BLACK-THROATED BLUE WARBLER. 
654. Dendroica cerulescens. 5%, inches. 
Male, gravish blue above and with a _ black face, 
throat, breast and sides; female, grayish olive above, 
whitish below. Both sexes always have a white patch 
or speck at the base of the primaries. 
You will find these birds in damp woods or swamps, 
or less often in parks or open woods. They are usually 
seen at low elevations in scrubby underbrush. Their 
notes are very peculiar and will draw attention to them 
anywhere. 
Song.—A deep grating whistle with a sharply rising 
inflection, ‘‘zee-zee-zwee.” 
Nest.—In deep, swampy woods, especially common 
in laurel; of grape vine bark and rootlets lined with 
fine black roots and hair; the four eggs are white or 
buffy white with reddish-brown spots and blotches. 
Range.—EKastern N. A., breeding from Connecticut 
(sparingly) and Michigan north to Labrador and Hud- 
son Bay; winters in Central America. 654a. Cairns 
Warbler (cairnsi) is said to be darker on the back; 
found in the southern Alleghanies. 
