Progressive greying in the groove-billed ani (Crotophaga sulcirostris) in Costa Rica.

Plumage color aberrations are common in birds, but often they are difficult or even impossible to identify properly. The pigmentary abnormality with the greatest prevalence among birds is progressive greying, although it is often confused with leucism and albinism. Here we report the first case of progressive greying for the groove-billed ani (Crotophaga sulcirostris) based on an individual observed in Costa Rica. This individual had white feathers in various parts of the body, while the rest of the body maintained its black feathers. The individual was observed on a live fence of a pastureland in the Tropical Moist Forest (perhumid transition) on the pacific slope of central Costa Rica. [ABSTRACT FROM AUTHOR]