March 26, 2013
Pacific Island Birds Vanished Without A Trace After The Arrival Of Man
April Flowers for redOrbit.com - Your Universe Online
The last region on Earth to be colonized by humans was home to more than 1,000 species of birds that went extinct shortly after people reached their island homes, new research from the Zoological Society of London (ZSL) and collaborators reveals.
Tropical Pacific Islands, like Hawaii and Fiji, were an untouched paradise almost 4,000 years ago when the arrival of the first people caused irreversible damage with overhunting and deforestation. Many birds disappeared as a result, but uncertainties in the fossil record have constrained our understanding of the sheer scale and extent of these extinctions.
Professor Tim Blackburn, Director of ZSL's Institute of Zoology says, "We studied fossils from 41 tropical Pacific islands and using new techniques we were able to gauge how many extra species of bird disappeared without leaving any trace."
After the first humans arrived on these islands alone, 160 species of non-passerine land birds — non-perching birds with feet designed with specific functions, such as webbed for swimming — became extinct without a trace.
The largest order of birds is comprised of passerines, or songbirds, representing over half of the world's total bird species. Passerines include such birds as flycatchers, birds of paradise, crows and many well-known garden birds. Non-passerines comprise all other birds. Though some non-passerines spend most of their life at sea, such as shearwaters and albatrosses, all of them nest on land.
"If we take into account all the other islands in the tropical Pacific, as well as seabirds and songbirds, the total extinction toll is likely to have been around 1,300 bird species," Professor Blackburn added.
The list of lost species includes several species of moa-nalos (large flightless birds from Hawaii), and the New Caledonian Sylvionis (a relative of game birds like pheasants and grouse, which weighed in around 65 pounds).
The study, published in Proceedings of the National Academy of Sciences, shows that certain islands and species were especially vulnerable to overhunting and habitat destruction. More species were lost from small, dry islands because they were deforested more easily and had fewer hiding places from hunters. The type of bird made a difference as well, with flightless birds being over 30 times more likely to become extinct than those that could fly.
The loss of bird species in the Pacific has not stopped. After the arrival of Europeans, at least 40 more species have disappeared and many more are facing extinction today.