Every February the Audubon Society of the District of Columbia braves cold winds and winter weather to travel to Theodore Roosevelt Island, an almost 90-acre national memorial in the heart of Washington D.C. Covered with forests and hiking trails, the oblong island splits the Potomac River in a hooked meander south of Georgetown. Home to the northern-most Bald Cyprus swamp in North America, the island attracts birds such as White-throated Sparrows and Dark-eyed Juncos over winter. Temperatures are usually in the 40-degree range, and the walking bridge, the island’s only access point for the public, can be slippery with ice and snow.
“Usually there’s snow on the ground, it’s freezing, and we’re the only people there,” says Zachary Slavin, program manager of the Great Backyard Bird Count and a board member of the D.C. Audubon Chapter.
But this year, record-high temperatures in February drew many more outdoors during what’s usually the dead of winter. “This year the parking lot was overflowing with dog walkers and bikers,” Slavin says. There were even people canoeing and paddle boarding in the Potomac, he recalls, when usually the area is devoid of most people. Plants were already blooming, weeks earlier than their normal spring awakening.
The weekend’s high temperatures were not unique to D.C. That weekend, Boston nearly hit 60 degrees, around 20 degrees above the normal average for that time. In D.C., it hit 71 degrees, 23 degrees above the historical average.
And it wasn’t just an occurrence for the GBBC weekend or for only eastern North America, either. This February was the second warmest globally in recorded history, according to NASA’s Goddard Institute for Space Studies. This warmth seems to have, in part, supercharged the turnout; the data this year show a new high in birds seen. But along with this, the numbers show some species in places that they wouldn’t normally be in mid-February, representing earlier migration patterns and overwintering sites farther north than typical for some species.
For the 2017 Great Backyard Bird Count, more than 214,000 people participated around the world, a 25 percent increase from last year and record high. Every year, participation numbers have grown as the program has expanded—more countries join every year. Nearly 300 more species were identified overall this year than last year for a total of 5,940, with 1,559 species identified in North America.
Of the more than 1,500 North American species, this year’s data shows several species migrating north earlier, specifically species that move depending on the weather. Normally, Common Grackles and Red-winged Blackbirds would not begin to migrate from warmer climes until the end of February, with small numbers leaving earlier. This year, participants reported groups of both species as far north as the lower Canadian provinces of Quebec and Ontario. Participants even reported flocks of 20 or 30 in southern New England, suggesting that the birds are making their springtime journey nearly two weeks earlier than previous years. This mirrors reports that spring has sprung ahead of schedule across the United States, with accounts of early spring foliage weeks or even a month early as far north as lower New York state, New Jersey, and Pennsylvania. But conditions have been temperamental.
“A lot of [the birds] are wishing they didn’t come up here this early with the winter weather we’ve seen since,” says Geoff LeBaron, the director of the Christmas Bird Count for the National Audubon Society. LeBaron notes that these species will move according to the weather, though, and are not as connected to place like other migrating birds, such as warblers. Some birds may have moved to adapt to the cold snaps.
Other birds are even showing signs of overwintering further north than they historically would. Again, LeBaron says, these species are not dependent on place, but the temperature. “Why fly to Florida if you can survive just as well in New Jersey?” he says.
According to the GBBC report, one bird showing signs of changing migration patterns is the Tree Swallow. This year, the data showed increased Tree Swallow counts of overwintering birds further north—in coastal areas as far north as Long Island on the East Coast and Vancouver on the west. Historically, on the East Coast, the birds winter south of Virginia and on the West Coast, from central California south. But recently, more have been deciding to stay northward. And those that did migrate are returning earlier this year—2017 produced the first-ever February Tree Swallows in northern Illinois and Quebec province. Usually, Tree Swallows don't migrate until March.
Other species, such as Killdeer and American Woodcocks, also showed earlier northern migration. GBBC leaders credit these early migration and northern wintering numbers to warmer weather on the East Coast and predict that other species such as Eastern Phoebes and Chipping Sparrows will be following soon, taking the journey north earlier than usual.
The 2017 GBBC also produced some rarities that could be linked with warmer weather on the eastern seaboard. Specifically, in a continuing trend from years’ past, Pink-footed Geese have been spotted from Nova Scotia to New Jersey, though they're native across the pond and found in northwestern Europe during the winter. North Americans are sighting these visitors more and more often, perhaps because the birds find our warmer weather conditions to their liking. The species, which breeds in Greenland, was also spotted on the West Coast in British Columbia, Canada, but those birds are assumed to be escapees from a private waterfowl collection.
Overall, the GBBC data shows unusual distributions of waterfowl—rare and common—throughout the country, which the count leaders think is linked with the amount of ice accumulation on lakes. With more open water and warmer weather to choose from, many fowl headed elsewhere. Slavin saw this firsthand around Theodore Roosevelt Island, where the Potomac shoreline usually has pockets of waterfowl easy for counting. This year, he saw fewer ducks and grebes, and when looking at the GBBC data, he saw much higher numbers elsewhere. Red-necked Grebes, for example, had higher counts in the Great Lakes region, and were missing from the D.C. area.
Less ice and snow may have also lowered the number of birds at feeders. According to LeBaron, participants saw lower numbers of bird species that are common at feeders during the winter months—species such as Northern Cardinals, Black-capped Chickadees, and House Finches. GBBC project leaders think this could be a link to earlier spring foliage, or even warm weather causing some food sources (grass seeds, ornamental berries, overwintering insects) to remain over the harsh months. More birds chose those food sources over seed at feeders.
Though Slavin and his Audubon chapter didn’t see the waterfowl and other winter birds they were accustomed to seeing, they observed early migrants like Red-winged Blackbirds and Common Grackles. They even saw a House Wren, a bird pretty easy to identify, says Slavin, “but we had to do a double take because it [was] February.” The bird was the first House Wren of the season to be reported in D.C., when the species usually migrates northward in mid- to late April.
The beautiful weather made for a record-breaking day, but Slavin says that the talk was a bit anxious—a more uneasy appreciation for the warmth. “It was strange,” he says. “We had a lot of conversations about climate change. People were concerned, especially about how the birds will be affected. We were usually bundled up, but now walking around in T-shirts.”
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