Characteristics of Feeding Guilds and Variation in Diets of Bird Species of Three Adjacent Tropical Sites

Abstract

We studied feeding guild characteristics of birds in northeastern Venezuela in three adjacent tropical habitats: thorn scrub, thorn woodland, and deciduous forest. We mist-netted and marked birds twice monthly to obtain data on site tenacity. We determined diet by examining regurgitated food samples. Species were assigned to feeding guilds by a cluster analysis based on the proportion of the different food types found in their stomachs. Characteristics of each feeding guild from each habitat were submitted to a principal components analysis. Five parameters clearly distinguished feeding guilds: number of species, proportion of transient individuals, amount of seasonal variation in abundance, mean body mass, and estimated biomass. These parameters also appeared to be related to diet characteristics (food types taken, diet diversity) at the species level. Differences among habitats in food availability led to strong between-site differences in the diet of several species, and, accordingly, in their temporal and spatial patterns of abundance.