Effects of floristic and structural features of shade agroforestry plantations on the migratory bird community in Colombia

Abstract

How habitat mediates the distribution and habitat selection of migratory birds that winter in agroforestry systems is still poorly known. In this research, we evaluated how different habitat characteristics in shade agroforestry plantations influenced the richness and abundance of the overwintering migratory bird community. We examined migratory bird diversity and habitat structure in nine farms with coffee agroforestry systems with different shading regimes during two wintering seasons in southwestern Antioquia Department, Colombia. 15.9 ± 3.69 species of migratory birds were found on the 9 farms (range 11–21 species). While we found little support for a strong association between richness of migratory birds and habitat variables, abundance of migratory birds was best explained by the combined effect of habitat characteristics. Particularly, the total number of individuals of migratory birds was positively related to structural attributes such as shrub density, canopy cover, tree density and diameter at breast height, suggesting that a denser and closed shading system might be beneficial for migratory birds, which may both increase the horizontal and vertical complexity of the agroforestry system and the variety of food resources for birds. Our surveys showed additional evidence that shaded systems can provide overwinter habitat to Neotropical migrant birds in the Colombian Andes. Moreover, we suggest that migratory birds can benefit by managing structurally and floristically diverse agroforestry and silvopastoral systems.