H.J. Ruiz – Avian101

Mute Swan – Spec. Name: Cygnus olor

This is a species of swan, and thus a member of the duck, goose and swan family Anatidae. It is native to much of Europe and Asia, and (as a rare winter visitor) the far north of Africa. It is also an introduced species in North America, Australasia and southern Africa. The name ‘mute’ derives from it being less vocal than other swan species. Measuring 125 to 170 centimetres (49 to 67 in) in length, this large swan is wholly white in plumage with an orange bill bordered with black. It is recognisable by its pronounced knob atop the bill.

Mute Swan

Adults of this large swan range from 125 to 170 centimetres (49 to 67 in) long with a 200 to 240 centimetres (79 to 94 in) wingspan. They may stand over 120 centimetres (47 in) tall on land. Males are larger than females and have a larger knob on their bill.

The Mute Swan is one of the heaviest flying birds, with males (known as cobs) averaging about 12 kilograms (26 lb) and the slightly smaller females (known as pens) weighing about 9 kilograms (20 lb). An unusually big Polish cob weighed almost 23 kilograms (51 lb), surpassing the longer-bodied Trumpeter Swan to make it the heaviest waterfowl ever recorded. Its size, orange-reddish bill and white plumage make this swan almost unmistakable at close quarters. Compared with the other Northern white swans, the Mute Swan can easily be distinguished by its curved neck and orange, black-knobbed bill. Unlike most other Northern swan species (who usually inhabit only pristine wetlands without regular human interference), the Mute Swan has, in some parts of the world, become habituated and fearless towards humans. Such swans are often seen at close range in urban areas with bodies of water.

Young birds, called cygnets, are not the bright white of mature adults, and their bill is dull greyish-black, not orange, for the first year. The down may range from pure white to grey to buff, with grey/buff the most common. The white cygnets have a leucistic gene. All Mute Swans are white at maturity, though the feathers (particularly on the head and neck) are often stained orange-brown by iron and tannins in the water.

Mute Swans nest on large mounds that they build with waterside vegetation in shallow water on islands in the middle or at the very edge of a lake. They are monogamous and often reuse the same nest each year, restoring or rebuilding it as needed. Male and female swans share the care of the nest, and once the cygnets are fledged it is not uncommon to see whole families looking for food.

All photographs are © H.J. Ruiz – Avian101

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