Tundra Swan
Pfeifschwan (Cygnus columbianus )
The Pfeifschwan (Cygnus columbianus ) is a species of bird in the genus of the Swan (Cygnus ) and the family Anatidae ( Anatidae ).
Sometimes the breeding in the tundra of Eurasia Tundra Swan Cygnus columbianus as a subspecies bewickii is expected to Pfeifschwan.
Appearance
The Pfeifschwan is 120 to 150 cm body length and 4.5 to 9.5 kg body weight, a comparatively small swan. Just as the other northern hemisphere species of the genus it has completely white plumage and black legs. It differs from the Tundra Swan by the almost entirely black bill, which has only at the base in front of the eye a little yellow stain from the Trumpeter Swan (Cygnus buccinator) by the smaller body size and those same yellow spot.
Dissemination
The Pfeifschwan breeds in the tundra of North America in Alaska and Canada. He wintered farther south in the United States. The western populations from Alaska and Yukon winter on the west coast from southern Alaska to California and inland up to Utah and to the south of New Mexico. The further east breeding populations winter in the Great Lakes region and along the east coast from Maryland to Florida and Texas.
Habitat
The Pfeifschwan breeds in wetlands in Arctic tundra, lakes, ponds and rivers. The train into winter quarters will be held in September and October. Here holds the Pfeifschwan in larger family groups usually near the coast, but is yet to be found mainly in fresh and brackish water.
Nutrition
The Pfeifschwan feeds on aquatic plants, especially of herbs spawning ( Potamogeton ), and grasses, but also of shells and insects, such as water beetles and dragonfly larvae. In winter quarters, and during the passage he also takes crops to be.
Reproduction
During the winter half of the year Pfeifschwäne live socially. During the breeding season, however, they are very territorial.
The pairs form in age from two to three years and will remain for a lifetime together. The breeding period starts from the end of May. The nest is built of grasses and moss on elevated terrain, often on islands or in the vicinity of water. The female lays two to seven white eggs and incubates them then 30-32 days, while the male guards the nest. The chicks are precocial and fledge after about nine to ten weeks, then remain still throughout the winter and during the return flight to their breeding grounds with parents.
Natural enemies, threat
Cygnets and moulting birds are sometimes coyotes (Canis latrans ), wolves (Canis lupus) or golden eagles (Aquila chrysaetos ) captured. The Pfeifschwan is hunted in some states of the USA. But it die again and again birds of lead poisoning by lead shot ammunition they take with the food from the bottom of the waters. Overall, the stocks are stable and have increased again since mid-20th century. After censuses have shown in their winter quarters in the 1950s, an average of 78,000 birds, this number has increased in the period 1970-1974 to an average of 133,000 birds.