We analyzed the avifauna from four areas of the Rio Doce basin (the municipal districts of Nova Era [NE], Antônio Dias [AD], Caratinga [BSC], and Marliéria [RDSP]) located in eastern Minas Gerais state. Based on captures with mist nets, 75 bird species belonging to 15 families were inventoried; however, the species composition varied greatly among the study areas. Fifty species and 231 of the 466 individuals recorded during this study were captured at NE. In the AD area, 33 species and 132 individuals were captured. The other two areas, BSC and RDSP, contributed only 103 captures and 22 species. By analyzing species composition as a function of altitude of the study areas, it was verified that a variation of 500 m altitude was sufficient in determining the difference in existing bird communities. Formicariidae species, such as Drymophila squamata, Thamnophilus punctatus, and Conopophaga melanops, were captured exclusively in the BSC and RDSP areas, located below the 500 m altitude limit while their congeners (D. ochropyga, T. caerulescens, and C. lineata) were found exclusively in the highest areas (NE and AD). Significant seasonal variations in the species composition were observed (Green's test: Q = 12.79 in NE, 12.84 in AD, 12.4 in BSC, and 20.68 in RDSP; P < 0.05), and we believe that such variations could be associated with seasonal movements between the highest and lowest areas of the Rio Doce basin. As such, the impacts of fragmentation to the Atlantic Forest along this stretch of the Rio Doce basin may have affected the natural dynamics of avian movements. The destruction of > 90 percent of the original Atlantic Forest vegetation cover already may have seriously compromised the population viabilities of birds endemic to this area.