FAMILY THRAUPIDAE 



461 



CHLOROTHRAUPIS OLIVACEA (Cassin): Lemon-browed Tanager, 

 Frutero Cejiamarillo 



Orthogonys olivaceus Cassin, 1860, Proc. Acad. Nat. Sci. Philadelphia, p. 140. 

 (Rio Truando, northwestern Colombia.) 



Medium size; entirely yellowish green except for yellow lores, ring 

 around eye, and throat. 



Description. — Length 150-164 mm. Adult male, lores and ring- 

 around eye bright yellow; entire upper surface, including wings and 

 tail, olive-green; chin and throat bright yellow, finely streaked at sides 

 with green; undertail coverts yellow; rest of undersurface yellowish 

 green, with wash of yellow in center of belly; bend of wing yellow; 

 underwing coverts yellow and green. 



Adult female, like male, but slightly lighter, more yellow, on under- 

 surface. 



Measurements. — Males (10 from Darien), wing 85.6-93.3 (90.6), 

 tail 61.2-68.2 (64.5), oilmen from base 18.8-21.3 (20.0), tarsus 21.3- 

 23.6 (22.1) mm. 



Females (10 from Darien and Colombia), wing 82.1-90.6 (86.4), 

 tail 55.5-69.0 (62.5), oilmen from base 18.0-21.2 (20.3), tarsus 20.1- 

 22.8 (21.4) mm. 



Resident. Fairly common in the lowlands and foothills of eastern 

 Darien and, beyond Panama, in Colombia and northwestern Ecuador. 

 It has been collected at Cerro Sapo (900 m) (Bond and de Schauensee, 

 Acad. Nat. Sci. Philadelphia, Mon. no. 6, 1944, p. 44) and by E. A. 

 Goldman at Cana between 600 and 1050 m. I have found it at Jaque, 

 Rio Jaque, and at 550 m at Cana. Ridgely (1976, p. 323) also lists it 

 for Cerro Quia and Cituro. 



In habits and vocalizations, this species is very similar to Chloro- 

 thraupis carmioli. When I have encountered them, they were ranging 

 low down in undergrowth, giving low chattering calls. Goldman noted 

 the contents of the stomachs of 2 he collected at Cana: 1 held bits of 

 caterpillar 60%, two fragmentary ants 30%; bits of a weevil 5%, 

 other Coleoptera 5%; the other contained a small scarabaeid 10%, bits 

 of a rhyncophoran 15%, a wasp 10%, more than 5 ants 55%, 7 seeds 

 of Solanum sp. 10%, three other minute seeds not determined. Three 

 collected by Burton (Bull. Brit. Orn. Club, 1975, p. 86) at Cerro Pirre 

 weighed from 36 to 41 g. In July 1975, Ridgely {in litt.) found them 

 one of the most numerous of forest interior birds at Cerro Quia; he saw 

 them in groups of 2-6 individuals. On three occasions Ridgely saw 

 fledged young being fed. 



