CHARACTERISTICS OF FEEDING GUILDS AND VARIATION IN DIETS OF BIRD SPECIES OF 3 ADJACENT TROPICAL SITES

We studied feeding guild characteristics of birds in northeastern Vene zuela 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 regur gitated food samples. Species were assigned to feeding guilds by a clu ster analysis based on the proportion of the different food types foun d in their stomachs. Characteristics of each feeding guild from each h abitat were submitted to a principal components analysis. Five paramet ers clearly distinguished feeding guilds: number of species, proportio n 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 diversi ty) at the species level. Differences among habitats in food availabil ity led to strong between-site differences in the diet of several spec ies, and, accordingly, in their temporal and spatial patterns of abund ance.