Each September, 12-year-old "Julia" flies 4,200 miles from her home in northern Alaska to spend winters in Annapolis, Maryland.
Traveling in a "V" formation, she and her migrating companions take several months to make the cross-country journey – stopping at waterways along the route to rest and eat.
By December, they join hundreds of other tundra swans, who feed on aquatic plants in the Chesapeake Bay until March, when their return trip begins.
Named by Annapolis residents, Julia is monitored by researchers by a collar with her scientific name, "T186."
Craig Ely, a research wildlife biologist with the U.S. Geological Survey's Alaska Science Center, said T186 was banded July 27, 2006, in the Colville River Delta – one of Alaska's five tundra swan breeding areas.
Scientists keep track of Julia with the help of observers notifying USGS when they see her. Tundra swans are flightless briefly during the summer as they shed their flight feathers (or molt) and grow new ones, so Alaska researchers were able to recapture Julia in 2009 while testing wild birds for avian flu. (She was fine.)
Many birds migrate, but some tundra swans spend most of the year traveling to and from breeding grounds. Those from Julia's home travel the farthest, wintering in Maryland, Virginia and North Carolina. Those from Alaska's western shore winter in Washington state, Oregon and Northern California. Tundras from Alaska's lower peninsula don't migrate at all.
"It's something in their DNA," Ely said, explaining the different routes. He and other researchers wondered whether distance traveled affected swan survival and breeding rates, but in 2016, they concluded it wasn't a major factor.
North America's two native swan species have white bodies, with black bills and feet. Adult tundras weigh 15 to 17 pounds and have 6- to 7-foot wingspans.
The larger trumpeter swans, found mostly in the Midwest, occasionally show up in the Mid-Atlantic.
You can easily tell these species apart by their vocalizations. Trumpeters, as their name suggests, sound as if they're tooting horns loudly. Lee Hendrik, 24, a park naturalist at Mason Neck State Park in Lorton, Virginia, said tundra swans have soothing three-syllable, high-pitched calls.
Also, look at the lores – the area below the eyes and above the bill. U.S. tundra swans have small yellow spots on their lores, while those of trumpeters are usually all black. The young of both – called cygnets – have grayish bodies and some pink on their bills.
Swans mate for life and can breed at 3 to 4 years old. Cygnets stay with their parents for the first year to learn the migration route. Julia doesn't appear to have a mate yet, but wild swans can live for more than 20 years.
"Tundra swans are so tied into water resources that changes in climate and wetlands can really affect them," Ely said. "It's one demonstration of how wetland conservation is important." Still, they have proved to be very adaptable to changing climate conditions, he said.
As to Julia's continued appearances in Maryland, "she has good habits," Ely said. "Whatever she's doing, she's doing it well."