Many state birds may flee their home states as the world warms

WASHINGTON - Each state in America has an official state bird, usually an iconic species that helps define the landscape. Minnesota chose the common loon, whose haunting wails echo across the state’s northern lakes each summer. Georgia picked the brown thrasher, a fiercely territorial bird with a repertoire of more than 1,000 song types.

But as the planet warms and birds across the country relocate to escape the heat, at least eight states could see their state birds largely or entirely disappear from within their borders during the summer, according to a new study.

The research, released Thursday by the National Audubon Society, projects that hundreds of bird species across North America are likely to drastically shift their ranges in the decades ahead in response to rising temperatures and other threats from climate change.

The report raises the prospect that many bird species could struggle to cope as warming forces them into unfamiliar territory or shrinks their existing habitats. And it illustrates how thoroughly the avian world as we know it may be remapped if humans continue pumping greenhouse gas emissions into the atmosphere.

If global temperatures rise a plausible 3 degrees Celsius above preindustrial levels this century, Minnesota will no longer enjoy the local climate conditions that loons are accustomed to as they arrive each summer to breed and hunt for food, the study found. As a result, the birds may bypass the state altogether and head farther north.

The same goes for other state birds, including the northern flicker in Alabama - known locally as the yellowhammer - as well as the brown thrasher in Georgia, the purple finch in New Hampshire, the hermit thrush in Vermont and the goldfinch in Iowa and New Jersey. Those birds are projected to lose virtually all of their summer ranges within those states at 3 degrees of global warming.

The California quail, often seen strutting around the state’s suburbs and parks, could lose 87% of its winter range in California.

And the ruffed grouse, the official state game bird in Pennsylvania and one that is popular with hunters, could lose its entire summer and winter ranges in the state, the study found.

“It’s one way we’ll see the effects of climate change right in our own backyards,” said David Yarnold, the president of the National Audubon Society. “If you’ve ever been around a lake in the upper United States, you can probably hear the sound of a loon in your head. It’s hard to imagine a Minnesota summer without them. It’s hard to imagine a New Jersey summer without goldfinches.”

To conduct the study, Audubon’s scientists using data from millions of bird observations to map the current ranges and habitats of 604 bird species across North America.

The scientists then used climate models to estimate the birds’ future ranges under warming of 1.5 degrees, 2 degrees and 3 degrees Celsius above preindustrial climate levels. The expectation was that many birds will try to move to keep up with shifts in temperature, rainfall and vegetation.

Many species could face major upheaval.

The report has labeled 389 of the species studied as “vulnerable” to 3 degrees Celsius of warming. That means the birds are projected to lose a significant portion of their current range and may have relatively limited opportunities to move elsewhere. Examples include the lark bunting, Colorado’s state bird, and the wood thrush, a migratory bird that breeds in Eastern forests.

The report also mapped out which bird species are likely to face additional dangers from climate change, such as increased springtime heat, fiercer wildfires or rising ocean levels. For instance, the piping plover, which nests in sandy areas along the Atlantic coast, is expected to see its habitat encroached by the rising seas.

Outside experts who reviewed the study called its methods to project shifting bird ranges and other climate threats reasonable. But they cautioned that it can be extremely difficult to predict how many bird species might be able to adapt to hotter climates and new environments - and, conversely, how many birds might face increased extinction risk as a result.

“There’s a lot we don’t know about how certain species might adapt to novel climate conditions,” said Benjamin Zuckerberg, an associate professor in the Department of Forest and Wildlife Ecology at the University of Wisconsin-Madison. “We might see bird species shifting their nesting times or changing their diet.”

But, he added, “there is a real concern that the rate of climate change is going to be beyond the ability of many species to adapt.”

The Audubon report is a much more detailed update of a study the group published in 2014 on how climate change might disrupt bird populations.

And it comes on the heels of a recent paper in the journal Science estimating that the total number of birds in the United States and Canada has declined by 29% since 1970, with 2.9 billion fewer birds in the skies today.

Much of that decline, experts say, was likely caused by habitat loss or pesticide use, not climate change.

But there are some signs that global warming is now putting additional pressure on birds.

In a 2012 study, scientists concluded that climate change had likely contributed to the decline of the once-common rusty blackbird, which has seen its range in Maine retract northward as temperatures have risen.