86 



BIRDS OF THE REPUBLIC OF PANAMA PART 4 



Description. — Length 126-156 mm. Crown and hindneck black in 

 sharp contrast to chestnut-brown of back and upper tail coverts; wings 

 and tail somewhat lighter brown, heavily barred with black; throat, 

 line over the eye, lores, auricular region, and side of jaw white; a nar- 

 row black line below along the side of the jaw. The pattern of color on 

 the upper surface in all of the races is as described above. The under- 

 surface differs widely in the subspecies, from plain chestnut-brown in 

 costaricensis and odicus, to white, barred narrowly with black on the 

 undersurface, in the eastern race schottii (in which there are two dark 

 bars on each feather). 



The range of this species, as here conceived, extends along the Carib- 

 bean slope of Nicaragua, Costa Rica, and Panama (both slopes from 

 Veraguas eastward), western Colombia, and northwestern Eucador. 

 (See Wetmore, Smiths. Misc. Coll., vol. 139, no. 2, 1959, pp. 14-17 for 

 taxonomic review). 



The call note in all is a somewhat guttural chur-r-rk. Song utterances 

 are varied, but all agree in their ringing quality and cadence. The 

 usual variants that may be heard from one male in the course of a few 

 minutes I have written as follows: commonly, chit-i-sit chit-i-sit, re- 

 peated rapidly a dozen times, then perhaps varied to sweety-it sweety-it. 

 This may change to sweety-tu sweety-tu, or sweet-whee-hee sweet- 

 whee-hee. The changes form quite a repertoire, but in final analysis all 

 are rather similar. Males sing alone, but antiphonal duetting by a pair 

 is more common. 



THRYOTHORUS NIGRICAPILLUS COSTARICENSIS (Sharpe) 



Thryophilus costaricensis Sharpe, Cat. Birds Brit. Mus., vol. 6, 1881, p. 217. 

 (Costa Rica = Valley of the Rio San Carlos, Alajuela, Costa Rica.) 



Characters. — Ear coverts, side of jaw, throat, and upper foreneck 

 white; rest of undersurface auburn to hazel; some with sides barred 

 indistinctly with black. 



Measurements. — Males (10 from Bocas del Toro), wing 66.5-71.5 

 (69.6), tail 51.1-56.8 (54.4), culmen from base 20.4-22.4 (21.3), tarsus 

 24.6-26.9 (25.7) mm. 



Females (10 from Bocas del Toro), wing 62.5-67.2 (65.2), tail 46.3- 

 51.3 (49.2), culmen from base 19.7-21.8 (20.7), tarsus 24.1-27.2 

 (25.2) mm. 



Resident. Common in the lowlands of Bocas del Toro, from the Rio 

 Sixaola to the seaward side of the base of the Valiente Peninsula 

 (Cocoplum) . 



