A twelve-month field study of the West African Thrush Turdus pelios (Passeriformes: Muscicapidae): Part 2: annual cycles

ABSTRACT

In Africa, birds inhabiting forested regions are less seasonal in their activities than those from open areas. In order to study annual cycles in forest regions of South western Nigeria, West African Thrushes (Turdus pelios ) were mist-netted and banded during the last two weeks of each month. The nest is a cup-shaped structure built out of grasses, herbs, weeds, roots and earth laid out in a clockwise manner. Only the nesting tree and feeding sites were defended during the breeding period. The clutch size was 2.69 ±0.20 eggs with a mean incubation period of 14.11 ±0.26 days. The mean nestling period was 15 ±1.00 days. The nestlings were fed on a variety of plant and animal matter, of which grass seeds and insects were predominant. Moult was found to be protracted with a population moult period of 194 days and a much shorter individual moult period. Moult and breeding periods were spread out moult period dovetailed into the breeding period. The birds were found to gain weight during the period but they attained their maximum weight in August after the moult period. The lowest weight was recorded in February, during the peak of the dry season, when food availability was lower

RESUMEN

El nido del tordo africano occidental es una estructura en forma de copa construida con pastos, hierbas, malezas, raíces y tierra, proyectado en el sentido de las manecillas del reloj. Solamente el árbol con el nido y los sitios de alimentación son defendidos durante la crianza. El tamaño de la nidada fue 2.69 ± 0.20 huevos con un periodo de incubación de 14.11 ± 0.26 días. El periodo promedio de cría fue de 15 ± 1.00 días. Los polluelos fueron alimentados con una variedad de material animal y vegetal, predominando las semillas de pasto y los insectos. La muda del plumaje alar es prolongada, con un período poblacional de muda de 194 días y un periodo individual mucho menor. La muda y crianza son tan prolongados que se empalman con el periodo de crianza. Las aves ganaron peso durante el periodo pero alcanzaron su peso máximo en agosto, después del periodo de muda. El peso más bajo fue el de febrero, lo que coincide con el pico de la estación seca, cuando los recursos alimenticios son escasos