Seasonal variation of understory insectivorous birds and arthropods in an area of secondary Atlantic Forest, southeast Brazil

Seasonal variation of understorey insectivorous birds and arthropods was investigated in an area of secondary Atlantic Forest, in southeast of Brazil. Birds were captured with mist nets and arthropods collected on the ground and foliage. A total of 348 captures of 243 individuals belonging to 15 birds species were obtained. Among 3.416 arthropods, 1.782 were collected on the ground and 1.634 on the foliage. There were no significant variation in numbers of captures, individuals and bird species between dry and rainy seasons. The same did not occur with the arthropods, whose seasonal variation was evident in the foliage, more abundant in the dry season, as much as in the ground, more abundant in the rainy season. In this way, although the arthropods number has varied between the seasons, it seems to be a sufficient resource to insectivorous birds feeding necessity through the year. Besides, these birds can present some plasticity, using new foraging tactics in search of this feeding resource.