Sensitivity of understorey bird species in two different successional stages of the lowland Atlantic Forest, Brazil.

The Atlantic Forest has a high destruction rate and there is little information available on some aspects of the neotropical bird biology. Changes in environment are important factors that affect the resources available to birds. We compared the species sensitivity level of understorey birds in two areas in distinct successional stages (primary and secondary sections). Two 100 ha plots of lowland Atlantic Forest were analysed between August and December 2006. Among 25 bird species recorded, thirteen had lower abundance in secondary forest, two in primary forest, and ten had not clear tendency. According to the criteria used, the percentages for species with low, and medium and high sensitivity to habitat change were 44% and 56%, respectively. The number of species was not associated with the endemism level or foraging strata. Results show the importance of knowing bird species' sensitivity level with regard to habitat modification, and not only forest fragmentation.