BLACK- WHISKERED VIREO 319 



wings (except lesser coverts) and tail as in adults, but greater wing- 

 coverts indistinctly tipped, as well as edged, with pale yellow ; super- 

 ciliary stripe and sides of head bnffy whitish, partly separated by a 

 dusky loral and postocnlar mark; malar region, chin, and throat paler 

 buffy white or vinaceons white; rest of under parts white, the sides, 

 flanks, and under tail-coverts tinged with sulphur yellow." 



The small amount of pertinent material available indicates that 

 subsequent molts and plumages parallel those of the closely related 

 red-eyed vireo, with a partial postjuvenal molt, involving the contour 

 plumage and the lesser wing coverts in young birds, and a complete 

 postnuptial molt in adults. 



Food. — Dr. Edward A. Chapin's (1925) report on the food of the 

 black-whiskered vireo was based on the examination of only four 

 stomachs, collected in Florida in May and June. He writes : 



Of the entire food, 87.5 percent was of animal origin. By far tlie largest single 

 item was spiders, 39.25 percent of the whole ; in one stomach were the remains 

 of 10 individuals of one kind ( Tctrcumdtha ) . Caterpillars and eggs of some moth 

 or butterfly made up 14.25 percent of the food. In one stomach were 10 small 

 earwigs (Forficulidae), which represented about 10 percent of the animal food. 

 Miscellaneous beetles, including weevils from one stomach, made up 18.25 percent, 

 and the remaining 5.75 percent was composed of wasps or bees and assassin bugs 

 (Reduviidae). 



The vegetable food, 12.5 percent of the total, was composed of fruit of barberry 

 (Berhcris) and of ragweed (Ambrosia) , found in three of the four stomachs. 



The number of stomachs examined was far too small to give an 

 adequate picture of the food of this bird, especially as they were col- 

 lected between May 21 and June 7. The examination of 84 stomachs 

 of the typical race, taken in Puerto Rico, "show that the bird is de- 

 cidedly frugivorous, inasmuch as wild fruits or berries were detected 

 in 80 of the 84 stomachs examined and amounted to 57.82 percent." 

 Probably birds collected in Florida or Cuba later in the season would 

 show a larger percentage of vegetable food. 



Harold H. Bailey (1925) says that in Florida "they feed in the 

 hammocks from the lovv-er bushes to the highest branches, on small 

 spiders, caterpillars, flies, mosquitoes, and most of the small varieties 

 of insects." 



Behavior. — Mr. Maynard (1896) writes: 



In habit this species is quite peculiar in some ways. They keep well in the tops 

 of the trees, seldom, if ever, feeding in the low scrub. They are exceedingly 

 agile in movement, having a peculiar briskness of action which is quite unvireo- 

 like. They are, almost without exception, shy, and when they perceive an in- 

 truder, which they are apt to do very quickly, as they are ever on the alert, they 

 erect the feathers of the head, droop the wings, spread the tail and utter a series 

 of scolding notes quite unlike those of any other Vireo I ever heard. Then after 

 flying restlessly from bough to bough for a moment or two, they utter a shrill 

 scream of anger and off they go, generally flying several hundred yards in a 

 straight line before alighting again. Even while feeding by themselves, they 



