The fate of a drab, little bird that roosts in the Green Mountains could have far-reaching implications on the future of the economy and endangered species in the United States.
The federal government has begun the process to decide whether to list the Bicknell’s thrush, a Northeastern mountain songbird, as endangered. The U.S. Fish and Wildlife Service is reviewing scientific material on the thrush, and the initial public comment period on the thrush’s status ended Oct. 31. The Vermont-based Center for Biological Diversity first petitioned the federal government to list the bird as endangered.
But the threats the thrush faces will prove difficult to overcome, even with an endangered designation. Conservationists warn the bird faces extinction unless the U.S. government can slow climate change and greatly curb mercury emissions from Midwestern power plants. A recovery plan for the bird may require a fundamental reworking of a fossil fuel-based economy. Environmentalists argue that the federal government is obligated to undertake such actions under the provisions of the Endangered Species Act.
The Bicknell’s thrush has been faring so poorly because of the shrinking of its already scarce habitat, said Mollie Matteson, conservation advocate with the Center for Biological Diversity. The bird generally favors high-elevation nesting grounds on the timberlines of mountain ranges in the Northeastern United States, including mountains in Bennington and Rutland counties. And even there it only finds a sliver of land, with just the right mix of balsam firs, suitable for nesting.
But that ideal habitat is shrinking dramatically because of climate change, Matteson said. Even if the climate warms 2 degrees, the center estimates, the thrush’s habitat could shrink as much as 66 percent. As the New England climate warms, environmentalists warn that hardwoods will overtake the firs on the alpine timberline, displacing the Bicknell’s thrush.
“It’s literally going to be pushed right off the mountain,” Matteson said.
Climate change won’t just affect the birds in the summer. The thrush overwinters in tropical Caribbean forests, and climate change models predict those forests are going to dry in the coming years. That habitat is already facing degradation because of deforestation and development in Haiti and the Dominican Republic, Matteson said.
“Its wintering habitat is even more constrained than its breeding habitat,” she said.
The Bicknell’s thrush population is also most likely faring poorly because of power plant emissions from the Midwest, said Jim Shallow, conservation and policy director for Audubon Vermont. Recent blood samples of the birds show elevated levels of mercury, which could affect the reproductive health of the species, he said. To save the bird, the federal government will need either to phase out coal power plants or install more scrubbing technology that would curb emissions. Either solution would be an expensive proposition, but Shallow argues they would be worth it because mercury emissions impact all species.
“There would be human benefits, as well,” Shallow said.
Few expect the process to evaluate the Bicknell’s thrush to go quickly, and Shallow warns it could stretch on for decades. One hurdle is that little is really known about the bird. While first discovered in the late 19th century, it was long considered a subspecies of the gray-cheeked thrush. Genetic testing finally confirmed the bird was a unique species in 1995. Scientists have long known the bird was in trouble, but they have needed to learn more about the bird to petition the government to protect it.
“We need to have a better handle on the life cycle dynamics for the bird,” Shallow said.
The process to protect the thrush also will move slowly because of what is expected to be a monumental legal fight. An endangered species listing most likely will mean environmentalists will need to sue to compel the U.S. government to tighten regulations on greenhouse gas emissions in general, and mercury emissions, in particular. If recent history is any indication, such a call would be vigorously opposed by both power plant operators and the federal government for the overwhelming costs involved, said Matteson.
“What needs to be done to save the species is enormous,” said Matteson.
The federal government so far has resisted arguments that it must regulate greenhouse gas emissions because of the Endangered Species Act. The Obama administration angered environmentalists earlier this year when it refused to incorporate greenhouse gas standards into a proposal to protect the endangered polar bear, and the Center for Biological Diversity previously sued the government for delaying the process to list two threatened Arctic seal species as endangered because the seals’ main threat would be climate change.
While Matteson believes the thrush is another species that can only be saved if climate change is addressed, not everyone is so sure. Vermont Fish and Wildlife coordinator Steve Parren believes the argument that the birds will lose their timberline habitat due to climate change is a bit of a stretch. Wind shear is just as important a factor as temperature to block hardwoods from overtaking firs on the ridgeline, he said.
While Parren understands why environmentalists are focusing on the thrush to spark the conversation about climate change, he says the same case could be made for any number of animals. Ultimately, environmental regulators are going to have a hard time mitigating climate change for all species, he said.
“It’s going to be fascinating in a horrible way,” Parren said.
