450 Birds of Colorado 
again for the south in September. It nests chiefly in the plains but 
also in the mountains, perhaps up to 9,700 feet (Breckenridge, Carter), 
It is common throughout the State from Routt co. (Warren 08) to 
La Plata co. (Gilman), and from Weld co. (Markman) to Baca co. 
(Warren 06), and Costilla co. (Henshaw). In Mesa co., where it is 
the commonest Warbler, it breeds up to 7,000 feet. 
Habits.—The Yellow Warbler is perhaps the best 
known of all the family owing to its conspicuous 
coloration and familiar habits. It is fond of frequenting 
parks and gardens, and is very common about the 
suburban paris of towns, where it frequently builds 
its nest. Its more natural surroundings in Colorado 
are willow and cotton-wood trees and bushes along 
streams, but it does not care for thick forest or pine 
woods. 
Like other Warblers, its food consists entirely of insects, 
and it is always busy searching for these among the 
leaves and smaller branches of the trees. The song is 
tather simple, Bat sweet and lively and highly character- 
istic, and is indulged in even in the middle of the day. 
The nest, according to Gale, is placed in a crotch of 
a small tree, or more often in a low bush, usually a willow 
or cotton-wood ; in the latter case it is pensile, being 
fastened to the surrounding twigs at the rim. It is 
woven of wild hemp or vine stems and grasses, and 
lined with the cotton from the cotton-wood trees, and 
is a light, compact and well-built structure. 
Fresh eggs are to be met with about June 12th (Dille) ; 
the clutch is usually four, sometimes five, and the eggs 
are greyish to greenish-white, marked with spots, splashes 
and blotches of various shades of lilac and brown. They 
average ‘68 x ‘50. This Warbler is one of the most 
frequent victims of the parasitic Cow-bird, and appears 
to realize the fact, as it is one of the few birds which 
constantly build a second and sometimes a third story 
