Big Swan, also known as Cough Swan and Yellow-billed Swan, belongs to Flower Suborder, Flower Suborder and Flower Suborder without subspecies differentiation. Mainly distributed in Asia and Europe. They are widely distributed. If the climate is mild, their breeding area can be extended northward and their breeding time can be advanced. In the years with low temperature, it is distributed in the Yangtze River basin and nearby lakes in China in winter, and moved to North China, Xinjiang, Northeast China, Mongolia, Siberia and other places to breed in spring. I like living in the open shallow water, where there are lush aquatic plants. It is a national second-class protected animal in China.
Height, body length 120- 160cm, wingspan 2 18-243cm and weight 8- 12kg. Both sexes are of the same color, and females are smaller than males. All the feathers are white, only the head is slightly brown. The mouth is black and the base of the upper mouth is yellow. This macula extends forward along both sides to the bottom of the nostril, forming a trumpet shape. The cygnet of the same genus also has similar characteristics, but the macular area of cygnet is limited to both sides of the mouth floor and does not extend below the nostrils along the mouth edge. Young birds are grayish brown, with dark head and neck, and lighter lower body, tail and flight feathers; It took a year to grow completely as white as the feathers of an adult bird.
Sex likes to live in groups, except in the breeding season, especially in winter, and often live in groups with families as units, sometimes as many as dozens to hundreds of large groups. He is timid and extremely vigilant. He moves and lives far from the shore, swims in the open water and even lives in the water far from the shore at night. They mainly feed in the morning and evening, feeding on leaves, stems, roots and seeds of aquatic plants, as well as a few mollusks, aquatic insects and aquatic invertebrates. Their mouths have a strong ability to dig out food, and they can dig out food buried 0.5 meters under the mud.
Usually, they are more active on water. Good at swimming, generally not diving. When swimming, the neck is straight up and perpendicular to the water surface. Swimming is slow and leisurely, with beautiful posture. You seldom take off unless you have to. Because the body is big and heavy, it is not flexible to take off. It needs two wings to beat the water violently and two feet to run a distance on the water to fly. Sometimes when flying and swimming, the sound is monotonous and rough, like a horn. They are one of the highest flying birds in the world. They can fly over Mount Everest, the roof of the world, at an altitude of over 9000 meters.
Migration usually occurs in small groups or family groups with more than 6-20 animals. Migration is mostly carried out along lakes, rivers and other waters, and stops for food along the way. Nest on dry reeds on lakes, ponds and islands. Each nest lays 4-7 eggs, and a nest of eggs is borne by females alone. Young birds are precocious and can follow their parents for food soon after hatching.