Egyptian vultures on the Canary Islands provide evidence that human caused environmental change can lead to animal evolution in relatively short time periods. But human impact have recently caused a dramatic drop in the bird's numbers worldwide.

Egyptian vultures (Neophron percnopterus) may have followed human migrants to the Canary Islands about 2500 years ago. The Berber people of northern Africa brought with them goats, which then became an abundant food source for the vultures.

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Unlike cases where invasive species out-compete native animals for food sources, the vultures seem to have been feeding on mostly the carcasses of dead domesticated goats. Human expansion often causes animal extinction, but in this case the Egyptian vultures found a new habitat and show signs of developing into a genetically distinct sub-population.

The vultures of the Canary Islands are 16 percent heavier and 3 percent larger than those of Spain and Portugal, according to Rosa Agudo and a team of researchers from the Doñana Biological Station, Seville, Spain in a paper published in BMC Evolutionary Biology. The Canary Island population also shows genetic differences from the mainland population.

The researchers noted that these results suggest human caused environmental change can lead to animal diversification in about 200 generations for these birds.

Currently, humans are doing little to help the spread and survival of the Egyptian vulture populations. The bird is listed as endangered on the International Union for Conservation of Nature red list.

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In India, veterinary use of the drug Diclofenac may be largely responsible for the crash in vulture and other carrion bird populations. The Egyptian vulture population declined by 90 percent in India during the past decade.

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The anti-inflammatory drug, Diclofenac, builds up in the bodies of vultures after eating cattle treated with the drug. The birds then die, most likely of kidney failure. This has caused numerous problems, including an explosion of feral dog populations and the rabies they carry.

The loss of vultues has religious implications for Zorastrian Parsi communities, who rely on the vultures to dispose of human corpses laid to rest in Towers of Silence.

Diclofenac is being phased out in India. But a Brazilian company, Ouro Fino, is now selling it to several African nations. Ornithologists and others worry that Diclofenac may cause similar problems in Africa.

PHOTO 1: The Egyptian Vulture; Wikimedia Commons