22 Dec 2010
Study shows alarming drop in Kenyan vultures
Vultures in one of Africa’s most significant wildlife reserves are declining at an alarming rate according to a new study in Biological Conservation.
Researchers found that vulture populations – including African White-backed Gyps africanus, Ruppell’s Gyps reuppellii, and Hooded Necrosyrtes monachus - around the Masai Mara National Reserve in southwestern Kenya have dropped up to 60 percent over three decades.
The primary causes are changes in land use and other human activity, particularly the poisoning of livestock carcasses intended to kill lions and other large predators. Vultures quickly die after scavenging on the tainted carcasses.
“Staggering declines in abundance were found for seven of eight scavenging raptors surveyed,” said co-author Munir Virani. “Better land management and a ban on certain pesticides are needed to preserve these keystone members of the scavenging community.”
“The situation in Kenya perhaps mirrors the situation throughout eastern Africa,” Virani said. “This is the first time that large-scale population declines in vultures and other scavenging raptors in and around the Masai Mara have been documented.”
Vultures scavenging on a Thompsons Gazelle in Maasai Mara, Kenya.
Another study published in early 2010 by the Journal of Raptor Research showed similar trends, revealing declines of 70 percent for scavenging birds, primarily vultures, over a three-year period in central Kenya. The authors determined that food and weather were not limiting factors and suggested that poisoned bait was responsible for the die-offs.
The latest study compared trends between the migration season of large ungulates like wildebeest and the non-migration season on reserve, buffer, and grazed lands. Large declines in all areas, including the reserve, during the ungulate migration - when food supplies are abundant for vultures - suggest that they are affected well beyond the study area.
In many areas, livestock owners misuse a pesticide called Furadan to poison lions and other large predators that kill their livestock. They set out a carcass laced with the poison, which is subsequently scavenged by vultures. Because they are social animals that feed together, many vultures can be killed by a single poisoning event.
Scavengers occupy an essential niche in the ecosystem as a clean-up and recycling crew. Vultures quickly consume the carcasses of dead animals before they decay and develop diseases harmful to humans, livestock and wildlife.
Paul Matiku, Executive Director of Nature Kenya (Birdlife Partner) said: “if the use of Furadan and other chemicals like Dichlophenac are not removed from the Kenyan market, Kenya is likely to not only lose all the wildlife but also wipe out the entire vulture populations and other target species”.
The BirdLife Africa Partnership and many other conservation organisations across Africa are working to address the problems caused by avian poisoning, and are calling for increased concerted efforts to deal with the rapidly intensifying problem.
Furthermore, a survey has been undertaken on the use of chemicals in BirdLife network countries in Africa, and the BirdLife Secretariat and Partners are lobbying relevant authorities to inform them of the extent of the problem and urge increased vigilance.
With funding from the Rufford Maurice Laing Foundation - through the RSPB (BirdLife in the UK) - over 2,000 posters have been produced to raise awareness of the threat to vultures; and coordinated counts are being undertaken in East Africa to verify the extent of the problem and make recommendations for mitigation.
The recent Kenyan study was conducted by The Peregrine Fund, National Museums of Kenya, and Princeton University and was published in Biological Conservation (click here for abstract).
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