598 MICHIGAN BIRD LIFE, 
is commonly placed in some low bush or shrub, often within two or three 
feet of the ground, rarely ten or fifteen feet up in a fruit tree or shade tree. 
It almost always consists largely of light-colored flaxen or hempen ma- 
terials, gathered from various weed-stalks, and is very bulky, with 
thick walls and a deep hollow. It is lined with similar but finer fibrous 
materials, to which is added a large amount of plant-down which is often 
compactly felted so that the interior is very smooth and warm. The eggs 
are four or five, bluish or greenish white, rather coarsely spotted with 
lilac, brown and black. They average .66 by .48 inches. 
The Yellow Warbler is constantly victimized by the Cowbird, and in 
places where this parasite is abundant many deserted nests are found 
containing from one to four eggs of the Cowbird, with or without some 
of the warbler. This frequent desertion of the nest and the building 
of a new one apparently explains the late date at which fresh eggs are 
often found, the first to the middle of June; we have no conclusive evidence 
that the bird ever rears two broods. As is well known, this warbler not 
infrequently covers a Cowbird’s egg with a new layer of material in the 
bottom of the nest, raising the rim of the nest correspondingly, and instances 
have been known where this has been done a second time, making a three- 
storied nest. 
The food consists mainly of insects and spiders, although small fruits 
are taken sparingly; we have never heard a complaint of damage to garden 
fruits by this bird. Forbes has shown that, like most other birds, it makes 
use of the food which is most easily obtained, and in an orchard overrun 
with canker-worms he found that these larve formed two-thirds of the 
whole food of the Yellow Warbler; the other insects were mainly beetles, 
but there was 6 percent of spiders. 
This bird is frequently confounded with the Goldfinch, which is also 
called Yellow-bird, but the two species have really little resemblance in 
song or habits. A comparison of the description of the Yellow Warbler 
with that of the Goldfinch will show how unlike the two birds really are, 
in spite of the fact that both show a large amount of yellow. 
TECHNICAL DESCRIPTION. 
Male in spring: Forehead, crown, and entire under parts clear canary-yellow; throat 
unspotted; breast and sides thickly streaked with reddish brown; back and upper tail- 
coverts greenish yellow; wing-feathers dusky, the tertials margined externally with yellow; 
tail-feathers brownish black on outer webs, the inner webs yellow. Female: Similar 
but forehead and crown greenish-yellow like the rest of the back, and the yellow under 
parts faintly or not at all streaked with brown; wings and tail as in the male; size but 
shghtly less. Young birds are duller and browner, but may be recognized in any plumage 
by the yellow tail-markings as above. 
Length 4.50 to 5 inches; wing 2.35 to 2.65; tail 1.80 to 2.10. 
272. Black-throated Blue Warbler. Dendroica cerulescens czrulescens 
(Gmel.). (654) 
Synonyms: Motacilla cwerulescens, Gmelin, 1789.—Sylvia canadensis, Wils., Nutt., 
Aud.—Sylvicola canadensis, Rich—Dendroica canadensis, Baird, 1858.—Sylvia pusilla, 
Wils., 1912.—Sylvia sphagnosa, Bonap., 1824. 
The male has dark blue upper parts, clear black throat, breast and sides, 
and white belly. Several of the outer tail-feathers have white marks, and 
there is a very constant and characteristic white spot in the wing at the 
base of the primaries. The female has olive (sometimes glossed with 
