"We analyze the avian community structure in the El Ocote Reserve in western Chiapas.To compile a species list, we used point count and mist net censuses, continuous observations along available trails and waterways, and recordings of birds singing or calling at dawn and throughout the day. In addition, we observed individuals, groups, and flocks of mixed species in order to characterize patterns of seasonality and abundance, habitat use, trophic structure, social guilds, and food habits. At El Ocote we recorded a total of 334 species of birds from 49 families. This avifauna comprised 223 year-round residents, 14 local or altitudinal migrants, 62 Neotropical (North American) migrants, 27 species with both migratory and resident populations, and 8 intratropical (austral) migrants. We classified habitat use in four categories: 95 species used forest habitats exclusively, 17 were found only in human-altered habitats, 33 used aquatic habitats exclusively, and 24 species were found in open areas or showed no evident habitat affinity. We recorded 202 species with specific food habits. We encountered most species (196) a& solitary individuals or in pairs; 71 species were found attending intra-and interspecific groups, and the remaining 67 species were recorded both solitarily and as members of flocks. In terms of major distributional affinities, we recorded 5 species endemic to Mexico, 70 species endemic to Mesoamerica, 122 Neotropical species, 93 species of North and Central American birds, 41 species distributed widely throughout the Americas, and 6 cosmopolitan species. Local inhabitants may use up to 15 species of birds as a source of food and 27 for ornamental purposes."