CONICET | Buscador de Institutos y Recursos Humanos

Studies of Andean avifaunas at the mesoscale (1000s km2) are scarce, but they may prove critical for understanding community structure and for conservation planning. We studied species diversity, composition and abundance of bird communities in premontane forests of northwestern Argentina (c. 2000 km2). We measured changes between breeding and non-breeding seasons, focusing on migrants and trophic guilds, and we compared flat and foothill areas. Twelve bird communities were sampled using point counts, mist nets, and line transects. More species were recorded during the breeding than the nonbreeding season, in part due to the arrival of migrants, but the abundance of birds did not differ between seasons. We registered more individuals and species of migratory birds during the breeding season. Latitudinal and elevational migrants characterized breeding and non-breeding assemblages, respectively. We found no significant differences in bird species richness, composition or abundance in relation to forest type (i.e., flat vs foothill), in part due to the patchy distributions of birds across the entire study area. Different feeding guilds characterized each season: insectivorous and granivorous species that foraged in or above the canopy were common during the breeding period, while frugivores-insectivores and insectivores that feed at all forest strata characterized the non-breeding period. Out of 112 species registered, at least 10 are of conservation concern for Argentina, 14 are uncommon in the Neotropics, and 31 are migrants, highlighting the role of premontane forests for regional conservation. Most (c. 75%) premontane forests have already disappeared or are largely degraded. This situation calls for a rapid shift in regional policies, only possible if government, landowners, NGOs and academic institutions can share the common goal of habitat protection.

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