Bird lovers from all over are flocking to Yukon to catch a glimpse of trumpeter swans passing through on their way to their breeding grounds in Alaska.

The territory has created an annual festival around the spring migration, "A Celebration of Swans," which ran this year from April 13 to 21.

Bird watcher Carl Fabiani drove to Yukon from Wilkeson, Wash., for the event.

"They are a beautiful bird for one thing and people are just attracted to that sort of thing, the migration aspect and the fact that spring is coming and everybody coming back north again."

Trumpeter swans are the largest waterfowl in North America. They weigh about 10 kilograms, live about 20 years and mate for life.

Hunters drove them to the verge of extinction in the last century but their numbers have increased dramatically over the past few decades.

Jim Hawkings, a biologist with the Canadian Wildlife Service said the Pacific coast population numbered about 5,000 back in 1980. Today they number about 26,000.

"They are such a big, graceful and attractive bird and they need these really nice marshes to live in — they just make a perfect ambassador or messenger for wetland conservation."

Wildlife viewing biologist Carrie McClelland said the Celebration of Swans, and programs at the Swan Haven Interpretive Centre at Marsh Lake, aim to educate Yukoners about the importance of early spring open water and marshes for the swans.

"They have flown all the way up from Vancouver and other places and they are really tired and they need to refuel and they need to do that safely and there are only three or four locations where they can do that," she said.