The whooper swan (Cygnus Cygnus) is a species which nests in Scandinavia, Northern Russia and even the arctic area.
It is a large scaled bird. Due to the cold wave it comes to Romania at the end of October, but most specimens come in December. This bird has a slim allure, with a bright white plumage and a bicolored bill: yellow with a black base. Youngsters are grey and they have a pink-yellowish bill.

The cry of the whooper swan was symbolically declared the winter song in the Danube's Delta. The cry of an entire flock can be heard from miles away.

The whooper swan is an excellent flyer regardless of its weight. A male can weigh up to 11 Kg.

In the morning, the swan travels considerable distances to reach its feeding areas. It prefers farming areas, limitrophe to the Danube's Delta. While resting, it prefers wide and shallow lakes, where boats cannot reach.

It feeds with wheat, barley and since the past years also with rape. There have been spotted flocks with up to 2000 specimens, which have destroyed entire crop fields. Due to this fact, the farmers in Romania now receive compensations for each hectare of crop destroyed by these birds.

Besides the human, the whooper swan does not have any natural enemies. During harsh winters, weak specimens hunted by foxes and jackals.