Seasonality of breeding, moult and fat deposition of birds in subtropical lowlands of southern Brazil

Abstract

The circannual timing of migration, breeding and moult is fundamental for understanding avian life histories. However, much of our knowledge of such processes is derived from studies of bird of temperate regions, with few studies on subtropical or tropical birds. We studied the annual patterns of moult, development of brood patches and fat deposition in a subtropical lowland bird community in southern Brazil and examined the relationship between these patterns and temperature, precipitation and day length. We made 1702 captures of 97 species of birds. Moult and breeding overlap partially in the overall community. Moult of contour feathers occurred year-round, whereas moult of flight feathers occurred from the end of October to the end of May. Migratory species had a shorter moult period than resident species. Breeding peaked in spring (September-December). Fat was deposited seasonally, and the fattest individuals were observed between the end of the moult period and the beginning of breeding. Our data showed that ultimate factors (photoperiod and temperature) influenced vital processes of the life cycles of birds studied. The patterns detected in the seasonality and duration of breeding, moult and fat deposition in this community are generally similar to those of birds in temperate zones.