Breeding biology and natural history of the Austral Thrush (Turdus falcklandii) in central Chile

Abstract

Some natural history aspects and breeding biology of the species was studied in central Chile, near Melipilla. Its habitat was closely attached to humid places; man-made habitat modifications most likely favored the Austral Thrush, extending its breeding season to 5½ and perhaps up to 6 months. Most (61%) of the nests were found in non-native but dense vegetation. The nest height on average were at about 2 m above the ground (n=56). The nests were cup shaped and made with leaves, mosses dry grasses with an internal layer of mud and lined with very fine grasses. Further south in the country, nests can be found in the ground and also built with no layer of mud but instead a compact layer of mosses. The clutch size varied between 2 and 3 eggs, although, 55.4% of the nests had a clutch size of 2 (n=103). The incubation period was 14.1 days ranging between 14 and 15 days. The nestlings fledged between 9½ to 13 days. The T_10-90 period was of 7 days and the growth constant was K= 0.628. The body mass at hatching was 6.5g and the maximum mass acquired by the nestlings was 72g. On the eggs, followed in more detail (n=71), 14% were depredated. Most mortality occurred on the early nestling stages between ages 1 and 6 days, 44.3% of the hatched eggs were depredated. The total breeding success was 41%.