Anser cygnoides
- In the Burin Mountains, the swan goose, or Chinese goose, forms pairs only on the seventh day after arrival—April 16th. In other regions, pairs may form during wintering or migration.
- During molting in July and early August, male swan geese remain with their brood, unlike other geese, which leave their young.
- The bill of the swan goose is明显 longer than that of all other geese, distinguishing it from other members of its group.
- The swan goose nests in a wide variety of places—from rocks to marshes and plateaus.
- Male and female voices differ in pitch and duration.
- About 90 % of the world population winters in the middle Yangtze valley.
- The swan goose is a rare wild goose whose domesticated descendants have become common on Asian farms.
- In the early 21st century more than half the population failed to breed because of drought in Dauria.
- Numbers in Russia have fallen to about 500 pairs and continue to decline.
- The characteristic two-toned neck pattern makes the neck look thin and long from a distance.
Старост
Swan geese typically live from 23 years and 3 months to 38 years and 9 months, with a maximum lifespan of 31 years and a theoretical lifespan ranging from 21 years and 9 months to 27 years and 11 months; the species reaches sexual maturity between 2 and 3 years of age. The gosling’s eyes open at birth, and an embryo develops inside an egg. The young are covered in down and protected by their parents for a period lasting from 1 day to 2 months and 1 week. The adult stage begins when the bird is capable of flight and reproduction, and lasts from 2 to 20 years.
Фенотип
Goslings have small beaks for grazing on grass, yellow down that retains heat and conceals them from predators, and weak webbed feet; adult swan geese possess a large black beak with serrations for cutting plants, grey-brown feathers that aid in flight and warmth retention, strong orange webbed feet for walking and swimming, a long neck to reach plants from water and grass, and wide wings for long migrations.
Физиологија
The body length of a swan goose ranges from 85 centimeters to 1.15 meters, with an adult's body length between 85 centimeters and 0.95 meters; the species weighs from 2.8 to 3.7 kilograms, while the average body mass is 3.31 kilograms. The wingspan measures from 1.65 to 1.85 meters. During the "Embryo" stage, the developing gosling has a body mass of 140 to 170 grams and a body length of 8 to 9 centimeters. A gosling also exhibits a body mass from 100 grams to 2 kilograms and a body length from 20 to 50 centimeters.
Станиште
Swan geese inhabit temperate mixed forests with warm summers and many oak, birch, and maple trees, as well as flooded meadows where water frequently covers the ground and there is abundant grass, shallow waters along the shore with crabs, taiga characterized by cold winters and numerous coniferous trees such as spruce and pine, freshwater bodies, freshwater banks and backwaters, lakes and ponds, swamps and marshes, dry land, and terrestrial forests; the species can be found at elevations up to 1.2 kilometers above sea level; they thrive in climates with very hot summers exceeding +25…+30 °C, consistently high humidity due to nearly constant rainfall, frequent rain and cool summers with snow in winter, warm summers with frequent rain, or warm and pleasant summers with abundant rainfall.
Склониште
Swan geese are found on the banks of lakes or rivers amongst tall grass, and construct or utilize nests for laying eggs and raising young. The nest is a structure built from grass, feathers, and down.
Географија
Swan geese are distributed across the Palearctic realm, freshwater ecosystems, the Nearctic realm, and marine environments. The species inhabits the Taklamakan Desert, Celtic broadleaf forests, broadleaf forests of Western Europe, beech forests of the English lowlands, Balkan mixed forests, and Baltic mixed forests.
Храна
The Chinese goose feeds exclusively on plants, pecking grass, aquatic plants, roots, and grains in fields. The method of obtaining food is to peck at plants on land and shallow water. The feed consists of grasses, aquatic plants, grains, rhizomes, algae, grass, roots, grain, and plant matter. The feeding strategy involves searching for and obtaining food, and grazing. The daily food requirement is from 400 g to 0.9 kg. Prey items include beetles, diptera, waterfowl, butterflies, decapods, ribbon worms, mollusks, and polychaetes. Predators (that hunt it) include eagles, wolves, and wolverines (genus).
Размножавање
The embryo develops for 4 weeks; a clutch has 4 to 8 eggs, and pairs of swan geese are permanent. The female constructs a nest on the ground and lays eggs, while the male defends the territory, and both parents lead the goslings. The young reach maturity from 2 to 3 years of age, and the reproductive interval is 1 year; the number of offspring is 4 to 8.