Biologia e sucesso reprodutivo de mimus saturninus (aves: mimidae) no cerrado

AUTOR(ES)
DATA DE PUBLICAÇÃO

2009

RESUMO

The Chalk-browed Mockingbird, Mimus saturninus (Mimidae) is a very common bird in cerrados, grasslands, and pasturelands with scattered trees or shrubs, also occurring in urban environments. Here I studied aspects of its breeding biology and success in a natural cerrado. Data was collected at Estação Ecológica de Águas Emendadas (ESECAE) from 2003 to 2008. I monitored 64 nests of which 55 had a known fate. I used 45 nests for the reproductive success and nest survival analyses. Most nests (50%) were found at open cerrado. Incubation was asynchronic and nesting lasted from August to December. Nests were an open-cup built with twigs usually on a Davilla elliptica (Dilleniaceae) shrub. Mean nest height above the ground was 1.3 0.6 m. Clutch size was invariably of three, but ranging from one to six eggs. Both the incubation and the nestling period lasted 14 0.3 days. Only one nest was parasited by the Shiny Cowbird, Molothrus bonariensis. The apparent success, the success of eggs and the Mayfield success were 54.5, 40.5 and 54.6 %, respectively. Predation was the main cause of nest failure, accounting for 88% of loses. Among the predated nests, 86.4% were lost during the nestling phase and only 13.6% were lost during the incubation phase. Nestling infestation by botflies was common but did not cause the death of nestlings. Nest survival rates, modeled by the logistic exposure method, showed that they could vary according to nest age and clutch size. Larger clutch sizes had higher survival rates than smaller clutch sizes. Nests at the end of incubation phase had a decrease in survival, had the lowest success in the first days of the nestling phase and increased again at the end of the nestling phase. Nests daily survival rates were not affected by vegetation type or by time of the season.

ASSUNTO(S)

cooperative breeding life history história de vida sobrevivência de ninhos nest survival sabiá-do-campo chalk-browed mockingbird program mark ciencias biologicas reprodução cooperativa programa mark

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