Human activity is the greatest cause of extinctions around the world, according to the first global assessment of threats to birdlife. The study reveals that a move towards industrialisation and intensive farming, more than the mere growth in human population, is the single biggest threat to life, forcing more species to the brink of extinction than any other factor.

Species can go into dramatic declines for a number of reasons. Birds living on small islands, or in desert or mountainous regions, can be vulnerable to slight changes in climate, while even minor disruptions of forest habitats can affect the breeding habits and survival of others. Conservationists often find it hard to untangle the most serious threats to different species.

Using an unprecedented map of nearly 10,000 bird species, an international team of conservationists assessed the greatest threats to them around the world. After dividing the world into squares 100km wide, the researchers fed in details of each bird species living there and their risk of extinction, as defined by the World Conservation Union. They then added information on the local habitat and terrain, the weather variability and estimations of how much of the country`s gross domestic product was generated by the patch of ground.

"What surprised us was that if you do this analysis regionally, a variety of factors come out as being the biggest drivers of extinction. It is only when you take the global view that the impact humans are having really becomes apparent," said Professor Tim Blackburn, a biologist at Birmingham University.

The researchers produced maps pinpointing regions where birds are most likely to become extinct in the near future, including the Indo-Malayan realm, Madagascar, the Andes, Amazonia and the Atlantic coastal forests. In some regions, it is the hunting of birds, for sport or to trade their pelts, that is the greatest threat. Parrots and pheasants were among species that emerged as seriously threatened, but the list also includes kiwis, disappearing from all parts of New Zealand, cranes and even pigeons. The study appears today in the journal Proceedings of the Royal Society B.

Many bird species are already seriously in decline. A recent study from Stanford University concluded that by the end of the century, 10% of the world`s bird population will have become extinct with a further 15% dangerously close to the brink.
(By Ian Sample, The Guardian, 07/06/2006)
http://www.guardian.co.uk/conservation/story/0,,1792012,00.html