Large birds have all but disappeared from the Sahel.
Two identical bird counts conducted 30 years apart have revealed a catastrophic decline in numbers of large birds in the sub-desert region of West Africa.
Jean-Marc Thiollay travelled the same 3,700 mile routes in 1971-73 and 2004. Birds still relatively common in the 1970s, including Nubian and Arabian Bustards, Ruppell’s Griffon and Lappet-faced Vultures, had entirely disappeared by 2004. Additionally thiollay says the Ostrich, once widespread, is now extinct west of Chad. Egyptian Vulture numbers over a large section of the route had dropped from 75 in the early survey to just one.
‘Over hunting, aggravated by overgrazing and degradation of acacia woodlands are obvious causes of the collapse of Ostrich and bustards,’ he writes in a recent paper published in Bird Conservation International. The near-extinction of wild ungulates (antelopes & gazelles), intensified use of cattle, increased disturbance and poisoning of predators may have been critical in the dramatic decline of vultures.’
He adds ‘An effective hunting ban, updates on the status of threatened species, reintroduction of Ostrich, enforcement of existing nature reserves and design of a new one in northern Mali are among the most urgent steps to take if the large birds of the vast sub-desert areas of West Africa are to be conserved.’
Accordingly Ruppell’s Vulture, Egyptian Vulture, White-backed Vulture and White-headed Vulture will now probably be listed by BirdLife as threatened on the forthcoming 2007 IUCN Red List.
The ‘slow but continued’ desertification of the Sahel identified by Thiollay may also have had an impact on over-wintering Palearctic warblers. The research suggests that Common and Lesser Whitethroat and Sub-alpine Warbler can cope with all but the most severely degraded habitat. But the loss of key habitats at departure points prior to spring migration means that birds are unable to build up their fat reserves, which may force them to depart from further south. The greater distance, added to the existing barrier of the Sahara, may lead to increased mortality on migration, and to birds arriving on their breeding grounds late and in poor condition.
‘Over hunting, aggravated by overgrazing and degradation of acacia woodlands are obvious causes of the collapse of Ostrich and bustards,’ he writes in a recent paper published in Bird Conservation International. The near-extinction of wild ungulates (antelopes & gazelles), intensified use of cattle, increased disturbance and poisoning of predators may have been critical in the dramatic decline of vultures.’
He adds ‘An effective hunting ban, updates on the status of threatened species, reintroduction of Ostrich, enforcement of existing nature reserves and design of a new one in northern Mali are among the most urgent steps to take if the large birds of the vast sub-desert areas of West Africa are to be conserved.’
Accordingly Ruppell’s Vulture, Egyptian Vulture, White-backed Vulture and White-headed Vulture will now probably be listed by BirdLife as threatened on the forthcoming 2007 IUCN Red List.
The ‘slow but continued’ desertification of the Sahel identified by Thiollay may also have had an impact on over-wintering Palearctic warblers. The research suggests that Common and Lesser Whitethroat and Sub-alpine Warbler can cope with all but the most severely degraded habitat. But the loss of key habitats at departure points prior to spring migration means that birds are unable to build up their fat reserves, which may force them to depart from further south. The greater distance, added to the existing barrier of the Sahara, may lead to increased mortality on migration, and to birds arriving on their breeding grounds late and in poor condition.
