As the days get longer, spring approaches. Before winter ends, though, it’s worth taking note of some infrequently seen avian visitors to Maryland this season – trumpeter swans.
With a wingspan up to 7 feet and a standing height of about 4 feet, the trumpeter swan (Cygnus buccinator) is the largest waterfowl in North America. So named because of their deep, sonorous bugling, trumpeters aren’t a common sight around the Chesapeake Bay. But several have been reported since December in and around the Patuxent Research Refuge between Washington, DC, and Baltimore. Multiple birds have also been sighted as recently as this week in southern Anne Arundel County.
“There are some reports, sightings, every year,” said Bill Harvey, game bird section leader of the Wildlife and Heritage Service of the Maryland Department of Natural Resources. “But there are certainly not very many in the state at any one time.”
It’s not clear if the number of trumpeter swans sighted this winter has been typical, but birders say there’s been an uptick in reports over the last decade.
According to the Maryland Biodiversity Project, trumpeter swans are “rare but regular visitors” to the state. They once nested over most of North America, but their numbers dwindled through the 19th century as they were hunted for their feathers, meat and skin. By the 1930s, fewer than 100 were left south of Canada. A ban on hunting them, combined with other conservation efforts, has helped to bring them back in parts of the Northwest, and they’ve been successfully reintroduced in Ontario, Canada and in some Midwest states.
“In the early 80s,” Harvey said, “they started to reintroduce trumpeters, mostly in Ontario, and there’s been a number of marked birds from Ontario showing up here – but none nesting.”
Some trumpeters do nest in New York, he added, but any seen farther south are likely just waiting out the winter before heading back north.
In the 1990s, the late zoologist Bill Sladen tried to train trumpeters to migrate from New York south to Maryland using an ultralight aircraft. But he gave it up after several years, saying it was too expensive as well as dangerous to the swans as well as the ultralight pilots.
Tundra swans, North America’s other native swan species, are more commonly seen around the Bay. They breed in the Arctic north of Canada and Alaska and regularly migrate south in the fall. Mute swans, a nonnative species imported from Europe, were once common, year-round denizens of the region, but their numbers have been decimated by a concerted state campaign to addle, or oil, their eggs. Mute swans were deemed invasive because they feed on recovering Bay grasses and attack native shorebirds.
All three species are big and white, though mute swans have an orange beak that makes them relatively easy to identify. It’s more difficult to tell trumpeters from tundras – both have black beaks — but trumpeters are generally larger, and tundras often have a distinctive yellow spot at the base of their beaks. Some trumpeter swans have been banded, making them easy to identify. But the surest way to identify a non-banded trumpeter is by its vocalization – a deep, distinctive “oh-OH,” which is lower pitched than a tundra swan call.
Greg Crites, a Patuxent Research Refuge volunteer, wrote in an email that his first sighting of trumpeters this winter occurred in December, when he saw and photographed four on a pond in the refuge’s Central Tract, which is closed to the public. He photographed one again in late February and again at the beginning of March.
“I’ve seen a lone Trumpeter on all three of the (refuge’s) tracts the last few days,” Crites said. His latest sighting was on March 9 on Lake Redington, by the National Wildlife Visitors Center on the South Tract.
Sandy Spencer, supervisory wildlife biologist at Patuxent, wrote in an email that she saw a pair in early March on Blue Heron Pond in the refuge’s North Tract and a lone trumpeter on the Central Tract. The refuge’s North and South tracts are open to the public.
Birders also posted reports online on March 12 of as many as seven trumpeter swans in southern Anne Arundel County near the Smithsonian Environmental Research Center in Edgewater. Others reported seeing a lone trumpeter at Lake Elkhorn in Columbia.
“When they show up, they’re usually there for weeks and months,” Harvey noted.
Indeed, birders say, some immature trumpeters have been known to remain in the area year-round before flying back north after a few years when they have reached breeding age.
There’s no official tally of trumpeter swans in the Bay region. While biologists with the DNR and U.S. Fish and Wildlife Service conduct an aerial waterfowl survey every winter, Harvey said it’s virtually impossible from a plane to distinguish a trumpeter from a tundra swan.
Birders say that, because it’s difficult to positively identify unbanded trumpeters, some reported sightings weren’t credited in the past. In recent years, though, the number of trumpeter sightings filed with eBird, the online citizen science monitoring project run by the Cornell Lab of Ornithology, has been trending upward.
Trumpeter sightings also have been reported in neighboring Bay watershed states. In mid-March, a birder reported spying 10 trumpeters – some banded – at the Airlie Conference Center in Fauquier County, VA, where Bill Sladen based his swan migration effort. A pair of trumpeters also was photographed recently by a stormwater pond in Loudoun County, VA, and another pair was spotted in February along the Heritage Rail Trail near York, PA.
“Their populations are doing well,” Maryland birder Tyler Bell wrote in an email, “and it's showing.”