Fewer Nests, Fewer Trees, More Poison: the Western Serengeti's Vultures
The African White-backed Vulture is the most numerous vulture of the African savanna, which is exactly why its numbers get quoted as if abundance meant safety. It was uplisted to Critically Endangered in 2015, and a new study from Tanzania's western Serengeti shows what that decline looks like at the sharp end: not in the sky, but in the trees where the birds nest.
56%
A team from the Grumeti Fund flew aerial surveys along the riparian forests of the Ikorongo–Grumeti Game Reserves and the Ikona Wildlife Management Area between 2013 and 2021, recording every vulture nest they found. Over nine years the nest encounter rate fell by 56% — a steep loss even by regional standards, in a landscape that is not short of protection.
The study, published in Ostrich: Journal of African Ornithology, was led by Vainess Laizer, a Tanzanian graduate student supported by The Peregrine Fund and the Grumeti Fund, with Dr Corinne Kendall and Dr Claire Bracebridge as co-authors.
29.4%
Ground surveys in 2021 and 2022 answered the next question: of the nests that do exist, how many produce a chick? In 2022, 29.4% did. Elsewhere in Africa the same species manages 55–57%.
That gap matters because of how vultures breed: slowly, and expensively. A pair raises one offspring at a time and invests months in it. A bad season is not a bad year; it is one bird fewer in the population for the next decade and a half, because vultures do not start breeding until they are four to six years old.
28%
Satellite imagery of the same area showed tree cover falling 28% between 2012 and 2020, and the nest surveys showed the birds concentrating in the sites that kept their canopy. Vultures need tall trees — riverine giants, for these populations — and they need them next to open country where carcasses appear. Losing a fifth of the cover means losing nest sites that the next rainy season cannot replace. The authors call for more work on what is actually removing the trees, which is not yet established.
The poison in the background
Nests are only part of the picture. In 2024, a single poisoning event in the Serengeti–Mara ecosystem killed more than 100 vultures. That is not unusual for the group: vultures feed communally, so one deliberately laced carcass can kill fifty birds in an afternoon.
The motive is rarely the vultures themselves. Most incidents involve livestock owners targeting predators, with vultures dying as bystanders, or the harvest of vulture body parts for belief-based use. Across the continent the White-backed Vulture is estimated to have declined by 63–89% over three generations, and regional figures are blunter still: in northern KwaZulu-Natal, breeding pairs are down 70–80% since 2004, with the northernmost cluster losing 81% since 2012.
Why this matters outside Tanzania
Vultures are the savanna's sanitation department. A flock — a kettle, when they are circling — can strip a carcass to bone in hours, removing the anthrax, brucellosis and rabies risk before it reaches livestock, wildlife or people. Where vultures disappear, the cost of that service reappears as disease and as carcasses that stay where they fell. They are also, grimly, the fastest detector of a poisoning incident: the birds die where the poison is, which is how most events are discovered at all.
Where the numbers are moving the other way
Southern Africa holds one vulture that exists nowhere else: the Cape Vulture. It nests on cliffs in colonies that can hold hundreds of pairs along the Great Escarpment, and the Maloti-Drakensberg alone holds an estimated 900–1,450 breeding pairs, roughly a fifth of the global population. South Africa gazetted a national Biodiversity Management Plan for Vultures in 2024, built around protecting adult survival — poisoning the adults is what drives a collapse, and it is also the threat that intervention can reach fastest.
Telemetry is how you find the problem. In April 2026, Wildlife ACT and Ezemvelo KZN Wildlife fitted 19 GPS units to White-backed Vultures in Hluhluwe-iMfolozi Park, the largest single tracking deployment for the species in that province's history, and Lappet-faced Vulture chicks were tagged from a helicopter for the first time in KwaZulu-Natal in early 2026. Those tracks answer the question the Serengeti study raises: where are the adults going, and where are they dying?
Listening to vulture country
Vultures themselves are almost silent — food is found by sight, so there is no need for a call that carries. The woodland they nest in is the opposite. These are three voices from the same East African savanna habitat where the study's nests were counted; our archive holds 54 Tanzanian species in total, and these are among them.