The Whooper Swan is so called after the trumpeting "whoop-whoop" sound it makes. A large, white swan native to Eurasia, it is smaller than its North American relative, the Trumpeter Swan but larger than the similar-looking Bewick's swan. Unlike the Bewick's, the Whooper has more yellow on its bill than black, the yellow extending to its nostrils and forming an acute angle.
Both Whooper and Bewick's are strong flyers migrating long distances in sub-Arctic/northern Eurasia.
Like most swans, Whoopers mate for life; they also often remain in family groups for a year to two after offspring have fledged.
They can be noisy birds, especially in spring, when making their famous trumpeting whoop to claim territory and partner.
The choirmaster conducts . . .
the choir sings . . .
. . . and others are moved to join in.
Comparison of swan's heads: click for link to other swans