The expansion of oil palm plantations has caused drastic changes in natural ecosystems and modifications in the vegetation structure, reducing available habitat for native bird species. We studied birds associated with oil palm plantations plots of different palm size classes, in the foothills of the Colombian Orinoquia region, from August 2013 and February 2014. The palm size clases were three: small up to 6 m height; medium up to 10 m; and large up to 15 m; in each plot we counted birds through line transects, and compared their bird composition, richness, and abundance, and described trophic group structure. We recorded a total of 468 individuals, belonging to 44 bird species and 23 families. Gymnomystax mexicanus, Crotophaga ani and Milvago chimachima were the most abundant species, the first tow representing 4.5 % of the abundant species; 25 % had intermediate abundances and 70.4 % were rare in the plantations area. In terms of the abundance of bird species, medium and large palms plots were more similar. Bird community found in plots with large palms had the highest diversity and uniformity (2.63 and 0.8907, respectively), while in those of small palms it was a greater dominance and abundance of individual birds (0.1825 and 252, each one). For the entire plantation, insectivorous and carnivorous birds predominated, and had greater association with small and large palms. Oil palm stands serve as suitable habitats for a small number of widespread bird species, and the height does not seem to be an important factor, that may meaningfully benefit the composition, richness and abundance of bird species associated with the plantations.

Keywords: bird community, agricultural practice, Orinoquia, structural complexity, oil palm, trophic groups.