A rare visit of several swans to Crawford Pond in Ainsworth was seen Wednesday morning. County naturalist Pam Holz said the swans are trumpeter swans, which are the largest water fowl in North America. She said the swans usually migrate along the Mississippi and don’t make it inland this far. Because of yellow neck collars on several of the swans, Holz believes they were released in Wisconsin. Trumpeter swans had been extinct in Iowa since 1880, but during the 1990s, a breeding program was established to repopulate the species.