Darcy Ogada rarely spots raptors from her home in central Kenya any more. The birds were once a common sight in the industrial town of Thika, 25 miles (40km) north of Nairobi, but the region’s forests are rapidly declining, and the few remaining raptor populations face the added threats of poison and persecution.
“It is a disaster,” says Ogada, “Every day I go out of the house and look into the sky, I am disappointed. I might see the extinction of these birds in my lifetime. “
Ogada works for the Peregrine Fund and was among a team of Kenyan and international scientists who recently published a report detailing widespread declines of Kenya’s birds of prey over the past 40 years. Numbers of common kestrel were down by 95%; secretary bird and long-crested eagles 94%; lesser kestrels 93%; and the augur buzzard down 91%. Both the hooded vulture and Montagu’s harrier saw an 88% decline.
“We are on the brink of losing many of them, along with the environmental benefits they confer to humanity,” says Peter Njoroge, head of the ornithology section at National Museums of Kenya. “Most birds of prey are slow breeders and cannot cope with the myriad threats they face unless urgent action to protect them is initiated.”
The study, published in February in the Biological Conservation journal, involved a team of scientists from Kenya, the UK, France and the US, who conducted road surveys from 2003 until 2020, covering routes previously surveyed in the 1970s. They measured changes in raptor numbers between the two periods to identify species showing significant declines and gauge the effectiveness of protected areas.
According to the scientists, factors contributing to rapid raptor decline include habitat fragmentation as a result of infrastructure development, widespread deforestation and a sharp rise in human population growth, which has resulted in a landscape that is less resilient to the effects of the climate crisis. Agriculture and livestock development have also led to degraded ecosystems unable to sustain wildlife.
“A sharp increase in livestock numbers in recent decades has led to overgrazing, reducing grass cover and small mammal populations, diminishing the prey base for raptors. The result is a biologically impoverished landscape that is less resilient to climatic changes and provides fewer ecosystem services, and where attitudes toward wildlife have become increasingly intolerant, ”says the report.
Raptor numbers declined less severely in parks and reserves compared with unprotected lands, underlining the importance of protected areas for remaining populations, say the researchers.
“Our findings highlight the stark contrast between raptor trends in protected areas and in unprotected land. Outside Kenya’s protected area network there is evidence that raptor populations have almost collapsed, and this cuts across species size, diet or ecological requirements, ”says Philip Shaw at the University of St Andrews.
Simon Thomsett, a director at Kenya Bird of Prey Trust, a raptor rescue and rehabilitation organization, says there has been little effort to save raptors compared with animals such as elephants, lions or rhinos, which rank highly in the tourism world.
“You have some conservationists who judge the health of the ecosystem with the increase in elephants. But the elephant would hardly survive if the raptors were not there to clean up the environment, ”he says. “If the figures [of raptor decline in Kenya] were witnessed in Europe, Japan or any other part of the developed world, there would be panic and people would do everything to save them. We have seen people getting permits to have noisy social events in places like Hell’s Gate national park in the Rift valley where Rüppel’s vultures breed, with long-term effects on the raptors. “
The experts are also concerned about deliberate and incidental poisoning of raptors, and fear the long term effects of recent large-scale spraying of locusts in northern Kenya on raptors that fed on the dead insects. The UN’s Food and Agriculture Organization says: “Chemical pesticides used in locust control can pose risks to human and animal health… Some do pose low to medium risk to mammals, including domestic livestock and fish. Most present high risks to honeybees and other beneficial species. “
Poisons used to kill predators such as lions and hyenas that attack livestock are also taking their toll on birds of prey. While the poison may succeed in killing a few predators, it is raptors, especially vultures, that die in large numbers.
Thomsett says: “Farmers may be targeting hyenas, but it is the vultures that eat the carcasses. Now, we are having plenty of carcasses with fewer scavengers. Killing a raptor is still a wildlife crime like killing a rhino, yet we rarely hear of any arrests as a result of killing a raptor. “
Despite the threats to Kenya’s raptors, the authors suggest that declines could be reversed through enhanced management of protected areas, the mitigation of specific threats, and the implementation of species recovery plans.