Diet breadth and overlap in three sympatric aerial insectivorous birds at the same location

Abstract

Capsule We found significant differences in the composition and diversity of diet among House Martins, Barn Swallows and Swifts breeding in the same village in Poland.Aims To evaluate the character and extent of diversity, specialization and overlap of diet between trophically similar nestlings of three species of aerial feeding birds breeding at the same location and differing considerably in foraging height.Methods Diet was determined based on faecal analysis. Differences in composition and diversity of diet and food niche overlap were assessed through multivariate analysis of variance (manova), Shannon Diversity Index and the Pianka index. Diet specialization was measured by application of the Berger–Parker index of dominance.Results manova indicated significant differences in diet composition among all three species. House Martins showed the most diverse diet, Swallows were intermediate and Swifts least diverse. Average body mass of all prey found in the diet of Swifts was nearly three times smaller than in Swallows and two times smaller than in House Martins.Conclusion Our findings show that these three species consume the same types of insect prey, but they take different proportions, and hence biomass, of the major prey groups. House Martins had the widest niche and greatest overlap.