A chronicling of long-standing carbofuran use and its menace to wildlife in Kenya - Carbofuran and Wildlife Poisoning: Global Perspectives and Forensic Approaches - page 76

hooded ( 62 %), Gyps ( 52 %), lappet-faced ( 50%), and white-headed ( 44%) vultures. The
authors attribute the declines to land-use changes outside the reserve, but further note that due to
declines seen inside the reserve, human activity, specifi cally poisoning, is suspected to be an impor-
tant cause of the declines. The wider Mara region has been the site of a growing number of poisoning
incidents and many vultures and other scavengers have been killed particularly in recent years
(Mijele 2009; Martins and Kahumbu 2009; Noonkipa, unpublished report).
Ogada and Keesing (2010) showed that over a three-year period raptors declined more than 40%
per year from 2001 to 2003 in Laikipia District (central Kenya). Overall, raptors declined by 70%
during the surveys and scavenging birds, particularly vultures, accounted for most of the decline
(Ogada and Keesing 2010). During the same period, overall populations of large wild herbivores
showed little change and domestic herbivores (particularly sheep and goats) increased, implying
that food limitation was not responsible for the observed declines. The authors suspected that the
rapid decline of vultures was due to consumption of poisoned baits laced with Furadan which
pastoralists were increasingly using to kill large predators that attacked their livestock (Odino and
Ogada 2008b). A report by Otieno and colleagues (2010b), discussed further in Section 3.6, which
follows, confi rmed the death of an African white-backed vulture ( Gyps africanus ) in Laikipia
District as a result of Furadan poisoning. Throughout Africa, hooded vultures ( Necrosyrtes mona-
chus ) have shown large declines (45 to 78%) over the past four to fi ve decades. In East Africa,
declines averaged 63%, with poisoning being a signifi cant factor suspected in their declines (Ogada
and Buij 2011).
Vultures provide one of the most important yet underappreciated ecosystem services of any
avian group (Sekercioglu 2006). As the only known obligate scavengers, they provide essential
ecosystem services, foremost of which is the disposal of rotting carcasses. In a sense, they are the
catalysts of carcass disposal. They can fl y quickly over large distances to locate and decompose
carcasses effi ciently and mammalian scavengers often follow them to carcasses. For this same rea-
son vultures may also be targeted by poachers because their presence or proximity can give away
the location of their camps (S. Thomsett, personal communication, 2010). Scavengers such as the
Marabou stork cannot easily feed on a carcass unless/until vultures have opened it, picked at it and
made it more accessible.
The potential consequences of vulture declines include changes in scavenger community com-
position and increased rates of disease transmission at carcasses. A recent study by Ogada, Torchin,
Ezenra et al. (in preparation) has shown that without vultures, carcasses decompose more slowly
(approximately 27 hours as opposed to 12) and greater numbers of mammalian scavengers spend
more time in close proximity to carcasses. One consequence was a 50-fold increase in the number of
contacts between mammalian scavengers, mainly hyenas and jackals. Such contacts between indi-
viduals were used as a proxy for disease transmission at carcasses as close contact between individu-
als is a likely source of pathogen transmission for a number of carnivore diseases including rabies
and canine distemper, for which hyenas and especially jackals are well-known hosts (Loehle 1995;
Murray, Kapke, Evermann et al. 1999). Based on the fi ndings, the authors (i.e., Ogada, Torchin,
Ezenra et al.) expect an increase in the spread of carnivore diseases at carcasses as vultures decline
or become locally extinct.
Vulture populations in Kenya are under serious threat particularly due to Furadan and carba-
mate poisoning. Although the evidence presented here is largely with respect to vulture studies
conducted in Kenya, further evidence links other countries in the East African region (in particular
Tanzania, Uganda and Ethiopia) to vulture declines as a result of Furadan and carbamate poison-
ing. If the current situation with regards to vulture poisoning continues, it is not unreasonable to
expect extinctions of most vulture species in Kenya within the coming decades with concurrent
ecological consequences for the scavenger community and increased rates of disease transmission
at carcasses.