14 agosto 2009

Rapid evolution may be reshaping forest birds’ wings

Human activities that leave forests in fragments are influencing bird morphology! Birds have pointier wings in heavily logged boreal forests, while blunter, rounder ones in reforested parts of New England.

In areas of Canada where loggers have chewed away the conifer forest that once blanketed most of the country, the long wing feathers, or primary feathers, of 21 mature-woodland species of birds has overall gained about 2.23 millimeters on average during the past century. That uptick roughly matches the magnitude of differences between sexes. In contrast, species from areas in New England (deforested during previous years but rebounded into green woodland again) have a trend back toward rounder wing tips. Eight mature-woodland species had lost, on average, some 2.37 millimeters on those long primary feathers.

"Birds aren’t passive victims of environmental change. As bird species face new challenges, they respond to the extent they can. Birds are not like sitting ducks," said André Desrochers of the Center for Forest Research at Laval University in Québec City during a report he presented on August 13 in Philadelphia at a meeting of the American Ornithologists’ Union..

Desrochers argues that rapid evolution is the most straightforward explanation for his findings.

By ScienceNews, contributed by Susan Milius

Read full story at: http://www.sciencenews.org/view/generic/id/46471/title/Rapid_evolution_may_be_reshaping_forest_birds%E2%80%99_wings

0 comentarios:

Publicar un comentario en la entrada

Gracias por tu comentario, será publicado en breve! Tus comentarios alimentan mi blog!
Thanks for your comment! It will be published shortly. Your comments feed my blog!