|Know your wildlife with Tsitsi S Maponga|
|Saturday, 14 July 2012 18:50|
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Scavenging by avian, mammalian speciesSCAVENGING by large-bodied vertebrates is observed in many ecosystems but has rarely been quantified. The opportunity to scavenge is determined by the availability of carcasses, which depends on the number of animals dying from causes other than predation and the number of prey killed by predators in the area.
Consumers present at a carcass are influenced by the amount of carrion present; if the total amount of carrion is small then it will be consumed primarily by those scavengers that are the first to arrive and/or competitively dominant. If the amount of carrion is larger than that which can be consumed immediately by local scavengers, then consumers should continue to arrive from more distant areas.
Some vertebrates, such as hyaenas and various raptors, use carrion frequently, whereas others scavenge only rarely. Nevertheless, even a species that is not typically associated with scavenging occasionally will eat carrion. The use of carrion by a vertebrate species is influenced by the speed and efficiency with which it forages and feeds, its visual and olfactory abilities, and its capacity for detoxifying products of decomposition.
It is suggested that carrion resources are more extensively used by vertebrates than have been widely assumed:
1) a substantial number of animals die from causes other than predation and become available to scavengers.
2) a wide variety of vertebrate scavengers, rather than microbes or arthropods, consume most available carcasses, and
3) intense competition exists among and between vertebrate scavengers and decomposers, especially in warm climates.
Origins of carcasses
When herbivores die, their carcasses provide food for diverse scavengers and decomposers, including vultures. Avian scavengers, through their flight and mobility, are well suited to track this resource, each species with differences in biology that determine when, where and what sort of carrion each finds, whereas, mammal scavengers primarily use odour cues to locate carcasses.
Human-caused mortality, namely hunting, might be an important carcass supplier in some areas. The offals and occasionally some of the meat may be dumped in places which could be scavenger (vulture) “restaurants” and in the wildlife areas in which they are located they particularly attract Hooded vultures.
Crocodile farms also have their dumps which attract vultures, Marabou Storks are especially attracted to all these localities. Human hunters also provide such subsidies to scavengers when they leave behind the entrails of their kills.
The excess meat after distribution to the locals is left in the rubbish pit and at night, spotted hyaena can use carcasses leftovers without any disturbance. On this regard conservationists have long been concerned about the effects of human disturbance on wildlife. Among the numerous reported effects, it has been suggested that disturbance can scare animals away from preferred feeding areas.
The most obvious reason why animals flee from humans is because they perceive humans as potential predators and respond accordingly.