THE WARBLING VIREO. 273 



brownish-black. The measurement of four eggs in a nest 

 collected in Milton, Mass., are .84 by .60 inch, .80 by .60 

 inch, .80 by .59 inch, .78 by .59 inch. Other specimens 

 vary but little from these dimensions. Two broods are 

 often reared in the season. , The period of incubation is 

 twelve days. 



VIREO GILVUS. Bonaparte. 

 The Warbling Vireo. 



Muscicapa gilva, Vieillot. Ois., I. (1807) 65. 



Vireo yikus, Nuttall. I. (1832) 309. Aud. Orn. Biog., II. (1834) 114; V. (1839) 

 433. 



Muscicapa melodia, Wilson. Am. Orn., V. (1812) 85. 



DESCRIPTION. 



Third, fourth, and fifth quills nearly equal; second and sixth usually about equal, 

 and about twenty-five one-hundredths of an inch shorter than third ; the exposed 

 portion of spurious quill about one-fourth the third; above greenish-olive; the 

 head and hind neck ashy, the back slightly tinged with the same ; lores dusky ; a 

 white streak from the base of the upper mandible above and a little behind the eye ; 

 beneath the eye whitish ; sides of the head pale yellowish-brown ; beneath white, 

 tinged with very pale yellow on the breast and sides ; no light margins whatever on 

 the outer webs of the wings or tail. 



Length, about five and a half inches; wings nearly three. Spurious primary, 

 one-fourth the length of second. 



This species is a not very common summer inhabitant of 

 New England, arriving and departing at about the same 

 time as the preceding species. It is seldom seen in the 

 deep forests ; and, while usually found about farm-houses 

 and villages, is most commonly seen in localities where there 

 are numbers of the trees of the poplar and ash. In these 

 trees, it inhabits the higher branches ; and is, with the Red- 

 eyed Vireo, equally industrious in its search for insects. Its 

 song is difficult of description : it is, unlike that of our other 

 Yireos, a long-continued, cheerful warble ; and is perhaps 

 best described by saying that it almost exactly resembles 

 the love-song of the Purple Finch. In fact, I have some- 

 times mistaken the song of this bird for that of the other, 

 and only discovered my error after carefully watching the 

 bird in his movements in the tree-tops. 



18 



