The Captains described two types of swans in their journals. The larger of these birds is thought to be the trumpeter swan (Cygnus buccinator) and the smaller is now called the tundra swan (Cygnus columbianus). As they noted in their extended journal entries, the tundra swan was more numerous than the trumpeter swan, a bird that became threatened with extinction at the turn of the 20^th century but whose numbers have now increased. Neither bird had been formally identified at the time of the Corps of Discovery.