Predator feeding ecology on Patagonian rocky outcrops: implications for colonies of mountain vizcacha (Lagidium viscacia)

On 10 rocky outcrops with mountain vizcacha colonies, diets and trophic relations of five predator species were analyzed to evaluate their impact in vizcacha populations. Diets included 17 prey items of which mammals represented 97% of biomass. Lagomorphs were the most important prey, followed by sigmodontines, tuco-tucos, and mountain vizcachas. The Barn Owl was a specialized predator, while the culpeo and lesser grison were generalized consumers. Predation of mountain vizcacha by Magellanic Horned Owls and culpeo foxes could increase vizcacha vulnerability because vizcacha populations are small and fragmented, and females produce only one offspring per year.