Audubon presents dire forecast for many species

White-throated Sparrow

Would you miss the melody of the White-throated Sparrow? The tree-climbing antics of the White-breasted Nuthatch? How about the aquatic grace of the Mallard? 

These are among the birds that may become scarcer—or even disappear—from the Lehigh Valley because their breeding ranges are being reduced or altered due to climate change, according to a report issued yesterday by the National Audubon Society.

The Audubon Birds and Climate Report is the first of its kind to examine how climate change could affect North American birds. According to Audubon scientists, 314 bird species will be in dire straits by the end of the century; 126 species will be endangered before 2080.

"When you realize that only nine bird species have gone extinct in continental North America in modern times, then you see that we're looking at 314 North American bird species at risk by the end of the century—it take's your breath away," said Gary Langham, Audubon's chief scientist.

The report examined the possible futures of 588 bird species. The scientists took 30 years of observations from the Audubon Christmas Bird Count and the North American Breeding Bird Survey as a starting point. Then, using internationally recognized scenarios of greenhouse gas emissions and each bird's ideal climatic range, the scientists forecast how the bird's range would expand, contract or shift at three future time periods—2020, 2050 and 2080.

Some bird species will be able to adapt to the new climatic conditions, but certainly not all. And while many people assume that climate change will simply shift habitats farther north or to higher elevations, breeding ranges for 126 climate-endangered species will see their habitats shrink. Some species, such as the Cerulean Warbler, may have nowhere to go.

"The report is a roadmap, and it's telling us two big things: We have to preserve and protect the places where birds live, and we have to work together to reduce the severity of global warming," said Audubon President and CEO David Yarnold.

For Pennsylvanians, the touchstone is the state's Climate Impacts Assessment study. It finds that the weather will be much hotter—on average, 4.5 to 8 degrees Fahrenheit higher by 2080. As decades pass, we'll see wider swings in precipitation, from prolonged dry spells to rainfalls that are more frequent and more intense. Flooding will become common. Winter will bring more rain than snow. Forested land will decline, and tree species gradually will move northward to avoid the searing summer heat. Trees will become more susceptible to fire, insects and disease. Invasive plant species will thrive. 

Iconic birds are threatened

Ruffed Grouse

Pennsylvania's state bird, the Ruffed Grouse, will see a major upheaval. By the end of the century, you'll have to travel to Canada to see one of these birds because they won't exist anymore in the lower 48 states. The Pennsylvania climate of 2080 will be too hot and too wet for the habitat on which the grouse depends. 

While we're mentioning symbols, consider the fate of the Bald Eagle. It will have only 26 percent of its current breeding range remaining by 2080.  Audubon scientists say the eagle could escape the loss of habitat by relocating farther north. "Its success isn't guaranteed in the new areas—the majestic raptor will still have to find suitable food and nesting habitat," the scientists say. But will the national bird of the United States become primarily a Canadian bird?

Cool-weather species face problems. The White-throated Sparrow, a familiar songster in the Lehigh Valley during the winter, will move ever northward, deeper into Canada, to breed. They require dense ground vegetation—shrubs, grasses and ferns—for nesting. As a warmer climate pushes boreal forests farther north, the sparrows will have to count on Arctic tundra being replaced by brushy vegetation and coniferous trees.

The White-breasted Nuthatch will remain in the Lehigh Valley but at reduced numbers, according to the Audubon report. Again, the warmer climate will push many nuthatches northward, well into Canada, for breeding purposes. About one-sixth of the birds' current habitat will be lost. One of the problems in forecasting the future of the White-breasted Nuthatch in a given area is the discovery that the bird may actually be two, three or even four distinct species. Conservation biologists are studying the issue; they will have to monitor geographically distinct populations because some nuthatches may prove hardier than others.

Also on the Audubon Society's list is the Red-breasted Nuthatch. This species is content living in any kind of conifer. They'll even inhabit Christmas tree farms. The main question for the bird's future population is how extensive the conifer forests will be in Pennsylvania as the climate continues to changes. 

Ducks will be seriously affected

Male Mallard

The Mallard and many other ducks that visit our ponds and marshes are in serious trouble, according to the Audubon report. By 2080 the Mallard's range will shift northward during the summer breeding season, with only one-quarter of its current range remaining. By the end of the century, the bird will no longer be breeding in the lower 48 states. 

The Gadwall, a less showy but equally important duck, is in worse shape. More than 90 percent of its current habitat will be lost by 2080. "If there's any hope for the Gadwall, it's that this is a numerous and widespread species, with many thousands, if not millions, also living in the Old World," the Audubon report says. Ironically the duck has being seeing increases in population since the 1980s.

Likewise the Ring-necked Duck, with its faint iridescent maroon ring around its neck and bold white ring around its blue beak, will face major challenges. Its breeding range will decline by about 90 percent, forcing the bird northward, away from Pennsylvania.

Most backyard birds will remain

Some species seen in our backyards also will be affected. Cardinals, blue jays, goldfinches, robins, House Sparrows, starlings and others will remain. The Purple Finch is another story.

The Purple Finch has been losing ground to its recently introduced cousin, the House Finch, since the 1940s. A changing climate poses new difficulties. The Purple Finch will need to shift its summer and winter ranges northward. Our great-grandchildren may never see the bird in Pennsylvania. One bright spot: The Purple Finch, if it is lucky, could colonize Alaska.

The Hairy Woodpecker's fate is unclear. This nonmigratory bird could face loss of climate-suitable range during the breeding season. Most of its habitat—forest land—will be transformed by a warming climate.

Baltimore Oriole

The Baltimore Oriole, the namesake of a baseball team, could strike out, at least as far as our home stadium is concerned. The Audubon report says that by 2080, the Baltimore Oriole may no longer nest in the Mid-Atlantic region, instead shifting northward to follow the climate conditions it requires. 

The Lehigh Valley is treated to visits by Pine Siskins each winter. Those sightings will become less common as the century unrolls. Its current breeding range will decrease by about one-third by 2080 and the bird will have to move farther north to breed and winter.

The American Kestrel, a raptor seen in the Lehigh Valley, is in serious trouble. By the end of the century it will vanish from our region, according to the Audubon study. The amount of suitable breeding climate for this colorful falcon is shifting northward. The bird already is in decline throughout the Northeast and New England. Climate change will cause that pace to accelerate, the study says.

Other Pennsylvania birds face challenges

Double-crested Cormorant

The Double-crested Cormorant may be able to accommodate the changing climate—but there are several ifs. The species has increased substantially in some parts of North America, thanks to reduced use of pesticides, including DDT. Because the bird is migratory, it may gain an advantage as its summer breeding range expands. But scientists are not sure how the changing climate will affect the birds' winter range in Mexico, Cuba and the southern United States.

Already in decline, the American Black Duck faces both challenges and opportunities. This close relative of the Mallard will see new areas of potentially suitable climate in Canada during breeding season. However it probably will yield ground in the winter (the period when it most often is seen in the Lehigh Valley).

You may see Ring-billed Gulls dining in the parking lots outside fast food restaurants. Their future is fairly bright. They may lose one-third of their current summertime range by 2080, but will find new settings to replace it, according to the Audubon report. Scientists are counting on the gulls' resourcefulness and adaptability to get through the transition  In a surprising twist, the Herring Gull is expected to lose 20 percent of its summertime territory; prospects for the winter look promising. The Herring Gull also is adaptable. It, too, will rely on garbage landfills, shopping malls and coastlines for food sources.

Wood Thrush

Four woodland species face significant loss of breeding habitat in Pennsylvania. The Audubon report forecasts the Brown Creeper will lose one-third of its breeding grounds; the Hermit Thrush, about one-quarter. The Hermit Thrush had an advantage: It has a more extensive range. 

The Wood Thrush, having battled forest fragmentation, nest predation and the intrusion of cowbirds, now faces climate change. It will lose nearly one-third its breeding range by 2080. The Ovenbird seems destined to vacate the state. Currently found in eastern and western Pennsylvania, strutting like a tiny chicken, this forest bird will see its breeding range shift by two-thirds, forcing it well into Canada.

The Veery, a thrush species, prefers low-elevation broadleaf forests that are a bit wet. It finds central and western Pennsylvania a great place to live. But the changing climate means moving day for the Veery. It will have to withdraw to Canada—and expand westward to Alaska—to find enough forested land. It also will have to depend on broadleaf trees making inroads on existing Canadian conifers. 

The Tree Swallow is a hardy species. The problem it faces is not so much with summertime breeding but wintertime habitat. Right now Tree Swallows winter along the Gulf coast. In the future this area could become inhospitable, costing them 92 percent of their winter territory. They will have to adapt by moving farther north and farther inland. Likewise they will need to breed farther north. That will require more nesting sites than exist currently; the Audubon Society says the bird could be helped with human-supplied nesting boxes.

Male Scarlet Tanager

The brilliant red of the male Scarlet Tanager may become a thing of the past by 2080 in Pennsylvania. The study projects a 93 percent shift in the bird's breeding population, moving it well into eastern Canada. It currently is a common summer resident in the state. The Scarlet Tanager could find suitable climate-conducive space in Alberta, Manitoba and Saskatchewan but the Western Tanager may put up stiff resistance. The betting is that the Western Tanager will win. Scarlet Tanagers winter in South America.

The Yellow-throated Vireo nests and breeds in hardwood forests in the eastern United States. It spends its winters in Cuba, the Bahamas and northern Mexico. With climate change, this vireo may spend its time exclusively in the United States because weather in the South in 2080 will mimic today's Caribbean. The outlook for breeding is less certain. The current territory may contract or the species may drift northward.

The Yellow-bellied Sapsucker has seen its range expand in Pennsylvania and New York as forests regenerated in recent decades. That trend will reverse as the climate changes, Audubon scientists forecast. The bird will lose nearly one-third of its climate-suitable breeding grounds. (In the Lehigh Valley, the Yellow-bellied Sapsucker is seen mostly during winter months.)

A common but hard-to-see Eastern wetland species, the Swamp Sparrow will need to shift its breeding range northward and westward by about two-thirds. Resident species along the New England coast will be harmed by a decrease in salt marshes due to rising sea levels.

The Northern Harrier, often seen coursing over low grasslands in search of prey, will lose about one-third of its summer breeding range. The harrier will have to undergo "a significant shift northward" to find climate-suitable breeding territory, the report says.

The Common Raven will lose one-third of its winter range and one-sixth of its summer range but the bird is extraordinarily adaptable, becoming increasingly at home in cities.

Saw-whet Owl

On the other hand, the Saw-whet Owl population could decline precipitously. Audubon scientists forecast the owl will lose nearly 95 percent of its suitable wintertime climate space by 2080. The scientists caution, however, that little is known about the winter behavior of the diminutive owl and the prognosis could be off by quite a bit. (The owl is seen at all seasons in the Lehigh Valley but only rarely.)

The Willow Flycatcher is widely distributed in Pennsylvania. But by the end of the century the eastern population will be Canadian. Audubon projects a modest expansion northward in the breeding territory but cautions that not all populations may adapt. 

Say goodbye to the Bobolink as a resident of Pennsylvania. Only one-fifth of the bird's current range will remain by 2080; if the Bobolink can find suitable grasslands in a swath from northern Labrador to Alberta, it will thrive.

Prospects are mixed for visiting migrants

The eerie sounds of the Common Loon on northern lakes will become less audible because there will be fewer of them. By 2080 they will have lost about half of their breeding territory. The birds, which currently pass through the Lehigh Valley in spring and fall, will have to move elsewhere to survive.

Common Loon

One of the two warblers on the Aubudon's list of climate-challenged birds, the Black-and-white Warbler, will have to find new forested breeding territory farther north. The Chestnut-sided Warbler is in better shape; its summer range is more stable.

The Golden-crowned Kinglet, one of the smaller North American birds, is a winter resident of Pennsylvania. To maintain its breeding range it will have to shift northward, penetrating even deeper into Canada. Its future depends on two factors: extensive conifer forests for breeding and plentiful tiny invertebrates in winter.

A migratory visitor to our area, the Horned Grebe "may be in grave danger," the Audubon report says. It is expected to lose more than 80 percent of its breeding territory by 2080.

Male Hooded Merganser

The Common Merganser, which is not all that common in the Lehigh Valley, will be seen even less frequently. It will move northward, away from a warming Pennsylvania, and head deeper into the Nunavut territory of Canada for breeding. In contrast, the Hooded Merganser is expected to nearly double its summer breeding range by 2080. Its winter range will decrease slightly. "By that measure, the Hooded Merganser looks like it could be one of the winners as the planet warms due to climate change," the Audubon report says.

The Goldeneye and the Bufflehead, closely related diving ducks, face the same obstacle: They nest exclusively in wood cavities in boreal forests, those with a mix of trees and wetlands. Everything depends on the ability of boreal forests to withstand a warmer climate.

The American Wigeon, a grazer along ponds fringed by grasses and lawns, will lose 26 percent of its breeding area. It will be one of several migratory waterfowl that will begin wintering farther north as the ice cap retreats toward the North Pole. (The wigeon is seen passing through the Lehigh Valley during its migration southward.)

Male Redhead

The Redhead, a diving duck, is seen infrequently in Pennsylvania. Its main breeding range, on the northern prairies, is expected to decline by 79 percent by 2080, with little expansion into new territories.

The Greater Scaup, which winters along the Atlantic coast but is rarely seen as far inland as the Lehigh Valley, will lose some breeding area by 2080 but has room to spare in the Canadian High Arctic. Audubon researchers are less certain about prospects for the Lesser Scaup. It has the advantage of being able to claim further breeding areas in the Canadian Arctic but the reliability of its wintering grounds is less clear.

Canada's moist, broad-leafed forests are the summer homes of the American Redstart; it may capitalize from climate change if suitable plants and insects reach deeper into the Arctic. (The bird is seen in Pennsylvania during its migration to Central America and the Caribbean.)

Common Redpoll

Another denizen of the Canadian north, the Common Redpoll, will lose a good deal of its breeding range. The report estimates that only 23 percent will be stable; things look better for its winter range, which currently includes parts of Pennsylvania.

The diminutive Least Flycatcher will lose 40 percent of its current breeding range, but its the changing climate may allow it to spread all the way to the Arctic Coastal Plain. (When the bird is seen at all in the Lehigh Valley, it is during its migration.)

(The Bird House wishes to thank the authors of "Birds of the Lehigh Valley and Vicinity" for their expert information on bird species found locally. The book, which is published by the Lehigh Valley Audubon Society, is an incredibly valuable resource for anyone who loves birds.)