Monday, September 22, 2008

Birds and Biodiversity

Many of the world's bird species are in serious decline.

The report highlights worldwide losses among widespread and once-familiar birds. A staggering 45% of common European birds are declining [1]: the familiar European Turtle-dove Streptopelia turtur, for example, has lost 62% of its population in the last 25 years. On the other side of the globe, resident Australian wading birds have seen population losses of 81% in just quarter of a century [2].

Twenty North American common birds have more than halved in number in the last four decades [3]. Northern Bobwhite Colinus virginianus fell most dramatically, by 82%. In Latin America, the Yellow Cardinal Gubernatrix cristata - once common in Argentina - is now classified as globally Endangered [4].

Millions of White-rumped Vultures Gyps bengalensis recently flew in Asian skies. In just sixteen years populations have crashed by 99.9% - the species is now classified as Critically Endangered [5]. Widespread birds like the Eurasian Eagle Owl are believed to be vanishing from Middle Eastern forests [6]. Seabirds - including Critically Endangered Chatham Albatross Thalassarche eremita - are disappearing from the world’s oceans [7].
While in some cases these declines may simply indicate a problem with a single species, in many cases they signal larger problems with their ecosystems. It could be population crashes among prey species (e.g., due to overfishing), habitat changes (e.g., loss of farmland), or some other problem. So some conservationists suggest that the reductions in many bird populations indicate a wider biodiversity crisis.