Comparison of food habits and prey selection of the white-tailed kite, Elanus leucurus, between natural and disturbed areas in central Argentina

摘要

We studied the food habits of white-tailed kites (Elanus leucurus, Accipitridae) in central Argentina during austral spring and summer (November to March) and compared prey captured in two different habitat types. Diet was determined by analysing pellets and prey remains collected under nests and roost sites. During the same period small mammals were trapped using pit-fall traps in Parque Lurci reserve with the aim of assessing prey selection by kites. In Parque Luro reserve (semiarid forest), tuco-tucos (Ctenomys sp., Rodentia) were the main prey in the white-tailed kite diet, accounting for 75% of the items and 91% of biomass. In agricultural fields, however, there was not a single main prey species, as measured either by number of prey items or by biomass, Calomys sp. (43%) and Akodon azarae (22%) being the main prey in this habitat. The analysis of prey availability in the Parque Luro reserve showed that tuco-tucos are a seasonally available prey, only captured in spring and summer. During these seasons, the consumption of tuco-tucos by white-tailed kites was disproportionately higher than the occurrence of tuco-tucos, indicating a preference for this species by kites. These results suggest that other prey attributes, such as conspicuousness and social behavior, could be key factors in prey selection by white-tailed kites.