Some of Maine’s most iconic birds, including the boreal chickadee, the common loon and the ruffed grouse, would vanish from the state entirely by the end of the century if climate change continues at the current pace, according to a report released Thursday by the National Audubon Society.

Loss of habitat or food, harsh weather conditions and rising sea levels are among the effects of climate change that would force Maine birds to move farther north, reduce the size of their range and shrink their population, said Jeff Wells, vice president of Boreal Conservation at National Audubon.

Audubon scientists used data gathered by biologists and birders across North America to create various models showing the effects climate change could have on birds in the next 80 years. In the report’s best-case scenario, which relies on efforts to mitigate climate change, just over a third of 187 bird species in Maine would become threatened. In the worst case, in which nothing is done, that number would double.

The full report showed that 63 percent of 604 species in North America would become vulnerable under a temperature rise of 3 degrees Celsius, compared to 54 percent if temperatures rise 2 degrees and 47 percent they go up 1.5 degrees.

Maine would be one of the worst-hit states under the worst-case scenario because its northerly climate has a wide diversity of bird habitat that captures breeding birds that migrate south in the winter and those that remain, like the black-capped chickadee and boreal chickadee, Wells said.

“We have overlapping climate-change-induced threats: heavy rains, weather that is prone to fire risk, sea levels rising,” Wells said. “We have a tendency to have all of those things where we are.”

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Brad Lyon, a research professor at the Climate Change Institute at the University of Maine in Orono, said it’s conceivable that by 2100 the average global temperature will increase 3 degrees Celsius, or 5.4 Fahrenheit – the figure on which the Audubon report’s worst-case scenario is based. The best-case scenario assumes an increase of 1.5 degrees Celsius, which Audubon scientists say could happen as early as 2050 if carbon emissions are not reduced.

“Based on the trajectory at the moment in terms of emissions, that’s very reasonable to think,” Lyon said. “We expect the global average to be somewhere between a 1.5- and a 4.5-degree increase by the end of the century.”

The ruffed grouse is one of 106 breeding bird species in Maine that will be threatened if global temperatures rise – as projected at current levels – as much as 3 degrees Celsius by 2100, according to a report by the National Audubon Society. Matt Stirn Photo

The Audubon report comes a month after a team of ornithologists in Canada and the United States released a study that showed 3 billion birds representing hundreds of species have perished over the past 50 years as a result of loss of habitat, pesticides, light pollution and other effects of climate change.

Noah Perlut, a professor of ornithology at the University of New England, said the timing of National Audubon’s report is significant – coming a few weeks after the other scientific study.

“Any ornithologist that read that paper on the other big population model was not surprised in any way, shape or form,” Perlut said. “But it was amazing the press it got. It was amazing to me the people I heard from who don’t think about birds, and they thought it was terrible. I definitely think the context of the two studies together are a powerful story.”

The Audubon report only looked at species for which there were good data sets, with much of the data coming from birders who record on the e-bird website managed by the Cornell Lab of Ornithology. Based on 140 million bird records from more than 70 data sources, the report mapped the future range of birds based on climate change exposure and the ability to adapt.

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The report showed 106 of 187 breeding species in Maine facing threats, under the worst-case scenario and 64 species in the best case. Wells said Maine is home to a total of 285 regularly occurring breeding, migrant and wintering species of birds.

Wells added that the worst-case scenario for birds also is a bad scenario for people.

“Birds are the indicators of what happens to us in the future,” Wells said. “If sea levels rise it not only wipes out the nests of breeding seabirds, it washes away condos and homes. It’s easy to see this as something bird lovers care about – but it’s going to hit all of us.”

The boreal chickadee will be extirpated from Maine if global temperatures continue to rise as a result of climate change, the National Audubon Society reported Thursday. Photo courtesy of Jeff Wells

The different bird species considered by scientists face varying degrees of threats in the three models, depending on the species’ range and habitat, and the three different scenarios of global temperature change.

The boreal chickadee, for example, would colonize new parts of Canada and lose about 50 percent of its global range, including all of Maine, in the report’s worst-case scenario, Wells said.

Other species the report predicts would disappear from Maine are the white-throated sparrow, the dark-eyed junko, the purple finch and the black-throated green warbler.

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Maine Audubon’s Outreach and Network Manager Nick Lund said some seabirds, like the puffin, that were not among the species included in the report also face grave threats from a warming Gulf of Maine due to climate change – and they already are a great concern to Maine Audubon biologists.

“We know already the puffin is being impacted because its primary food sources are not as plentiful because of climate change,” Lund said. “If these birds have to find different nesting colonies closer to food sources, we’re not sure how that will play out.”

Though reducing emissions from vehicles and power plants is a major goal outlined in the report, Wells said conserving land also is key, not only to maintain more bird habitat but also to provide trees and plants that can absorb carbon and help mitigate greenhouse gases.

Lund said Maine Audubon has been working for years to help reverse the effects of climate change by promoting land conservation and working with landowners and foresters to maintain wildlife habitat, among other things.

“This report doesn’t change anything we’re doing,” Lund said. “It tracks right in line with the work we’re doing to stem climate change and minimize its impact.”

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