INMADURO - IMMATURE
Tordos Músicos (adultos y/o juveniles) junto a inmaduro de Tordo Pico Corto. Nótese las manchas negras y la falta de la"mascarita" oscura en el cúlmen del Pico Corto.
Grayish Baywings (adult and/or young) together with an immature Screaming Cowbird. Note the dark blotches on the feathers, and the lack of the small dark "face mask" (culmen) of the Cowbird.

Olivos, Buenos Aires - 13-04-2008

INMADURO - IMMATURE
Inmaduro de Tordo Pico Corto siendo alimnentado por adulto de Tordo Músico. La hembra de Tordo Pico Corto ha parasitado el nido del Tordo Músico, dejando allí un huevo para que sea incubado y luego criado por el Músico, junto a los pichones propios. Es conocido que el Pico Corto parasita exclusivamente a los nidos de Músicos, siendo que los pichones de ambos son prácticamente indistinguibles, salvo que le falta la "mascarita" oscura, y cuando ya está un poco más crecido le aparecen manchas negras a medida que el plumaje va tomando los colores del adulto del Pico Corto, totalmente negro.

Brood Parasitism. An immature Screaming Cowbird is being fed by an adult Grayish Baywing, A female Screaming Cowbird has evidently laid an egg in a Baywing's nest, which will incubate and then reaer the chick as it's own, together with its other chicks. It is known that these Cowbirds will only parasitize nests of Baywings, as their young are almost indistinguishable, save for the lack of a dark "face mask", and, as it ages, the appearance dark blotches on it's feathers, as it transitions to the totally black adult plumage of the Screaming Cowbinrd. This breeding strategy is known as "Brood Parasitism".

Olivos, Buenos Aires - 13-04-2008