When Food Runs Out, Top Predators Turn on Each Other

Neighbours become rivals

What happens when two top hunters sharing the same woods run out of food? For decades, wild lynx and big birds of prey called kites lived side by side without trouble. Both fed on wild rabbits, sharing the land in peace. But an observational study—research that tracks wildlife in the wild without direct lab tests—shows that harsh stress can flip this calm balance upside down.

The breaking point

First, an emergent disease, or new spreading illness, swept through the wild rabbits, causing their numbers to collapse. Then a dry spell, known as a drought, parched the land. With prey scarce, lynx began to prowl near trees where kites nested. Below these perches, the cats found leftover rabbit scraps dropped by the birds. Seeing a rival eating what little meat was left, the cats began killing the birds to cut down food competition.

Ripples down the food chain

These attacks dealt a heavy blow to the birds. The danger reduced their lifetime reproductive success, meaning the kites raised far fewer young over their entire lives. To stay alive, many adult kites gave up their home ranges and flew away. That sudden retreat triggered shifts across lower trophic levels, which are the feeding steps in a food chain. With fewer big kites hunting overhead, numbers of a small insect-eating owl quickly grew.

Why tracking this matters

Scientists care about these observational records because they show how human-driven shocks, like climate swings and disease, can push calm wildlife into direct conflict. Still, this research looked at one local group of cats, kites, and owls without measuring wide areas across the globe. Ecologists do not yet know how deep a drought must be to set off this lethal rivalry in other habitats. The long-term evolutionary outcome of this new clash between the hunters also remains unknown.