Kleptoparasitism from condors to eagles mediated by an exotic prey

Abstract

The presence of alien invasive species can enhance competitive interactions between native species. A common type of direct competition is kleptoparasitism, i.e., the theft of food. This foraging strategy is closely linked to scavenging and can represent a central source of food for some populations and species. Here, we describe novel observations of an obligate scavenger, the Andean condor (Vultur gryphus), stealing invasive European hares (Lepus europaeus) hunted by a large raptor, the Black-chested Buzzard eagle (Geranoaetus melanoleucus), in southern Argentina. We re-analyzed data on food habits of sympatric, obligate scavengers to show that Andean condors consume more hare than two smaller vultures. Our observations suggest that the prevalence of European hare in the diet of Andean condors is partially due to opportunistic kleptoparasitism of the Black-chested Buzzard eagle. We propose that condors kleptoparasite eagles regularly, with cascading consequences for the population dynamics of condors, eagles, and hares. Our observation illustrates how novel food resources generated by invasive species can lead to new context-dependent competitive interactions between obligate scavengers and apex predators.