Biologists say hundreds of trumpeter swans will soon return to the greater Yellowstone area, and the Wyoming Game and Fish Department is asking Jackson Hole residents to keep an eye out for the large, white waterfowl.

Each year, thousands of trumpeter swans migrate south from interior Canada to winter in the greater Yellowstone area. Three to seven hundred will winter in western Wyoming, along with the approximately 100 resident swans that live here year round. The birds are the largest waterfowl in North America.

Wyoming Game and Fish nongame biologist Susan Patla said people can help researchers monitor the swans by looking for colored neck or leg bands.

“We rely heavily on reports from the public, particularly bird watchers and waterfowl hunters,” she said in a statement. “It helps that these birds are so visible, so we’ve gotten some great observations from people in the past. It’s very valuable data to us, and we really appreciate it.”

Patla said neck collars are in a variety of colors, including green, blue and red, and they typically have a unique combination of letters and/or numbers on them, which provides a way of identifying individual birds. A keen observer with a spotting scope may also be able to see colored, numbered leg bands, as well.

From collar information, biologists can determine migration patterns, important habitat areas and life spans.

Intermixed with the trumpeter flocks may be their close relative, the tundra swan. This slightly smaller species nests far north in arctic wetlands and most will continue to pass through the state to winter farther south.

Patla encouraged people to enjoy swan viewing but cautioned observers not to disturb swans because intrusive actions could flush them away from important feeding and resting sites. If swans start to head-bob and vocalize, it is best to draw back before they are forced to fly, she said. Controlling dogs at swan wintering sites is also important.

One of the best places to see, hear and photograph swans close up is at the Flat Creek overlook at the National Elk Refuge just north of Jackson. Numbers typically peak in November and then drop off as the marsh freezes up.

“Hopefully, people will have a chance to get out and enjoy the swans while they’re here,” Patla said. “Viewing opportunities like this are not available many other places in the country.”

People who see marked swans should report color and codes, if visible, along with location and date to the local Wyoming Game and Fish office. They can also leave a message with a name and contact information at 1-800-423-4113.