Bald eagles are among the iconic birds that may be impacted by a changing climate in ways that are still unknown.
Dozens of different birds—Northern pintails, wild turkeys, Franklin's gulls, Steller's jays, and cedar waxwings, just to name a few—make homes for themselves in Yellowstone National Park during at least part of the year. Millions of birdwatchers make their way here and to national parks all over the country each year to see them.
Collectively, birdwatchers spend some $107 billion dollars annually in the U.S. But if climate change continues uninterrupted, duck enthusiasts may have to travel elsewhere if they wish to catch a glimpse of a Northern pintail. By 2050, this species could no longer find suitable habitat in Yellowstone. On the other hand, avian enthusiasts could begin to see the Western scrub jay showing up there, at least in the winter.
Because they can move around so easily on their wings, birds are often considered indicator species. When the climate begins to change, birds are often the first to display a response that we notice. Recent assessments of the impacts of climate change on birds in the U.S. and Canada suggest that one in five species are highly vulnerable to climate change; that is, they are so particular about the temperatures they can tolerate that they may disappear entirely from some parts of their range. But if they're lucky, they can expand elsewhere into newly suitable habitat.
A team of researchers from the National Audubon Society and the U.S. National Park Service reported Wednesday in the journal PLOS ONE that 60 percent of U.S. national parks could become more hospitable for birds overall by the middle of the century—if climate change continues apace. In other words, the number of potential new colonizations would exceed the number of potential local extirpations for roughly three out of every five national parks. That's based on an assessment of 513 species across 274 parks.
"You often hear of climate change being all doom and gloom, but one of the findings is that in winter especially, parks are going to become more important sanctuaries for birds," says Audubon Society avian biologist Joanna Wu, who led the study.
Some birds may even stop migrating if winters are mild enough that they can tolerate local conditions, says Wu.
The Power of Parks
The new data underscore just how critical it is to protect the national park system—often referred to as "America's Best Idea"—to ensure a bright future for as many North American birds as possible, the researchers say.
But they also suggest that the avian communities of the future could look dramatically different from the ones we know today. And it is at best unclear what ecological consequences would emerge if Wu's predictions come true.
"We're saying that climate will become suitable, but the species' dispersal capacity, ability to find resources and food and places to raise their chicks, those are all big question marks," she says.
Indeed, says McGill University avian biologist Barbara Frei, who was not involved in the study, "if the birds can adapt to climate change by moving north, but the trees they depend on can't, where will they nest?"
THE YEAR OF THE BIRD
In 1918 Congress passed the Migratory Bird Treaty Act to protect birds from wanton killing. To celebrate the centennial, National Geographic is partnering with the National Audubon Society, BirdLife International, and the Cornell Lab of Ornithology to declare 2018 the Year of the Bird. Sign the pledge to find out this month's action and share your actions using #BirdYourWorld to increase your impact.
Given how different each park is from the others, its impossible to derive a single, simple set of recommendations for the park service overall.
Wu and her colleagues write that parks that don't anticipate tremendous changes in their avian communities might prioritize habitat restoration and invasive species removal, strategies to help those birds that currently utilize those parks remain resilient in the face of climate change. Those parks that can expect high levels of avian turnover, on the other hand, may want to consider finding ways to help ease the transition for new arrivals, like increasing the amount of overall habitat available.
But the truth is that while birdier parks may seem like good news, Wu's predictions reflect the consequences of continuing along our current climate path, the status quo. They do not predict an idealized, increasingly feathered future.
As a resident of San Francisco, Wu is both excited and concerned by the idea of being able to see cactus wrens, Gambel's quail, and Gila woodpeckers—all commonly associated with arid habitats—showing up nearby in Yosemite National Park.
"It's simultaneously interesting, and potentially telling, of the future climate there," she says.