546 



BIRDS OF THE REPUBLIC OF PANAMA PART 4 



PHEUCTICUS CHRYSOPEPLUS TIBIALIS Lawrence: Yellow 

 Grosbeak, Piquigrueso Amarillo 



Pheucticus chrysopeplus tibialis Lawrence (ex Baird MS), 1867, Ann. Lyc. Nat. 

 Hist. New York, 8, p. 478. (Cervantes, Costa Rica.) 



Large; bill very thick; wings, upper back, and tail black; wings with 

 white patch at base of primaries; rest of body yellow. 



Description. — Length 182-196 mm. Adult (sexes alike), lores and 

 side of head from lower mandible to below eye blackish; rest of head 

 and undersurface rich yellow, with the feathers of throat and breast 

 brownish except on tips; upper back, black, with feathers sometimes 

 edged yellow; wings and tail black, with white patch at base of pri- 

 maries; lower back through upper tail coverts rich yellow; thighs black; 

 underwing coverts yellow. 



Measurements. — Males (10 from Panama and Costa Rica), wing 

 99.0-114.0 (109.2), tail 70.9-80.8 (76.8), culmen from base 21.9-24.9 

 (23.3), tarsus 20.3-24.1 (22.8) mm. 



Females (10 from Panama and Costa Rica), wing 105.0-112.8 

 (108.0), tail 73.4-82.0 (76.9), culmen from base 23.7-25.2 (24.1), tar- 

 sus 22.7-25.0 (24.2) mm. 



Resident. Uncommon in the highlands of Chiriqui, Bocas del Toro, 

 and Veraguas. W. W. Brown, Jr., collected 3 males at Boquete and 

 the Caribbean slope of Volcan de Chiriqui between 1500 and 1680 m 

 (Bangs, Proc. New England Zool. Club, vol. 3, 1902, p. 68), Monniche 

 found it on the Volcan de Chiriqui between 1560 and 2040 m (Blake, 

 Fieldiana: Zool., vol. 36, no. 5, 1958, p. 569), and Frank Hartman col- 

 lected a female at 2100 m on Cerro Copete, near Boquete. Ridgely (in 

 litt.) found this species more numerous at Fortuna, Chiriqui, during 

 February-March 1976 than anywhere else in his experience; here it 

 ranged down to 900 m, and was usually seen singly, less often in pairs. 

 In Bocas del Toro, Kennard found it on the Boquete Trail at 420 m 

 (Kennard and Peters, Proc. Boston Soc. Nat. Hist., vol. 38, 1928, p. 

 460) . Arce collected it in Veraguas at Chitra, Calovevora, and Calobre 

 (Salvin and Godman, Biol. Centr.-Amer., Aves, vol. 1, pt. 34, 1884, 

 p. 336) . Skutch and Pujals (Ridgely in litt.) saw one above Santa Fe, 

 Veraguas, on March 28, 1974. This race also occurs in Costa Rica. 

 Other races, which have been treated as as many as three species, are 

 found from northwestern Mexico to southern Peru. 



Hellmayr (Field Mus. Nat. Hist., Zool. Ser., vol. 13, pt. 11, 1938, 

 pp. 79-80) considered tibialis 'nothing but a strongly marked race 

 of P. chrysopeplus, as is indicated by certain individual variants," 

 whereas Blake (op. cit., p. 570) felt that tibialis has evolved "beyond 



