244 



BIRDS OF AMERICA 



brown forming a distinct patch ; rump and lesser wing- 

 coverts, dull blue, the former rather brighter, passing 

 into bright blue on upper tail-coverts and tail ; middle 

 and greater wing-coverts and inner quills, dusky gray- 

 ish-brown edged with paler brownish-gray or bluish ; 

 secondaries, dull bluish ; the primaries, lighter and 

 brighter blue narrowly edged with whitish, the outer- 

 most broadly edged with white; sides of head, throat, 

 center portion of upper chest, and breast, light brownish- 

 gray passing into dull grayish on chin; sides of chest 

 and breast and more or less of sides, dull cinnamon- 

 rufous; abdomen and flanks, pale grayish-brown; under 

 tail-coverts pale dull grayish-blue, edged with pale 

 brownish-gray, usually with a dusky shaft-streak; 

 under wing-coverts, dull grayish-blue ur bluish-gray ; 

 bill and iris as in male. 



Nest and Eggs. — Nest: In holes of dead trees, 

 between the trunk and loose bark, and, in the more 

 settled parts of its range, in boxes supplied for the 

 purpose; comprised of sticks, straw, hay, or any 

 similar material. Eggs: 4 or 5, uniform pale blue, 

 somewhat deeper in shade than those of the Eastern 

 Bluebird. 



Distribution. — Pacific coast district from Los An- 

 geles county, California, to British Columbia, chiefly 

 from the coast to the western slope of the Sierra 

 Nevada and Cascade ranges, but extending eastward 

 through eastern Oregon and Washington to northern 

 Idaho and western Montana (breeding) ; northward to 

 British Columbia (X'ancouver Island); southward in 

 winter as far as San Pedro Martir Mountains, Lower 

 California. 



This form so strongly resembles the Common 

 Bluebird of the Eastern States that only a trained 

 eye would detect the color difference between -the 

 two birds. Its habits and disposition, too, are 

 virtually those of the eastern bird, nor is there 

 any material difference between the economic 

 status of the two, both undottbtedly doing very 

 valuable work in the destruction of insect-pests. 



In an examination of 217 stomachs of the 

 JVestern Bluebird, animal matter ( insects and 

 spiders) was found to the extent of 82 per cent, 

 and vegetable matter to the extent of 18 per 

 cent. The bulk of the former consisted of bugs, 

 grasshoppers, and caterpillars. Grasshoppers, 

 when they can be obtained, are eaten freely dur- 

 ing the whole season. Caterpillars also are a 

 favorite food and are eaten during every month 



of the year; March is the month of greatest con- 

 sumption, with 50 per cent., and the average for 

 the year is 20 per cent. Two stomachs taken in 

 January contained 64 and 50 per cent., respec- 

 tively, of caterpillars. Beetles also are eaten and 

 comprise mostly harmful species. The vegetable 

 matter consists of weed seeds and small fruits. 

 In December a few grapes are eaten, but elder- 

 berries are the favorites whenever they can be 

 found. 



The southern Rocky Mountain region has two 

 slightly differing forms of Western Bluebird. 

 The Chestnut-backed Bluebird {Sialia mcxicaiia 

 bairdi ) ranges through Utah, Colorado, and 

 western Texas south into Mexico ; the San Pedro 

 Bluebird (Sialia iiicxicaiia anahchr) breeds in 

 San Pedro Martir Mountains. 



MOUNTAIN BLUEBIRD 

 Sialia currucoides (Bcclistc'm) 



A. O. U. Xumbe 



Other Name. — .Arctic Bluebird. 



General Description. — Length. y% inches. Male: 

 Upper parts, cerulean-blue ; under parts, turquoise-blue 

 and white. Fe.m.'^le: Upper parts, gray and tur- 

 quoise-blue ; under parts, brownish-gray and white. 

 Bill, small and slender; wings, long and pointed; tail. 

 shorter than wing, distinctly notched ; legs, short. 



Color. — Adult M,\le : Above, plain rich cerulean- 

 blue, the wings and tail slightly more cohalt-blue ; shafts 

 of wing- and tail-feathers, black, and terminal portion 

 of primaries, dusky; sides of head, chin, throat, chest, 

 breast, and sides plain turquoise-blue, decidedly paler 

 and less bright than color of upper parts; abdomen, 

 hinder flanks, anal region, and shorter under tail- 

 coverts white ; longer under tail-coverts pale turquoise 

 tipped or margined with white ; bill, black ; iris, dark 



brown, .'^dult Female: Crown, hindneck. back, and 

 shoulders plain mouse-gray, sometimes faintly tinged 

 with greenish-blue; rump, upper tail-coverts, tail, and 

 wing (except inner feathers), turquoise-blue; inner 

 quills and greater wing-coverts, similar in color to back, 

 but darker, edged with paler, and sometimes tinged with 

 blue; lesser and middle wing-coverts dull greenish-blue, 

 or else dusky brownish-gray margined with bluish ; 

 an eye-ring of dull white; sides of head similar in 

 color to crown but rather browner; chin, throat, chest, 

 breast, and sides, pale brownish-gray passing into dull 

 white on abdomen, hinder flanks, anal region, and under 

 tail-coverts, the longer of the latter with dusky shaft- 

 streaks and sometimes tinged with blue ; bill and iris 

 as in the male. 

 Nest and Eggs. — Nest : Placed in a hollow limb. 



