 records, April 23 to July 10; 102 records, May 5 to May 23.

Washington: 6 records, June 4 to July 4.

ROCKY MOUNTAIN BLACK-HEADED GROSBEAK
PHEUCTICUS MELANOCEPHALUS MELANOCEPHALUS (Swainson)
HABITS

A. J. van Rossem (1932) has shown that the type name, as given above, applies to the Rocky Mountain subspecies and not to the California race. The Rocky Mountain bird is larger than the California form and the postocular stripe is usually absent.

Swarth (1904) says of its haunts in the Huachuca Mountains of Arizona: "It is rather singular that though in California this species is most abundant in the willow regions of the low lands, here it is preeminently a bird of the higher mountains, and, even during the migrations, of very rare occurrence in the lower valleys. During the summer it is most abundant in the higher parts of the mountains, seldom breeding below 6000 feet; but soon after the young leave the nest a downward movement is begun, and up to the middle of August these Grosbeaks fairly swarm in some of the lower canyons, young and old gathering together in enormous, though loose and straggling flocks."

Mrs. Bailey (1928) says that, in New Mexico, this grosbeak "is characteristically a bird of the Upper Sonoran oak, juniper, and nut pine region, and of the thick cottonwood groves and deciduous trees and bushes along streams."

In southwestern Saskatchewan, we found at least three pairs of black-headed grosbeaks nesting in the timber along Maple Creek; I collected one male and a set of three eggs; Dr. Bishop and Dr. Dwight, also, collected a pair of these birds and two eggs on another creek in this vicinity.

The nesting habits, eggs, food, and general behavior of the Rocky Mountain grosbeak are apparently similar to those of the more western subspecies.

In the timber along Maple Creek, southwestern Saskatchewan, on June 16, 1906, we found a nest of this grosbeak containing two eggs.

The nest was much like that of the rose-breasted grosbeak and was placed about 7 feet from the ground in a slanting fork of a thorny bush in a thick grove of small poplars and other bushes. The male was sitting on the eggs, and it was only with some difficulty that I could drive him far enough away from the nest to shoot him; he eventually fell into the nest and broke the eggs.

We had seen this grosbeak in that same region the previous year and heard its song, which to my ears was exactly like the robin like song of the rose-breasted grosbeak. Mrs. Bailey (1928) writes:

The call of the Blackheaded is as thin and weak as his song is rich and full of personality. At its best, the song excels in finish and musical quality. * * * As a violinist, lingering to perfect a note, draws his bow again and again over the strings, so this rapt musician dwelt lovingly upon his highest notes, trolling them over till each was more exquisite and tender than the last, and the ear was charmed with his love song. In Arizona, Mr. Henshaw had the good fortune to listen to some of the delightful concerts with which the birds closed each day. In the pine woods near Camp Apache, he tells us, 'just after the sun had fairly sunk below the woods, these Grosbeaks ascended to the tops of the tallest pines, and thence sent forth their sweet strains till long after dusk had settled down upon the deep forest~." (1875, p. 297).

Eggs: This species usually lays three or four eggs, but sometimes only two, and more rarely five, to a set. They are ovate with occasionally a tendency to short-ovate, and have a slight gloss. The ground may be "Etain blue," "pale Nile blue," or "pale Niagara green," and well speckled, spotted, or blotched with browns such as "raw umber," "Argus brown," "Mummy brown," or "Prout's brown," with some underlying markings of "olive gray" or "mouse gray." The markings are generally well scattered over the entire eggs and usually in the form of speckles or spots. On most eggs the spots become more concentrated toward the large end where, on occasion, they form a. solid cap. The measurements of 50 eggs average 25.1 by 17.9 millimeters; the eggs showing the four extremes measure 27.9 by 17.8, 25.4 by 18.8, 23.0 by 17.1, and 27.9 by 16.3 millimeters.

DISTRIBUTION
Range: Southwestern Canada to Ecuador, Colombia and Venezuela.

Breeding range: The Rocky Mountain grosbeak breeds from southeastern British Columbia (Okanagan Landing, Creston), northwestern Montana (Flathead Lake), southeastern Alberta (Walsh), southwestern Sasatchewan (Maple Creek), northeastern Montana (Glasgow), and northwestern North Dakota (Charlson) south through eastern Washington and eastern Oregon to extreme eastern California (White Mountains, Clark Mountain), central and southeastern Arizona (Prescott, Huachuca Mountains), and the Mexican Plateau to Guerrero (Amojileca) and Oaxaca (Cerro San Felipe); east to central Nebraska (Greeley) and central Kansas (east to Cloud and Harvey counties), western Oklahoma, western Texas (Midland County), and Tamaulipas (La Joya de Salas).

Winter range: Winters from southern Sonora (Alamos), southern Chihuahua (Chihuahua), and Nuevo Le6n (Mesa del Chipinque) south to Guerrero and Qaxaca.

Casual records: Casual north and east to eastern North Dakota (Fort Totten), western Ontario (Kenora), eastern Missouri (St. Charles County), central Oklahoma (Fort Cobb), and central Texas (Menard, Somerset). Casual in winter in Texas, Arkansas, Louisiana, Mississippi, Alabama, Florida, South Carolina, Virginia, Maryland, Pennsylvania, New Jersey, New York, Connecticut, and Massachusetts.

Migration: The data deal with the species as a whole. Early dates of spring arrival are: Nuevo Le6n: March 24. Coahuila: Sierra del Carmen, April 13. Baja California: Concepcion Bay, April 2; Agua Verde Bay, April 12. Florida: southern peninsula, April 13. Alabama: Booth, May 4. Texas: Kerrville, April 30. Oklahoma: Cheyenne, May 10. Kansas: Hayes, April 26 (Kansas median for 17 years, May 5). Nebraska: Superior, April 18. South Dakota: Aberdeen, April 21. Manitoba: Treesbank, May 30. Saskatchewan: Nipawin, June 6. New Mexico: Chloride, April 28; Los Alamos, May 2 (median of 8 years, May 7). Colorado: Grand Junction, April 20. Utah: Green River, May 6. Wyoming: Torrington, May 12 (average of 11 years, May 21). Idaho: Potlatch, May 10 (median, May 19). Montana: Fort Custer, May 14. California: San Francisco Bay area, April 2. Nevada: Mercury, April 11. Oregon: Yamhul County, April 27. Washington: Pullman, May 9; Everson, May 12 (median of 6 years, May 19). British Columbia: Victoria, May 1.

Late dates of spring departure are: Veracrux: Las Vigas, April 24. Sinaloa: Cosal~, May 13. Guerrero: Chilpancingo, May 6. Baja California: La Paz, May 4.

Early dates of fall arrival are: Texas: Austin, August 26. Missouri: St. Charles County, September 6. Louisiana: Bonnet Carr~ Spillway, October 25. Florida: Pensacola, October 1. Baja California: La Paz, July 22. Sinaloa: October 4. Guerrero: August 26 Late dates of fall departure are: British Columbia: Okanagan Landing, September 15. Washington: Pullman, September 6; Everson, September 5 (median of 5 years, September 3). Oregon: Multnomah, September 28. Nevada: Mercury, October 4. California: Point Bonita, October 20. Montana: Gold Creek, Powell County, August 27. Idaho: Potlatch, September 13. Wyoming: Lusk, October 6. Colorado: Grand Junction, October 2. New Mexico: Los Alinos, September29 (median of 9 years, September 13). South Dakota: White River, September 2. Nebraska: Red Cloud, September 25. Kansas: September 18 (median of 5 years, September 2). Oklahoma: Kenton, September 24. Texas: Somerset and San Antonio, September 27. Missouri: Jefferson County, September 22. Massachusetts: Martha's Vineyard, November 11. New York: 4-Oak Island, October 20. New Jersey: Island Beach, November 2. South Carolina: October 15. Alabama: Montgomery, October 4. Florida: Miami, November 26; northern peninsula, October 26.

Egg dates: Arizona: 16 records, May 20 to June 21; 10 records, May27 to June 7.

Colorado: 22 records, May21 to July 17; 13 records, June 2 to June 12.