Carriker : List of the Birds of Costa Rica. 741 



515. Planesticus obsoletus (Lawrence). 



Turdus obsoletus Lawrence, Ann. Lye. N. Y., VII, 1862, 470 (Lion Hill, Panama 

 [M'Leannan]); IX, i86"8, 91 (Cervantes, April, 1867 [J. Carmiol]). — Frant- 

 zius, Jour, fur Orn., 1869, 290 (Orosi and Volcan de Poas). — Salvin, Ibis, 

 1869, 312 (critical). — Boucard, P. Z. S., 1878, 50 (Juan Vinas, one speci- 

 men). — Salvin and Godman, Biol. Centr.-Am., Aves, I, 1879, 19 (Costa 

 Rican references). — Seebohm, Cat. Birds Brit. Mus„ V, 1881, 218. 



Merula obsoleta Zeledon, An. Mus. Nac. de C. R., I, 1887, 104 (Zarcero de 

 Alajuela, Siquirris, Naranjo de Cartago). 



Planesticus obsoletus Ridgway, Birds N. and Mid. Amer., IV, 1907, 114 (high- 

 lands of Costa Rica to western Ecuador; — Costa Rica: Cervantes, Orosi, 

 Volcan de Poas, Guapiles, El Zarcero, Tuis). 



Bangs Collection: Juan Vinas (Underwood). 



Carnegie Museum: Guapiles, cT (Carriker & Crawford); Juan Vinas, 

 d\ 2 9 's (Carriker). 



This is one of the rarest, if not the rarest, of the Costa Rican thrushes. 

 It is confined to the Caribbean slope, ranging between 1,000 and 4,000 feet, 

 but seems to be most abundant at about 3,000 feet. It is found only in 

 the heavy forest, and all three of the birds which I secured were taken low 

 down, one being flushed from the ground. 



516. Planesticus tristis leucauchen (Sclater). 



Turdus leucauchen Sclater, P. Z. S., 1858, 447 (Guatemala). — Lawrence, 

 Ann. Lye. N. Y., IX, 1868, 91, part (Navarro [Cooper]). — Frantzius, Jour, 

 fur Orn., 1869, 290, part (Costa Rica). — Boucard, P. Z. S., 1878, 50 (Orosi). 



Planesticus tristis leucauchen Ridgway, Birds N. and Mid. Amer., IV, 1907, 11 1 

 (northern and Central Guatemala to central Costa Rica (Santa Maria)). 



U. S. Nat. Museum: Santa Maria de Dota (Basulto) ; Guayabo (Ridgway 



and Zeledon). 

 Bangs Collection: Tenorio and La Vijagua (Underwood). 

 Carnegie Museum: Volcan de Irazu and Miravalles (Carriker). Three 



skins. 



The distribution of this and the succeeding form is rather a complicated 

 matter, for both birds are found together in several localities. I suppose 

 that this is due to the narrowing of the continental divide, where the two 

 forms, naturally inhabiting each slope, come together in the highlands, 

 but it seems to be always the eastern form which encroaches upon the 

 range of the western. For example, eastern birds are found at Santa 

 Maria de Dota, Miravalles, and Tenorio, all of which localities are decid- 

 edly on the western slope of the continental divide. Some of the birds 

 from Tenorio also show decided signs of intergradation, as if the birds 



