300 BIRDS OF THE REPUBLIC OF PANAMA PART 4 



Adult female, like male, but gray on crown less extensive, rest of up- 

 per surface slightly browner than male; black area less intense, and 

 yellow undersurface paler. 



Measurements. — Males (8 from Chiriqui and Costa Rica), wing 

 53.5-57.0 (54.8), tail 51.7-61.1 (56.3), culmen from base 11.8-13.2 

 (12.5), tarsus 20.4-23.2 (21.7) mm. 



Females (5 from Chiriqui and Costa Rica), wing 50.0-57.7 (53.3), 

 tail 54.9-62.1 (57.7), culmen from base 11.7-13.2 (12.5), tarsus 21.0- 

 22.8 (21.8) mm. 



Resident. Uncommon and local in the foothills and highlands of 

 western Chiriqui from 690 to 2250 m (Ridgely, 1976, p. 301), and 

 west to the Terraba Valley in southwestern Costa Rica. Other races 

 are found from extreme southern Texas through Middle America. 

 This yellowthroat inhabits overgrown and abandoned pastures and 

 brushy fields. Monniche collected specimens at Lerida and Quiel on 

 the Volcan de Chiriqui (Blake, Fieldiana: Zool., vol. 36, no. 5, 1958, 

 p. 560) and W. W. Brown, Jr., collected it also at Boquete (Bangs, 

 Proc. New England Zool. Club, vol. 3, 1902, p. 61). The only place I 

 found this species was at El Salto (1200 m), near Boquete, where on 

 March 17 and 18, 1960, I collected a male and female in a field of 

 bracken and grass. The song, which is sometimes delivered from an 

 exposed perch as high as a tree branch or a wire, is "somewhat similar 

 to semiflava and has a number of undistinctive vireo-like phrases strung 

 together. It is not so long as that of semiflava, does not ramble up and 

 down so markedly, and lacks a slur at the end although one may be 

 thrown in elsewhere" (Slud, Bull. Amer. Mus. Nat. Hist., vol. 128, 

 1964, p. 330) . This species also has at least a half dozen calls. Rowley 

 (Condor, 1962, p. 262) found the nest of the nominate race near 

 Cuernavaca, Mexico. It was in dry grass bordering a cleared field and 

 was made entirely of dried grasses; it contained 3 eggs. 



Eisenmann (Auk, 1962, pp. 265-267) reviews all characters of this 

 species, formerly placed in the monotypic genus Chaemethlypis, and 

 concludes that it is not allied to Icteria but is properly placed in the 

 genus Geothlypis, the only distinction between it and other members of 

 the genus being the larger bill. It is "simply a yellowthroat of the drier, 

 more sterile uplands, as distinct from the marshes or borders of wet 

 places preferred by other yellowthroats. The drier niche, with the con- 

 sequent difference in diet, doubtless accounts for the heavier bill, which 

 is presumably useful in feeding on harder-bodied or larger insects (and 

 possibly on seeds) than are normally taken by yellowthroats of water 



