THE BLACK-THROATED BLUE WARBLER. 139 



No. 62. 



BLACK-THROATED BLUE WARBLER. 



A. O. U. No. 654. Dendroica caerulescens (Gmel.). 



Description. Adult male : Above, dark dull blue, occasionally spotted with 

 black on the back; extreme forehead, sides of head, chin, throat, sides of breast, 

 and sides, intense black ; remaining lower parts pure white ; wings and tail black- 

 ish, edged on exposed portions with blue or whitish; a large white spot at base 

 of primaries on both webs; secondaries and lower tertials broadly edged with 

 white; three outer pairs of tail-feathers broadly but decreasingly blotched with 

 white on inner webs ; bill black ; feet brown. Adult female in spring : Above 

 dull greenish blue ; no pure black anywhere ; sides of head dusky ; below white, 

 sordid, or with a bluish buffy suffusion ; white spot at base of primaries reduced 

 but still prominent. Adult female in autumn : Similar but with more yellow 

 everywhere; therefore dull olive-green above, dingy yellow below; brownish 

 washed on sides. Immature male: Like adult male, but upper parts greenish; 

 less black below. Immature female: Like adult female in autumn. Adult male 

 in winter : Above touched with olivaceous ; below black somewhat restricted ; 

 flanks touched with brownish. Length 4.75-5.50 (120.6-139.7); av. of five Co- 

 lumbus specimens: wing 2.53 (64.3); tail 1.86 (47.2); bill .39 (9.9). 



Recognition Marks. Medium size; black, dull blue, and white in masses 

 of male ; white spot at base of primaries in female. 



Nesting. Not found breeding in Ohio. Nest, of bark-strips, twigs, and 



f rasses, lined with fine rootlets and horse-hair ; placed in low bushes near ground. 

 ggs, 4 or 5, dull white, with spots and dots of olive-brown, chiefly wreathed 

 about larger end. Av. size, .68 x .51 (17.3 x 13.). 



General Range. Eastern North America to the Plains, breeding from north- 

 ern New England and northern New York northward to Labrador, etc. West 

 Indies and Guatemala in winter. 



Range in Ohio. Common spring and fall migrant. 



THE Warblers are a world unto themselves. \Vhen the semi-annual 

 flood-tide of migration is at its height, nearly all available space is occupied 

 by them as completely as tho no other sorts of birds existed. The spatial 

 exceptions are the open fields where Sparrows reign supreme, and open water 

 where none but web-footers and the Swallow kind may go. The portion 

 which falls to the Black.-throated Blue in the grand allotment consists of the 

 lower levels in the deeper forests, together with an added gratuity of outlying 

 evergreens wherever these may occur. Not but that the bird may appear as 

 a visitor in the tree-tops, or even as an inquisitive tourist in swampy recesses, 

 but these are not his home. 



The clear-cut, modest color-masses of the male bird are enough to awaken 

 enthusiasm in any beholder ; but the totally different pattern of the female with 

 her shifting olive-greens and dingy yellow, is apt to be confusing. The white 



