This video from the USA says about itself:
24 January 2012
Around 100,000 Tundra Swans migrate along the Pacific Flyway from their Arctic breeding grounds each year to spend the winter in California. On December 16, 2011 one such Swan was found alone on the road in Meridian, north of Sacramento, and brought to International Bird Rescue‘s San Francisco Bay Wildlife Rescue Center for care.
Born just last year, this much-too-thin Tundra Swan was examined upon intake, issued radiographs, and found to have a calloused fracture on her right ulna.
At the time, International Bird Rescue was also caring for a lone Mute Swan, and moved them into an aviary together. The two got along beautifully. We kept the young Tundra Swan at the Center for two weeks to make sure that her fracture site was stable, and she gained a healthy 600 grams.
The most common and widespread swan in North America, the tundra swan is aptly named for its breeding range. Formerly a distinct species, this swan has been lumped together with its Eurasian counterparts, giving it a truly circumpolar range. It is possible, however, that different subspecies will be split again in the future: here.