Feeding Ecology of Central Chilean Foxes, Dusicyon culpaeus and Dusicyon griseus

Abstract

We examined 318 scats of Dusicyon culpaeus and 278 of D. griseus, collected in central Chile between 1973 and 1978; they represented all seasons except winter. Both species preyed mainly upon rodents (diurnal, crepuscular, or nocturnal) that inhabited open vegetation patches. Frequency of occurrence of rodent prey items in the droppings tended to match their relative abundance in the field. Predation upon rabbits was rare and mainly on juveniles. A small number of birds, avian eggs, and snakes were eaten. Mean size of rodent prey remained constant from spring to fall, as estimated by the average dimensions of adult rodents represented in the droppings. Moreover, mean size of rodent prey did not differ significantly between fox species throughout the year. Numbers of droppings that contained berries increased from spring to fall. We concluded that central Chilean foxes were crepuscular, opportunistic predators that hunted in open patches of vegetation. Similarities in their feeding ecology suggest that competitive exclusion may be important in the maintenance of their allopatric distributions.