North America has lost 3 billion birds in 50 years, 29 percent of avian populations have vanished from our skies, including birds in every ecosystem – from backyard birds and meadowlarks to songsters and swallows according to U.S. and Canadian researchers report this week online in Science.
“It’s staggering,” says first author Ken Rosenberg, a conservation scientist at the Cornell University Laboratory of Ornithology. The findings raise fears that some familiar species could go the way of the passenger pigeon, a species once so abundant that its extinction in the early 1900s seemed unthinkable.
The results, from the most comprehensive inventory ever done of North American birds, point to ecosystems in disarray because of habitat loss and other factors that have yet to be pinned down, researchers say. Yet ecologist Paul Ehrlich at Stanford University in Palo Alto, California, who has been warning about shrinking plant and animal populations for decades, sees some hope in this new jolt of bad news: “It might stir needed action in light of the public interest in our feathered friends.”
In past decades, Ehrlich and others have documented the decline of particular bird groups, including migratory songbirds. But 5 years ago, Rosenberg; Peter Marra, a conservation biologist now at Georgetown University in Washington, D.C.; and their colleagues decided to take a broader look at what is happening in North America’s skies. They first turned to the North American Breeding Bird Survey, an annual spring census carried out by volunteers across Canada and the United States, which has amassed decades of data about 420 bird species. The team also drew on the Audubon Christmas Bird Count for data on about 55 species found in boreal forests and the Arctic tundra, and on the International Shorebird Survey for trends in shorebirds such as sandpipers and plovers. Aerial surveys of water bodies, swamps, and marshes filled out the picture for waterfowl. Altogether, they studied 529 bird species, about three-quarters of all species in North America, accounting for more than 90% of the entire bird population.
Some species have seen an uptick in numbers, such as bald eagles after DDT pesticides were banned and legislation was passed to help protect the birds. Waterfowl management has allowed ducks and geese to thrive, while vireos, a mostly insect-feeding bird, have grown by more than 85 million, with scientists not entirely certain why their numbers are booming.
“These are important examples that show, when we choose to make changes and actively manage the threats birds face, we can make positive changes for birds and the environment as a whole,” said Rosenberg. “Nature is resilient, and our study indicates that action is urgently needed, but it is not too late to save birds and our natural world.
So how can you help?
Make glass windows more visible if birds are flying into them – millions die each year from window collisions. You can also help conservation efforts of bird-rich habitats and support policy such as strengthening the Migratory Bird Treaty Act, says Michael Parr, president of American Bird Conservancy.
“Birds don’t recognize political boundaries – migrating birds especially cross many countries and to protect them for their entire life cycle we need to address problems on breeding grounds, migratory routes, and wintering grounds as well as the crucial stopover habitats they use along the way,” said Rosenberg. There needs to be international cooperation that makes preserving nature a priority.”
“The story is not over,” Parr added. “There are so many ways to help save birds.”
