458 Birds of Colorado 
and tail dusky, the coverts tipped with white, forming a double wing- 
bar ; the outer three pairs of tail-feathers largely white ; under-parts: 
white, sharply defined from the black throat ; sides streaked with black ; 
iris brown, bill black, legs dusky. Length 4-30; wing 2-45 ; tail 1.90 ;. 
culmen -4; tarsus -7. 
The female resembles the male, but usually has less black on the 
head, and a wash of brown on the back ; the throat and breast are 
mottled black and white. Young birds and adults in the fall have 
less black on the head and cheeks, and have the throat mottled black 
and white. 
Distribution.—A western Warbler, breeding from British Columbia. 
to Lower California, and eastwards to Colorado and New Mexico, 
migrating south in winter as far as Oaxaca and Vera Cruz in Mexico. 
In Colorado the Black-throated Grey Warbler is a rare bird ; arriving 
from the south in May, and ranging up to 9,500 feet at Silverton in 
San Juan co. It has been reported from Idaho Springs, May 23rd, 
by Trippe, and from Loveland on May 9th by W. G. Smith, while 
Aiken records it from El] Paso and Fremont cos., where he tells me 
that he believes that it breeds among the pifion hills north and east 
of Cation City, but neither he nor any other observer has taken the 
nest in the State. Cary reports that he saw or took this bird at Douglas. 
Springs in September, in Sinbad Valley in July, at Coventry, and at 
Mesa Verde, 7,000 feet, all localities in the west of the State. 
Habits.—Aiken gives the following account: ‘“ Rather 
a rare migrant in Colorado; a few probably remaining 
to breed. I have never seen it anywhere but on the 
mesas and foothills that are covered with low, scraggy 
pifion pines. The male as he searches for insects on 
leaf or limb repeats at intervals a singular but withal 
a very pretty song, with something of a metallic rig 
in it. Shy and retiring in its habits, and frequenting 
pifion groves so dense that one can scarcely see a dozen 
yards ahead, it is easily overlooked and requires con- 
siderable perseverance to secure.” In Arizona it is 
reported to nest in dense scrub-oak as well as high up in 
pine trees. The nest resembles that of the Yellow 
Warbler, and usually contains four eggs—white, delicately 
marked with specks of red-brown and purplish, and 
measuring about ‘69 x ‘50. 
