Vultures May Need More Protection in Africa

Nicknamed “flying garbage men,” vultures have a key job in the ecosystem: cleaning up carrion and other waste.

Some people consider them a nuisance, but they are critical to their habitats, removing carcasses which in turn limits the spread of wildlife disease. Researchers are concerned because their population is declining and they need more protection.

In a new study, an international team of scientists compared the movement of three species of threatened vultures across Africa. They found that their home ranges can be much larger than areas designed to protect them, which puts their numbers at risk.

“I like vultures for lots of reasons,” lead author Adam Kane of University College Dublin tells Treehugger. “I find social animals interesting because they mirror us, but vultures also have this unique ecology where they rely on carrion, their whole biology is modified for this mode of life.”

Vultures have naked heads, which allows them to easily dine on the bodies of dead animals without messing up their feathers. They also have digestive systems designed to eat diseased or rotting food without making them sick.

Studying Vultures

For their research, the team studied the home ranges of three species of vultures. They analyzed how those ranges overlapped with protected areas. Their data included 163 birds: the African white-backed vulture (Gyps africanus), Rüppell’s vulture (Gyps rueppelli), and the Cape vulture (Gyps coprotheres).

Both the African white-backed vulture and Rüppell’s vulture are listed as critically endangered by the International Union for the Conservation of Nature (IUCN) and the Cape vulture is classified as vulnerable to extinction.

Researchers analyzed information from birds that had been captured and tagged in 18 countries over a 15-year period in eastern and southern Africa. They compared that data to information on species, age, breeding status, season, and region.

“Tagging animals requires a huge amount of effort but lots of people were doing it across the continent, so it made sense to team up rather than try a piecemeal approach with everyone doing their own thing,” Kane says. “This mass of data also gives us more confidence in our results. There's less probability that what we found is due to random chance.”

The main threat to the vultures is poisoning. Birds can be the intentional or accidental target of poison. They might eat environmental poisons such as agricultural pesticide or dine on poisoned baits typically used to control carnivore predators.

In June 2019, for example, at least 537 vultures were killed near Botswana’s Chobe National Park, with the slaughter linked to elephant carcasses that had been spiked with poison.

Dwindling Protection

Research found that the vultures have some of the largest ranges of any terrestrial, non-migratory species.

Adult white-backed vultures have home ranges of about 24,000 square kilometers in east Africa and 31,500 square kilometers in southern Africa. Cape vultures average 36,000 square kilometers and Ruppell’s vultures cover 75,000 square kilometers.

They found that younger birds, who have difficulty competing for food, cover larger areas than adults. Birds that are breeding stay in smaller areas. And there are seasonal changes in sizes when food is more or less abundant.

Because they travel so much, they often fly over unprotected areas. The Cape vulture, for example, has a home range that only overlaps 34% with protected areas for adults and 16% for immature birds.

The findings were published in the journal Biological Conservation.

Vulture Conservation

There are vulture safety zones (VSZ) in Africa where poisoning isn’t allowed, but researchers say these protected areas aren’t large enough to help the birds. And more conservation measures are necessary.

“I think it emphasizes the challenge vulture conservation poses to us,” Kane says.

“The birds range over huge areas, including large tracts of unprotected country. The idea of applying so-called vulture safe zones—areas that match to the bird's home range and that are free from poison—would be hugely difficult to enact. Our work speaks to the importance of cross-border collaboration when it comes to conservation.”