The mute swan is a large, elegant waterbird which often holds its neck in an ‘S’ shape. It has a flat head and generally tilts its bill downwards. Despite its name, the mute swan makes a hissing noise when threatened, and when it flies its wings produce a whistling sound which can be heard up to a mile away. Populations declined up to the 1980s due to lead poisoning from swallowing lead shot and discarded fishing weights. However, as these were replaced with less toxic alternatives numbers have increased.
Breeding birds: 5,800-7,000 pairs
Wintering birds: 79,000
Family: Ducks, geese & swans
Adult male mute swans have white plumage overall. They sometimes have an orange-brown wash on their crown, cheeks, and neck from iron and tannins in water.
On the head, the bill is orange with a black nail, and a prominent black knob on the upper base. The eyes are dark brown with black lores, and the short legs and webbed feet are black.
Female mute swans are similar but are slightly smaller and have a smaller knob on the bill.
Juveniles, or cygnets, have grey-brown plumage that turns white in the first winter, although some grey feathers may remain until the second winter. The eyes are brown, the bill is grey, and the legs and feet are black.
Mute swans breed between late April and early May and produce 1 brood a season. They form pair-bonds for at least one season but not always for life. The nest is built by both adults with the male bringing the material to the female. It is a large mound made of reeds, grasses, and other vegetation, lined with down and softer plant material, and usually placed near water.
Mute swans lay 4-12 pale grey, green, or blue-green eggs which are incubated by both sexes for 36-38 days. The female does most of the incubation, while the male defends the territory. Chicks are precocial and covered in pale grey down with white underneath. Both parents feed and care for them and they will often ride on the female’s back at 10 years old. They are fully feathered at two months and can fly at about 120 days. They remain with their parents until the following spring and reach sexual maturity at 3 or 4 years.
Mute swans feed on a wide range of vegetation, both submerged aquatic plants and seeds and grain they may find on land.
They will occasionally eat small animals such as fish, frogs, molluscs and worms. They catch them with their bill, and filter out the mud and water through lamellae on the sides of the mandibles.
Mute swans breed across most of the UK except for northern Scotland, mid-Wales and the moors of southwest England. Look out for them near sheltered coasts, and inland on wetlands, grassy fields, shallow lakes, ponds, and slow-flowing rivers.
For centuries, swans were domesticated for food and marked with a nick on their feet or beak to show ownership. Any swans that weren’t marked became the property of the Crown. However, the Crown may grant rights of ownership in certain areas, and mute swans on the Thames are ceremonially the property of two livery companies of the City of London; the Vintners’ Company and the Dyers’ Company.
