Behavioral response of resident Jamaican birds to dry season food supplementation

We used plot-level manipulations and analyses to test the effects of food availability on the behavior and condition of resident dry-forest birds in Jamaica. Two control plots were monitored in each of 2 yr. Food was Supplemented on five plots over 2 yr with piles of cut oranges distributed around plots, which served as a direct source of carbobydrates and water, and an indirect Source of ground arthropods due to increased above-ground activity. We reduced ants on five plots over 2 yr; however, We found no difference in total ground arthropod biomass between control and reduction treatments, so we pooled these plots For analysis. We selected nine focal resident bird species for study of relative abundance, body condition, and breeding condition. Birds were sampled prior to, and 5 to 6 weeks after the initiation of treatments. Seven of nine species had higher relative abundance following food supplementation. Three species were recaptured more frequently in supplementation plots than in control plots. These abundance and persistence responses did not Cause any changes in body condition. In one species, Bananaquit (Coereba flaveola), food supplementation resulted in higher concentrations of individuals in breeding condition. These results demonstrated Functional response to dry-season food availability and suggest a limiting mechanism. This Study helps explain mechanisms by which bird populations respond to resource availibility, and is the first Successful plot-level food supplementation experiment for tropical forest birds.