The avifauna of the region of the Serra da Guia, in the municipalities of Poco Redondo (Sergipe) and Pedro Alexandre (Bahia) was surveyed between October, 2008, and September, 2009. Data were collected at two locations, representing the semi-arid caatinga, and a humid highland forest enclave (brejo de altitude). During each month of the study period, specimens were captured during three sessions in each of these habitats using mist-nets (100 m), with complementary data being collected in active searches. A total of 587 individuals representing 80 species were captured in the caatinga, while 392 specimens from 64 species were netted in the humid forest. Overall, the occurrence of a total of 139 species was confirmed, although at least 171 species are estimated to occur in the region. A distinct pattern of activity was observed between the two habitats, with the peak in activity (captures) occurring between 05:00 h and 08:00 h in the caatinga, and between 08:00 h and 10:00 h in the humid forest. A secondary peak at 17:00-18:00 h was recorded at both sites. Sixteen species were endemic to Brazil, of which, four are endemic to the caatinga. Seven species are included in the IUCN red list. The trophic structure of the local bird community was dominated by insectivore and omnivores in both habitats. While there are no conservation units within the study area, the humid forest enclave represents a unique system, which requires urgent protection.