Spatial Variation in the Diet of the Barn Owl Tyto alba in the Caribbean

On Bonaire we assessed Bam Owl Tyto alba diets at four discrete sites. The 233 fresh pellets contained 755 identifiable prey items from four taxonomic orders. Average prey diversity differed two- to threefold between sites. Dietary composition showed large spatial variations between sites, from predominantly insectivorous to avian. Between-island variation was assessed by comparing the dietary composition of populations of Barn Owls on nine islands throughout the Caribbean region as reported in the literature. On 8/9 islands mammals (mainly rodents and bats) formed the main diet. On half of the islands about a fifth or more of the prey comprised birds. Reptiles and/or insects were eaten on 5/9 islands, but rarely dominated the diet. These large within-island dietary differences reflect differential prey availabilities in the Caribbean, possibly enhanced locally by specialisation.