Friday, September 19, 2014

Extinction for 314 Birds, Including Eagles?


In the 1970s in Maryland I could only see bald eagles in cages.  By the 2000's, I lived a half mile from an eagle nest in Maryland, about 15 miles from the U.S. Capitol building.  And within two weeks of moving to Ohio, in 2012, I saw an eagle's nest about 5 miles from my new home.  Now, climate change threatens a second attempt at extinction for our Nation's symbol.  (Photo by Debbie Hurlbert, Howard, Ohio)
Pick a favorite bird that comes to your yard and it’s probably one of the 314 North American bird species at risk from climate change, according to a recent Audubon report, based on a  seven-year study of 588 species by Audubon’s science team.  The report is published in Audubon Magazine’s special issue, titled “Birds & Climate Change.”

The study suggests that “Nearly half of the bird species in the United States will be seriously threatened by 2080, and any of those could disappear forever.”

Shockingly this would also mean the reversal of one of the biggest conservation success stories, the revival of the bald eagle in my lifetime.  The study projects the bald eagle could lose 71 percent of its current range by 2050.  The report says, “It may see a 56 percent range expansion into areas opened up by global warming, but it will still need prey and nesting habitat in those new areas.”  That means that both their prey and their desired nesting trees must also survive global warming in their new areas, if the bald eagle is to survive there.

The same is true of the golden eagle, whose “breeding range is forecast to shrink 58 percent by 2050 and 79 percent by 2080, although it could potentially colonize new areas,” the report says.

No Loons in Minnesota

As the climate continues warming, all 314 species could lose their preferred habitats.  For example, loons are predicted to be totally gone from Minnesota as its climate warms, shrinking their non-breeding range by 63 percent and their summer breeding habitat range by 32 percent.   Shrink enough and the loons could be extinct.  That’s the basic idea with all the species-on-the-brink listed.

The study used hundreds of thousands of birdwatcher observations for the Audubon Christmas bird counts and the North American Breeding Bird Survey to determine each species’ “climate envelope”.  This envelope pinpoints the range of temperatures, rainfall amounts, and other climate characteristics of the habitats occupied by each species.  As the report states, “Then they looked for each combination of characteristics within sophisticated computer projections of the global climate, finding the future climate envelopes—and, by extension, the potential future ranges—of the species and mapping them to a resolution of 10 square kilometers.”

The study divides the 314 birds into two categories:  188 “climate-threatened” and 126 “climate-endangered”.   The climate-threatened birds” face losing more than half of their current range by 2080, although they have the potential to shift into new areas.”  The “climate-endangered” species, like the bald eagle, "are projected to lose more than 50 percent of their current range by 2050, with no net gain from range expansion.”

Although only nine birds species have gone extinct in continental North America in modern times, the losses were spectacular and caught the general public by surprise.  This is especially true of the passenger pigeon, which flew in such awesome numbers that no one believed they could become extinct.  But it happened.  On September 1, 1914, the last passenger pigeon, Martha, died at the Cincinnati Zoo, where it was kept as part of an unsuccessful attempt to save the species through a breeding program.

So, it’s appropriate for Ohioans to take the lead in in accepting  Audubon’s challenge to act now to prevent these predictions from being fulfilled.  After all, because Martha died relatively close to Columbus, the National Audubon Society chose the Audubon headquarters in Columbus to be the home of the sculptures of the passenger pigeon and four other extinct birds:  Labrador Duck, the Great Auk, the Heath Hen, and the Carolina Parakeet.  The other North American birds that went extinct since records were kept are:  Bachman’s Warbler, Dusky Seaside Sparrow, Eskimo Curlew, and Ivory-Billed Woodpecker.

Even Chad Robbins , the father of modern ornithology who organized the North American Breeding Survey, told me he never believed that the Kirtland warbler would be so close to extinction in his lifetime.

 I have never seen such an alarming issue of Audubon magazine—All 314 names of the threatened species runs along the top of 57 pages of the 102-page issue.

The Audubon study is undergoing peer review for journal publication.

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