Tuber swans

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The TB Swan (Cygnus olor) is a species of bird in the Anatidae family. The first name of the animal comes from the bump it has on the beak, called tuber, and the second because it emits rare rather low-power screams.

It is one of the heaviest birds able to fly, males weighing approximately and females about. Adults measure long with a wingspan of . However, it is slightly smaller than the trumpet swan (North America) and roughly equivalent to the singing swan (Eurasie). Juveniles can move in groups but couples are monogamous. The tuberculous swan is a fairly unwieldy bird. It can become very familiar to humans, but can also be aggressive during nesting, including in wild habitats.

The world population is estimated between . It is the most common swan in Europe during nesting periods in summer, especially in northern France. Some of these birds are considered domestic or semi-domestic, although wild populations are now larger. It is present in Great Britain, North and Central Europe, as well as in the North and Central Asia, as far as China. In Western Europe, it can be sedentary or migratory, while in Northern, Eastern and Asian Europe, where water bodies freeze for a long time in winter, it is mainly migratory. It has been introduced into North America, South Africa, Australia and New Zealand, where it is often considered an invasive species.

This species, which is res nullius in France, is the king's animal in the United Kingdom and the symbol of the monarchy in Denmark. It is one of the wildlife species susceptible to the H5N1 strain of the avian influenza virus.

Description

Appearance of adults and measurements
Adults are long (only half for the body) for a span of . On earth, they can reach from high. Males are larger than females (so their neck length measured from the angle of the brood is opposite).

The TB Swan is one of the largest birds able to fly. In Europe, he competes for this title with the fried pelican and the great otard. Males weigh on average, but can go as far as , females about and young at flight between .

The plumage of adults is white. The eyes are hazel. Adult lores are denuded, cuneiform and black in colour. The beak is orange with a black tab at the end. A black bump is present at the base: tuber. It is generally larger in the male during the breeding period.

Juvenile aspect
There are two morphs in swans: the grey morph and the white morph. The grey morph is more common while white swans have a leucistic gene. The white form d