BLUE-HEADED VIREO 301 



gray; in shadow, or at a distance, it appears a dark slate-color. But 

 the pure white eye ring and the white stripe in front of the eye, the 

 "spectacles," are conspicuous at considerable distance. On the nest 

 the gleaming white throat, in sharp contrast with the dark head 

 markings, shows plainly above the rim of the nest. The two white 

 wing bars, which the red-eyed vireo lacks, the pure white breast, and 

 the yellow sides are good field marks. 



Enemies. — Undoubtedly some eggs and young are destroyed by 

 predators, such as blue jays, crows, chipmunks, squirrels, and perhaps 

 snakes, as many rifled nests have been found. Based on my experi- 

 ence, mentioned above. Cooper's hawks do not molest them even when 

 nesting nearby; and Mr. Forbush (1929) says that the vireos also 

 nest in the same woods with goshawks and red-tailed and sharp- 

 shinned hawks. 



The blue-headed vireo is a common victim of the cowbird ; if the 

 cowbird's Qgg is laid before the vireo has laid any of her own, the 

 vireo may cover it up and lay her eggs in the upper story ; Dr. Fried- 

 mann (1929) says that the bluehead does this more often than the 

 other vireos; but, after any of her own eggs are laid, she will not 

 cover them. Unless the alien eggs are removed, the poor vireos will 

 probably raise only young cowbirds. 



Harold S. Peters (1936), in his list of external parasites, mentions 

 cnly one tick {Haemaphysalis leforis-palustris Packard) found on 

 this vireo. 



Winter.— Krihuv T. Wayne (1910) says that "this vireo winters 

 abundantly in the great swamps which are in close proximity to our 

 [South Carolina] coast. That it is a common bird in the months of 

 December, January, and February there is no question, for I have 

 often seen and counted as many as ten individuals in the course of a 

 few hours. On mild days in winter the birds sing with some vigor, 

 but it is not until March that the full volume of song is heard." 



Arthur H. Howell (1932) says that, in Florida "in winter it is 

 often found in low, swampy thickets." Dickey and van Rossem 

 (1938) say of the blue-headed vireo in El Salvador: "The center of 

 abundance of this very common winter visitant was along the upper 

 edge of the Arid Lower Tropical Zone, in other words in the coffee 

 districts at about 3,500 altitude. In numbers it compared favorably 

 with the warbling and Philadelphia vireos, but of course was much 

 more in evidence. The smaller species are ordinarily silent or at least 

 do not sing, but the familiar song of solitarious may be heard through- 

 out the winter. This species, far more than the warbling and Phila- 

 delphia vireos, was likely to accompany the composite flocks of visit- 

 ing warblers." 



Mr. Skutch writes to me : "The blue-headed vireo winters in north- 



