Reversed Sexual Dimorphism and Differential Prey Delivery in Barn Owls (Tyto alba)

Abstract

We studied reversed sexual dimorphism (RSD) and foraging behavior of Barn Owls (Tyto alba). Bill length, tarsus length, wing chord, tail length, and mass of Barn Owls showed RSD. Mass of the prey items brought by the males was significantly less than that brought by females, which may be attributed to the positive correlation between size of the owl and prey mass. However, male owls had a significantly higher frequency of visits with prey than did females. There was relatively little overlap in the species and mass of prey captured by males and females, suggesting that food-niche partitioning between the sexes may exist, possibly to reduce intersexual food competition. Further, because these differences were also observed between the male and female owls within each pair, our findings support reproductive role division as a possible explanation for RSD in Barn Owls.