How Scrounging Vultures Track Down a Meal: Following Eagle-Eyed Raptors

Vultures prey on the dead and the dying. Now, though, researchers have found out exactly how they hunt down their prey. It turns out that these birds use social cues from keen-eyed birds of prey in order to locate food before swooping down in large groups to steal freshly-killed meals.

In order to learn a bit more about vultures, the researchers focused on two species that live in Kenya. Using a combination of economic game-theory models and data from fieldwork, the scientists examined the vultures' feeding habits and behavior.

"We filmed interactions between eagles and vultures feeding at animal carcasses and our videos confirmed that eagles use their keen eyesight to find carcasses first, while the vultures simply 'scrounge' this information by following them to the carcasses," said Adam Kane, one of the researchers, in a news release. "That's not to say the eagles are the losers here. By arriving earlier, they get their finder's bonus and can continue on with some hunting once displaced; a strategy that vultures can't rely on."

The vultures don't just follow eagles, though. They also use the eagles as a way to better access food. Eagles have the ability to tear open carcass hides with their strong beaks, a talent that vultures lack. This means that the vultures will wait for the eagles to do the work before swarming en masse and then taking the feast for themselves.

These findings don't just tell researchers a bit more about animal behavior, either. They're crucial for understanding how best to protect these species in the future.

"Vultures were once the most abundant birds of prey in the world, but their numbers have been hammered in recent decades by habitat loss, inadvertent poisoning and hunting," said Andrew Jackson, who supervised the research. "Our study shows, as is often the case in the tangled web of ecology, that it is important to consider other species when trying to conserve vultures. In this case, conserving early rising raptors may help to boost the chance that vultures will find enough food to survive."

The findings are published in the journal Proceedings of the Royal Society B: Biological Sciences.