BLACK-THROATED BLUE WARBLER 133 



there are spots over the larger part of the entire shell while the 



small end of others is immaculate. The measurements are .69x49, 



.65x49, .66x49, .66x48." (Chamberlain.} (Figs. 35,36. Childs Coll.) 



Nesting Dates. St. Johns, N. B., June 16 (Chamberlain}. 



BIOGRAPHICAL REFERENCES 



(i) M. CHAMBERLAIN, Nesting Habits of the Cape May Warbler [in New 

 Brunswick], Auk, II, 1885, 33. (2) A. W. BUTLER, Birds of Indiana, 1043. 

 (3) C. J. MAYNARD, Warblers of New England, 15. (4) WM. BREWSTER, 

 Birds of the Cambridge Region, 331. 



BLACK-THROATED BLUE WARBLER 



DENDROICA OERULESCENS CvERULESCENS (Gmel.) Plate IX 



Distinguishing Characters. The <$, whether adult or young may always 

 be known by its black throat and blue back. In the adult ? the white spot on 

 the primaries above the primary coverts, is diagnostic. In the young $ this 

 spot is much reduced and at times not evident and such specimens possess no 

 obvious distinguishing mark. The bird in the hand, however, may be identified 

 by the bluish tone of the tail feathers in connection with other features 

 described beyond. Length (skin), 4.50; wing, 2.50; tail, 2.00; bill, .35. 



Adult <$, Spring. Upperparts dark grayish blue, the back and inner tail- 

 coverts at times with more or less black; tail black edged with blue, the three 

 outer feathers with large white patches near the tip of the inner web, the 

 next two usually with more or less white on the margin of the inner web; 

 wings black edged with blue; all but the outer primary with more or less 

 white basally, this on the second to seventh or eighth primaries appears as a 

 conspicuous white spot at the end of the primary coverts; cheeks, throat, and 

 sides black, rest of underparts white. 



Adult <$, Fall. Only slightly different from above; the back very nar- 

 rowly tipped with greenish, the throat and sides with white; black of throat 

 apparently somewhat less in extent. 



Young $, Spring. Young of the previous year may be distinguished from 

 fully mature males by remains of the greenish edgings generally to be found 

 on the upperparts, and particularly by the browner green-edged wing feathers, 

 which are evidently worn for one year. 



Adult $, Spring. Above dusky olive-green with a more or less evident 

 bluish tinge strongest on crown and upper tail-coverts; a narrow whitish line 

 from bill over eye, lower and upper part of eye-ring whitish; tail fuscous 

 margined with grayish blue, the outer feathers usually with white patches; 

 wings fuscous margined with greenish ; a white spot at the base of the primaries 

 at the end of the primary coverts generally evident but sometimes (in immature 

 specimens?) barely visible; underparts pale buffy yellowish or whitish, the 

 sides darker, the throat and sides of the breast rarely dusky. 



Adult $, Fall. Indistinguishable in color from adult $ in Spring. 



Young $?, Fall. Similar to adult $ in Fall but greener above, where 

 without trace of blue, dingy yellowish below, line over eye yellowish, white 

 wing-spot never large and conspicuous and sometimes concealed by the primary 

 coverts; white in tail much reduced. 



