The Whooper Swan (Cygnus cygnus) is a large Northern Hemisphere swan. It is the Eurasian counterpart of the North American Trumpeter Swan.
Whooper Swans require large areas of water to live in, especially when they are still growing, because their body weight cannot be supported by their legs for extended periods of time. The Whooper Swan spends much of its time swimming, straining the water for food, or eating plants that grow on the bottom.
Whooper Swans pair for life, and their cygnets stay with them all winter; they are sometimes joined by offspring from previous years. Their preferred breeding habitat is wetland, but semi-domesticated birds will build a nest anywhere close to water. Both the male and female help build the nest, and the male will stand guard over the nest while the female incubates. The female will usually lay 4-7 eggs (exceptionally 12). The cygnets hatch after about 36 days and have a grey or brown plumage. The cygnets can fly at an age of 120 to 150 days.
Source: en.wikipedia.org/wiki/Whooper_Swan - 06.10.2010
Who comes from the Siberian or East European Taiga, like the Whooper Swan, will not be impressed by a litte bit ice.