Portal de Periódicos da CAPES

Avifauna da Ilha Queimada Grande, SP: diversidade, estrutura trófica e sazonalidade

2010; Linguagem: Inglês

2639-6459

Arthur Macarrão Montanhini,

Avian ecology and behavior

Little is known about communities on islands, but the Equilibrium Theory of Island Biogeography has been used to interpret the organization of these communities. In Brazil, studies of birds on islands are scarce, which are mainly focused on seabirds and are restrict to list of species. The Queimada Grande Island has been subject of several studies, mainly on Golden Lancehead (Bothrops insularis), an endemic pitviper which feed mainly on birds. However, there are few data on the avifauna of this island. The aim of this study were: (1) describe the richness and trophic structure of bird communities on the Queimada Grande Island, (2) to verify if occurs seasonal variations in richness and abundance of birds in the island, and (3) to compare the difference in the composition and relative abundance of species between island and mainland. We made six field expeditions during five days each one. The sampling was done by transects and count points. Birds were sampled with use of fixed points along a trail that crosses the island in the North-South. A total of 63 species were recorded. The most abundant species was Troglodytes musculus, which is a resident. There were variation in the number of species among the expeditions, and more species were recorded in the dry season. This variation occurs mainly due to migratory species, because these are almost absent in the rainy season, considered the reproductive period of the birds. The guild of omnivores was the most representative in number of species, while insectivores were the most abundant. The Turdus spp. showed more seasonality than other species. The diversity in the continent (Jureia region) was higher than the island. Troglodytes musculus were never recorded as prey of Bothrops insularis, which indicate an ability of the species or this population to avoid the pitviper. On the other hand, other birds as Elaenia chilensis are vulnerably and intensely predated in the period which it remain on the island. This species is the main item in the diet of B. insularis. The Queimada Grande Island has become an important area for birds that are migrating and pass by the island in their way. These birds, in turn, shown to be important for the maintenance of the population of B. insularis in the island.