Humans Helped Vultures Colonize the Canary Islands

The Egyptian vulture population of the Canary Islands was established following the arrival of the first human settlers who brought livestock to the islands. A genetic comparison of Iberian and Canarian birds, published in the open access journal BMC Evolutionary Biology, found that the Egyptian vulture population in the Canary Islands was likely established around 2500 years ago -- around the same time as humans began to colonise the islands.

Rosa Agudo worked with a team of researchers from the Doñana Biological Station, Seville, Spain, to investigate genetic and morphological changes between 143 Iberian birds and 242 from Fuerteventura, one of the Canary Islands. She said, "We found that the island vultures are significantly heavier and larger than those from Iberia. The establishment of this insular population took place some 2500 years ago, matching the date of human colonization. Our results suggest that human activity can trigger divergent evolution and that this process may take place on a relatively brief time scale."

The authors suggest that before the arrival of humans, the Canary Islands would not have been able to support vultures, as food resources would have been scarce, consisting only of the remains of seabirds and sea mammals, or of rodents. They say, "The introduction of new and abundant food sources by humans could have allowed not only colonization by vultures, but also their demographic expansion and their putative adaptation to the new island environment." For once, human activity has actually assisted in the diversification and adaptation of the Egyptian vulture, now globally threatened and classified as 'Endangered' on the IUCN Red List.
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References:

Science Daily. 2010. "Humans Helped Vultures Colonize the Canary Islands". Science Daily. Posted: December 12, 2010. Available online: http://www.sciencedaily.com/releases/2010/12/101212194141.htm