Abstract

In 2004-05, we evaluated seasonal variation in the diet of White-tailed Kites in a suburban area of Conceptión, southern Chile. Kites' diet was determined based on pellets (N = 209) and consisted of rodents, insects and birds (95.6%, 13.8% and 0.6% of all consumed individual prey [N= 343]). Olivaceous field mice (Abrothrix olivaceus) and long-haired mice (A. longipilis) were the most common prey (47.5% and 32.4% of all prey by frequency, respectively; 40.3% and 38.9% by biomass, respectively). Rodents were important in the diet in all seasons (frequency = 88.6-100%, biomass = 98.8-100%), and the ranking of rodent prey species in the diet was virtually the same for all seasons (x2 = 4.6, P >0.05). The geometric mean weight of vertebrate prey was also similar among seasons (27.0-28.6 g). The frequency of rodent prey species in the pellets was positively correlated to rodent prey abundance in the environment, as measured using live-trapping surveys (r s = 0.83, P < 0.05). Our results corroborate previous findings that the Whitetailed Kite is a rodent-specialist predator and suggest that in our study area it behaves as an opportunistic predator (i.e., capturing rodent prey in proportion to their availability). © 2009 The Raptor Research Foundation, Inc.