FAMILY FRINGILLIDAE 



587 



green on undersurface; wings and tail black; bend of wing and thighs 

 yellow; underwing coverts blackish gray. 

 Immature, thighs dark gray. 



A male collected at Volcan de Chiriqui, Chiriqui, on March 2, 1965, 

 had the iris pale dull reddish brown; bill black; tarsus and toes fuscous- 

 brown; claws black. 



Measurements. — Males (10 from Chiriqui), wing 78.0-89.9 (85.8), 

 tail 81.8-95.2 (89.8), oilmen from base 14.3-17.7 (15.9), tarsus 26.0- 

 27.9 (26.9) mm. 



Females (10 from Chiriqui), wing 75.5-85.0 (80.2), tail 77.5-89.0 

 (83.7), culmen from base 15.5-17.2 (16.1), tarsus 24.0-26.5 (25.5) 

 mm. 



Resident. Very common in the highlands of western Chiriqui and 

 adjacent Costa Rica. In Panama, it has been collected on Cerro Punta, 

 near Boquete (1380-2340 m), and Volcan de Chiriqui (1590-3060 m) 

 (Blake, Fieldiana: Zool., vol. 36, no. 5, 1958, p. 572). 



The Yellow-thighed Finch is a versatile species that inhabits the un- 

 dergrowth of forests and clearings, and forages from the ground to the 

 treetops. On the ground it searches for insects and spiders among the 

 leaves and in grass at the edge of clearings. In shrubbery it feeds on 

 berries and the nectar of tubular flowers, and high in trees it moves 

 actively through the foliage like a wood warbler. These finches are 

 usually found in pairs, sometimes with other small birds like brush- 

 finches and warblers. Skutch (Publ. Nutt. Orn. Club, no. 7, 1967, pp. 

 188-189) describes two very different songs, "a long-continued, rapid 

 flow of somewhat tinkling notes, all very much alike, with no definite 

 phrasing" given throughout the year, and "short, rapid, breezy little 

 ditties delivered in a peculiar high, dry tone" repeated over and over, 

 chiefly at dawn during March, April, and May. Skutch believes the 

 first song is a form of greeting given by both members of a pair after a 

 separation, while the second song is delivered only by the male. 



Skutch found this species nesting in Costa Rica during March, April, 

 and May. The nests were from 1 to 3 m above the ground, concealed 

 in thick grass or foliage of a tree bough. They were bulky open cups 

 made of straws and grass blades, with a thick, soft lining of fine vege- 

 table fibers. Sometimes bamboo leaves are used. Two eggs form a 

 clutch; they are "white or faintly tinged with blue, with a heavy crown 

 of mingled brown and lilac speckles thinly scattered over the remaining 

 surface. The eggs of two sets measured 24.6 by 17.9 and 24.6 by 18.3; 

 25.4 by 18.3 and 24.6 by 18.3 mm." Skutch could not determine the 

 incubation period, but young remain in the nest until 12 days old. 



