FAMILY TURDIDAE 



CATHARUS GRACILIROSTRIS Salvin: Black-billed Nightingale-Thrush, 



Zorzal Piquinegro 



Catharus gracilirostris Salvin, 1865, Proc. Zool. Soc. London, (1864), p. 580. 

 (Volcan de Cartago, Costa Rica.) 



Rather small; bill black. 



Description. — -Length 140-155 mm. Adult (sexes alike), head and 

 neck slate-gray, becoming paler, whiter, on the throat; crown dark 

 brownish gray, lighter, grayer on the forecrown; back of head, hind- 

 neck, back, and rump somewhat reddish brown; wings and tail duller 

 but with brighter edgings; undersurface plain gray changing to white 

 on the abdomen; a broad band of pale dull brown across the upper 

 breast; throat lined narrowly and indistinctly with white; underwing 

 coverts dark gray. 



Immature, upper surface as adult; throat gray; breast, sides, and 

 flanks reddish brown; increasingly buffy on center of belly; abdomen 

 white. 



Found in Chiriqui on the high slopes of the volcano above Boquete, 

 and on the west face; recorded also in eastern Chiriqui on "Cerro 

 Flores" (Cerro Santiago), and in the western end of the Serrania de 

 Tabasara (near boundary between Chiriqui and Bocas del Toro) . The 

 nominate race is found in the mountains of Costa Rica. 



Little is available as yet on the habits of this interesting bird. In the 

 original description of the race accentor, Bangs included the observa- 

 tion by Brown that, like its relatives in the genus, it "is a fine song- 

 ster." Brown's series, 8 adults of both sexes, was collected on the 

 higher slopes of the volcano from about 1500 to 3000 m elevation. 

 Griscom found it in eastern Chiriqui near the western end of the Ser- 

 rania de Tabasara at about 1800 m, where he collected 2 (male and 

 female), in March 1924. With limited comparative material he de- 

 scribed these as a separate race bensoni, which later he found not valid. 

 However, a specimen collected by R. H. Pine on the Chiriqui-Bocas del 

 Toro border 23 km north-northeast of San Felix on June 16, 1980, 

 matches Griscom's original description of bensoni and is easily dis- 

 tinguishable from the series of specimens from western Chiriqui in the 

 Smithsonian collections. 



Eisenmann writes that on the Volcan de Chiriqui massif in the area 

 above Cerro Punta it is the highest ranging nightingale-thrush, usually 

 the commonest above 2100 m on the trail to Boquete. It seems less shy 

 than its allies, often feeding on the ground in cleared patches. On a 

 recently plowed field at about 2250 m, Eisenmann saw one member of 

 a feeding pair chase away one of a pair of the larger C. frantz'n, but the 



