THE BLACK-THROATED BLUE WARBLER. 225 



throat, lustrous black, this color extending in a broad lateral stripe to the tail ; rest 

 of under parts, including the axillary region, wliite; wings and tail black above, the 

 former with a conspicuous white patch formed by the bases of all the primaries 

 (except the first); the inner webs of the secondaries and tertials with similar patches 

 towards the base and along the inner margin ; all the tail feathers, except the inner- 

 most, with a white patch on the inner web, near the end. 



Female, olive-green above and dull-yellow beneath ; sides of head dusky-olive, 

 the ej^elids and a superciliary stripe whitisli ; traces of the white spot at the base of 

 the primaries and of the tail. 



Length, five nnd fifty one-hundredths inches; wing, two and sixty one-hun- 

 dredths; tail, two and twenty-five one-hundredths inches. 



This Warbler is not uncommon in the mountainous dis- 

 tricts of Massachusetts, from the middle to the end of May ; 

 and I found several specimens in the Green-Mountain coun- 

 try as late as the 10th of June. This occurrence, together 

 with the fact that it has been found, in the breeding season, 

 on Mount Holyoke, in Mass., and along the ridges in the 

 western part of this State, shows that it probably breeds, 

 sometimes at least, in Massachusetts. 



The individuals that I saw were in tall oaks and chest- 

 nuts, actively moving about tlu'ough tlie foliage, snapping at 

 flies and other insects : they often uttered a faint, drawling 

 weesy, weesy, and occasionally a louder chirp or clunky like 

 that of the Nashville Warbler. 



Being unacquainted with the nest and eggs, I give Audu- 

 bon's description of them : — 



" The nest is usually placed on the horizontal branch of a fir-tree, 

 at a height of seven or eight feet from the ground. It is composed 

 of slips of bark, mosses, and fibrous roots, and is lined with fine 

 grass, on which is laid a warm bed of feathers. 



" The eggs, four or five in number, are of a rosy tint, and, like 

 those of most other Sylvice, scantily sprinkled with reddish-brown 

 at the larger end. Only one brood is raised in a season." 



About the first week in September, this species leaves 

 New England on its southern migration. 



15 



