396 
VIREOS 
of streams, or in shade-trees along streets. Eggs: 4 or 5, white, spotted 
around larger end with reddish, dark brown, and lilac. 
Colorless as this small leaf-tinted bird may seem in coat, character, 
and song, its voice is nevertheless one of the sunny warbled rounds 
that gives good cheer to the western mountain forests. 
In Colorado, Prof. Cooke says, it breeds sparingly on the plains 
and abundantly in the mountains up to 10,000 feet, especially in the 
aspens. On San Francisco Mountain, Arizona, Dr. Mearns found it 
in fall in the rank growth of annuals along streams in company with 
terrestrial warblers. 
But, though a mountain dweller, the little vireo is also a village 
bird, leaning over and craning its neck to examine the leaves for 
worms as carefully in a Utah garden as in the retirement of the 
forest. 
Subgenus Lanivireo. 
Spurious primary if present decidedly shorter than tarsus; wing with two 
white bars. 
629. Vireo solitarius (Wils.). Blue-headed Vireo. 
Adults. — Top and sides of head dark gray in sharp contrast to white loral 
streak, orbital ring and throat; back olive green; wings with two white bars ; 
under parts clear white, shaded with olive and yellow on sides and flanks. 
Young in first winter: anterior upper parts grayish brown, under parts dull 
buffy white. Length : 5-6, wing 2.90-3.00, tail 2.10-2.20, bill from nostril 
.28-.30. 
Distribution. — Breeds from Great Slave Lake and Hudson Bay to south¬ 
ern New England and the northern part of the lake states, and from the 
Atlantic coast to Dakota; migrates to Guatemala. 
Nest. — In woods, in undergrowth, or hung from lower branches of small 
trees, like that of the red-eye, but often decorated with catkins. Eggs : 
usually 5, white, spotted mainly with reddish brown around the larger end. 
Food. — Chiefly insects. 
629a. V. s. cassinii ( Xantus ). Cassin Vireo. 
Adults. — Top and sides of head gray in sharp contrast to white of loral 
streak , orbital ring , and throat; back dull 
olive green; wings with two clear white 
bands; under parts clear white, washed 
with yellow and olive on sides and flanks. 
Young in first winter: dull grayish brown 
above, dull buffy below. Length: 5.00- 
5.60, wing 2.85-3.00, tail 2.10-2.30, bill 
from nostril .28-.31, tarsus .70-.78. 
Distribution. — Breeds from British Co¬ 
lumbia and Idaho south along the Pacific 
coast region and Nevada to Lower Cali- 
Fig. 491. fornia; migrates to Arizona, New Mexico, 
and northern Mexico. 
Nest. — In oaks, manzanita, and buck brush, pendant, compactly woven 
and lined with light-colored grasses, decorated with pieces of white cocoon. 
Eggs : 4 or 5. 
