Birds
Mute Swan
Cygnus olor · also called mute swan, white swan
The mute swan is the swan of paintings, park ponds, and wedding decorations — a huge white bird that glides with its neck in a graceful curve and pairs with one partner for life. It is also one of the heaviest birds that can fly, an aggressive defender of its young, and, on the wrong continent, an ecological headache.
Overview
Mute swans are native to temperate Europe and Central Asia, on lakes, rivers, marshes, and sheltered coasts, and have been introduced to North America, southern Africa, and Australasia. They are herbivores, using the long neck to reach submerged water plants, and also graze grass on land. Pairs hold and defend a territory, and outside the breeding season swans may gather in large flocks.
The heaviest flyers
A male mute swan (a cob) weighs 10–12 kilograms, occasionally 15, with a 2.4-metre wingspan — near the upper limit for a flying bird. Getting airborne takes a long running take-off across the water.
Not mute
The name is only relative to the bugling whooper and trumpeter swans. The mute swan hisses, grunts, and snorts, and in flight its wings make a loud, throbbing hum carrying over a kilometre — a sound unique among swans.
For life
Mute swans form lifelong pair bonds, cooperating year-round to hold territory and raise cygnets; “divorce” runs at about 3%, mostly after breeding failure, and a widowed swan usually re-pairs (the “dies of a broken heart” idea is folklore).
Fierce parents
A cob guarding a nest rears up with wings arched (“busking”) and attacks intruders, striking with the hard wing joint and bill. Blows have broken human arms, and swans routinely drive off dogs.
Status
The mute swan is Least Concern and increasing. In North America, where it is introduced, feral swans uproot wetland vegetation and displace native waterfowl, and are subject to control programmes in several regions.
Mute Swan: common questions
Why is it called the "mute" swan if it isn't silent?
The name is comparative. The mute swan lacks the loud, far-carrying bugling and trumpeting calls of the whooper swan, trumpeter swan, and Bewick's swan, so early naturalists called it "mute" by contrast. It actually has a varied repertoire of quieter sounds — a strong hiss when threatened, soft grunts and snorts between family members, and puppy-like noises from cygnets. Its most distinctive sound is not vocal at all — the slow, throbbing "wou-wou-wou" made by the wings of a flying mute swan, which carries for a kilometre or more and is unique among swans.
Do mute swans really mate for life, and would they die of a broken heart?
They do form strong, usually lifelong pair bonds, staying together year-round and cooperating closely to hold a territory and raise cygnets, and pair "divorce" is rare — around 3% of pairs, almost always after a breeding failure. Bonds typically form when the birds are two to four years old, a year or more before they first breed. The romantic idea that a swan pines to death when its mate dies is folklore, though; a widowed mute swan usually finds a new partner, sometimes within the same season, and continues breeding.
Are mute swans dangerous to people?
They can be, during the breeding season. A male mute swan guarding a nest or cygnets is genuinely formidable — it weighs as much as a medium dog, and it attacks by rearing up, running or flying at the intruder across the water, and striking with the hard leading edge of the wing (the carpal joint) and the bill. Blows have broken human arms, and there is at least one recorded death of a person who drowned after a swan capsized his kayak and blocked him from shore. Attacks on dogs are common. Away from the nest, mute swans that have been fed become bold and may approach and nip, but are not seriously dangerous.
Why are mute swans considered a problem in North America?
They are not native there. Mute swans were brought from Europe in the late 1800s to decorate estates and parks, and escapees established feral breeding populations, especially around the Great Lakes and the mid-Atlantic. Each swan eats several kilograms of submerged aquatic vegetation a day and uproots far more than it eats, which can strip a wetland of the plant beds that native fish, invertebrates, and ducks depend on. Mute swans are also highly territorial and drive native waterfowl — including the native trumpeter swan — off nesting and feeding areas. Several US states and Canadian provinces run control programmes, which are contentious with the public because the birds are beautiful and familiar.