"Swan"
The smooth sand, clouds and water play on the clear waves, and I love chasing the green lotus in the lake.
The corners of its mouth are as red as snow-like feathers, and it sings to the sky with its twittering throat and spreading wings.
Swan refers to the birds of the genus Cygnus (scientific name: Cygnus). There are 7 species in total and they are migratory birds. It is distributed on every continent except Africa and Antarctica. It is the largest group of individuals in the Anatidae family. The neck is slender, exceeding the body length or the same length as the body; the base of the mouth is high and the front end is flat, with the eyes exposed first; the tail is short and round, with 20 to 24 tail feathers; the webs are powerful, but the hind toes do not have webs. They like to live in groups in lakes and swamps and feed mainly on aquatic plants, but also snails and molluscs. Most are monogamous and stay together for life. There are many courtship behaviors, and the male and female will tend to perform the same actions in unison, and they will also preen each other's feathers considerately. They reproduce once a year, and their eggs are relatively large. For example, whooper swan eggs weigh more than 400 grams. Young birds are precocious chicks. When migrating, they will gather in large groups, but they still move in small groups.
Swans are graceful in shape, with long necks, solid bodies, and big feet. They have a solemn expression when gliding in the water. When flying, they extend their long necks forward and flap their wings slowly. When migrating, they form a diagonal or "V" formation at high altitude and move forward. Other waterfowl are not as fast in water or in the air as swans. Swans dive into shallow water with their heads (not dive with their whole bodies) to feed on aquatic plants.
When swimming or standing, mute swans, (and dumb swans) and black swans (C. atratus) often put one foot behind their back. Male and female swans are similar. Different sounds can be made from the trachea. In some species, the trachea is loop-shaped within the sternum (as in cranes). Even mute swans (the least vocal species) known as mute swans often hiss or emit soft snores or high-pitched grunts. Except during the breeding season, swans live in flocks. They mate for life. Courtship behavior includes touching beaks or head-to-head contact. The eggs are incubated by female swans, with an average of 6 eggs per clutch. The eggs are pale and have no markings. The male keeps watch near the nest; in some species, the male also incubates the eggs alternately. After repelling the enemy, the swan roared in victory like a wild goose. The chicks have short necks and dense velvet. The chicks can run and swim a few hours after hatching, but their parents still take care of them for several months. Some species of chicks can lie on their mother's back. The feathers of juvenile birds are gray or brown with mottled stripes until they are over two years old. Sexual maturity is reached in the third or fourth year.
In nature, swans can live about 20 to 50 years. There are 7 to 8 species in the genus Cygnus; some may be subspecies of the same species. Five species live in the northern hemisphere, all of which are white with black feet; the mute swan has an orange beak with a black wart-like protrusion at the base of the beak, a curved neck, and upward raised wings; the trumpeter swan (C.cygnusbuccinator) has a high-pitched song and a long beak. Black; the named subspecies of whooper swan (C. cygnus cygnus) has a rough cry, black beak, and yellow beak base; Bewick's swan (C. columbianus bewickii) is smaller and quieter; Jankovsky's swan ( C.columbianusjankowskii) may be the eastern type of Bew's swan; the named subspecies of cygnet is the whistling swan (C.columbianuscolumbianus). It makes sounds and whistles, has a black bill, and has small yellow spots around its eyes. Some ornithologists (especially those in the United States) often place the latter four species of swans in the genus Olor, while only placing mute swans in the genus Cygnus. Trumpeter swans were once on the verge of extinction (there were less than 100 in the United States in 1935). Later, their numbers have rapidly recovered in national parks in Canada and the western United States, but in the mid-1970s, their numbers were only about 2,000. It is the largest swan, with a body length of about 1.7 meters (5.5_) and a wingspan of 3 meters (10_), but it is lighter than the mute swan. Mute swans can weigh up to 23kg (50 pounds) and are the heaviest flying birds. There are black swans (Australia) and two light red-footed types (South America) in the southern hemisphere: the black-necked swan (C. melancoriphus) is untamed but beautiful, with a white body, black head and neck, and obvious red wattles on its bill; flat bill The swan (Coscorobacoscoroba) is all white and is the smallest swan. It may be related to the whistling duck (whistlingduck).
Swans are the champions of flying, reaching a height of 9 kilometers, and can fly over the world's highest mountain - Mount Everest.