Super-predation, where a top predator preys on another predator, is widespread in Europe, a study finds. But it is hard to film in the wild. Here, researchers use a trained eagle owl and mounted tawny owl to illustrate the behaviour.
Eagle owls hunt foxes, for example. This dead fox was found in an wild eagle owl nest, and researchers allowed a trained owl to attack it to illustrate what happens naturally.
The study, published in the journal Population Ecology, examined the feeding habits of four large raptors that occur in Europe: the goshawk, golden eagle, Bonelli's eagle and eagle owl (above).
These birds (goshawk above) prey on other predators such as tawny owls, kestrels and foxes, analyses of their diets reveal. However, preying on another predator is risky, carrying a high risk of injury. It occurs when food such as rodents become scarce.
It also happens more often in places such as central Europe, where people have altered habitats, decreasing numbers of normal prey such as birds or small mammals, says researcher Rui Lourenco of the University of Evora, Portugal, who conducted the study.
Super-predation, such as this young eagle owl feeding on a little owl near a nest, may play a significant and under-appreciated role in the workings of some ecosystems, say the researchers.
What are these?