Mute Swan Facts

A male mute swan (cob) can reach 30 pounds and a female (pen) about 20; adults measure 4.6 to 5.2 feet with a wingspan over 8 feet. The S-shaped neck contains up to 25 vertebrae and extends the bird's reach among submerged plants. Its orange bill has a black basal knob, which enlarges in breeding males, and lamellae along the edges that grip pondweed. Webbed feet propel the bird through water, while preen oil helps keep the white feathers waterproof and insulating. Once airborne, mute swans can approach 50 mph, though their weight requires a long takeoff run across water. They belong to the waterfowl family Anatidae, genus Cygnus.

Mute swans are adaptable waterbirds native to temperate Europe and parts of Asia — the UK, France, Germany, Poland, Russia, China — and widely introduced to North America, where they've established sizeable populations. They favour shallow fresh water — wetland, lakes, ponds, and slow rivers — but also brackish coastal lagoons and sheltered estuaries, and the key requirement is a reliable supply of submerged vegetation plus a reedy shoreline for their massive nests.

The mute swan is a strict herbivore specialized for aquatic feeding, living mostly on submerged plants — pondweed, waterweed, stoneworts, and algae — and venturing onto land to graze grasses, grains, and crops when water plants are scarce in winter. Rather than diving, it feeds by "up-ending": tipping forward with head, neck, and front half underwater and tail pointing up, using that long neck to reach 3 to 4 feet down for roots and deep-water plants other waterfowl can't, snipping them with the serrated bill before righting to swallow.

Mute swans are generally monogamous and some pairs remain together for life. A pair holds a breeding territory and may drive away swans, geese, dogs, or people that approach the nest. Despite the name they are not silent, communicating with grunts, snorts, and whistles rather than trumpeting. In a threat display called busking, a cob arches the neck, raises the wing feathers, hisses, and may charge across the water; physical contact can cause bruising injuries.

Breeding begins in early spring, the pair building a massive nest up to six feet across from reeds, sticks, and vegetation at the water's edge. The pen lays 5 to 8 large eggs and incubates them 35 to 42 days while the cob guards the perimeter. The cygnets are precocial — hatching in dense grey-brown down, able to swim and feed almost at once — and often climb onto a parent's back to tuck under the wing for warmth and safety from snapping turtles and large fish. They grow fast but don't get their pure white plumage until the second year, staying with the parents through the first winter before being driven off in spring. Wild mute swans live 10 to 20 years.

The mute swan is Least Concern with a large, generally increasing population, helped by legal protection and its ease in human landscapes like parks and reservoirs. Local threats remain: lead poisoning from discarded fishing weights and shot was historically a major killer (prompting bans), collisions with power lines take flying birds, and cygnets fall to foxes, raccoons, and dogs. In parts of North America, where it is introduced, it is treated as an invasive pest for aggressively displacing native waterfowl and overgrazing aquatic plants.

• IUCN Red List of Threatened Species: Mute Swan
• Cornell Lab of Ornithology: Mute Swan
• National Audubon Society: Mute Swan
• RSPB: Mute Swan Overview