FAMILY VIREONIDAE 



225 



flexible in its choice of habitat and food. It feeds extensively on in- 

 sects, but at Isla Parida, Chiriqui, I took 2 on February 5, 1963, that 

 had eaten small drupes. The specimen collected by Morton at Gatun 

 Dam had in its stomach "red arils, green Miconia fruit; no insects," 

 while that taken at Albrook had "small beetles of several species and 

 one small buprestid" (data on labels in American Museum of Natural 

 History). On March 20, 1975, Morton and Eisenmann noted 2 in a 

 Burs era tree with a variety of northern wood warblers in the light 

 woodland of Farfan Road, southwestern Canal Zone. 



Buskirk et al. (Auk, 1972, p. 619), when studying mixed species 

 flocks near Cerro Punta, Chiriqui found that Philadelphia Vireos were 

 present in at least 26 percent of the flocks they observed; the vireos 

 were "joiners," but did not follow the flock from place to place. At 

 the same locality Leek (Bird-Banding, 1975, p. 202) banded and 

 weighed Philadelphia Vireos in 1968; he found that the average weight 

 of 12 taken in March was 11.4 g and the next month 5 averaged 12 g. 

 A bird that I took at Pedasi, Los Santos, on March 17, 1957, was not at 

 all fat. 



Ridgely (in litt.) observed a Philadelphia Vireo on Barro Colorado 

 Island (March 13, 1979) with an antwren flock. He notes that in many 

 areas this species seems to prefer coffee groves above all other habitats, 

 especially where there are trees shading the coffee and where rank 

 vegetation has grown up around the coffee bushes. 



VIREO GILVUS (Vieillot): Warbling Vireo, Vireo de Capucha Chocolate 



Muscicapa gilva Vieillot, 1808, Hist. Nat. Ois. Amer. ; September 1, (1807), p. 65, 

 pi. 34. (New York State.) 



Small; crown brown; rest of upper surface olive-green; superciliary 

 white; throat and breast white; rest of undersurface pale yellow. 



Description. — Length 107-121 mm. Adult (sexes alike), crown 

 olive-brown; rest of upper surface grayish olive to brownish olive- 

 green, superciliary white; dusky brown postocular streak and loral 

 spot; facial area, throat, upper chest grayish, and white; rest of under- 

 surface, edge of wing, and underwing coverts pale yellow or whitish. 



Vireo gilvus, the Warbling Vireo of North America and Mexico, in- 

 cludes other forms through Central America and as far south as Bo- 

 livia and southeastern Peru. Blake (Checklist Birds World, 1968, p. 

 127-129) distinguishes 17 forms, all of which he puts in V. gilvus. 

 Some consider the races south of Oaxaca, Mexico, distinct enough 

 from northern gilvus to merit specific status under the name leucophrys, 

 while others believe the races breeding from southern Mexico to Nica- 



