Mute swan

The mute swan (Cygnus olor) is a spectacular water bird that is seen on rivers, lakes, canals and estuaries in many parts of the world. It is native to Europe and Asia and has been introduced to North America and elsewhere. In the United Kingdom, mute swans are found in the wild virtually everywhere except the upland areas of Scotland, Wales and south-west England. Swans are regularly found in urban parks alongside ducks and geese.

In former times swans were bred for their meat, and laws (with severe penalties attached) were passed for their protection. As a “royal” bird, any swans that escaped from captivity were deemed to belong to the Crown. Swans on the River Thames were marked (on the beak) to show their ownership, and the annual custom of “swan upping” by the Royal Household continues to this day, although this is done mainly to monitor the welfare of the birds and to provide a census of swan numbers.

Appearance

The mute swan is one of the heaviest flying birds. It measures between 145 and 160 centimetres (57-63 inches) in length, with the male swan (cob) being larger than the female (pen). The wingspan is up to 240 centimetres (94 inches).

The plumage, in both males and females, is uniformly white. The rounded head is carried on a long, S-shaped neck; the bill is orange with a black base and knob, which is more prominent in cobs than pens. The legs are black.

 

Behaviour

The mute swan flies with slow, powerful wingbeats, neck extended forwards, taking off from either land or water after a short run-up. On land it waddles unsteadily. On the water it swims gracefully with the bill slanted downwards. The head and neck are immersed underwater when feeding, and sometimes the swan upends to take food from deeper water.

Swans are powerful and sometimes aggressive birds, especially if their young are threatened, and can cause severe injury to any dog or person who gets too close.

The “mute” name is not well deserved, because the mute swan produces a variety of sounds including a warning hiss and a range of screams and barks.

 

Breeding behaviour

Mute swans generally mate with one partner for life, although a new mate will soon be sought if a partner dies. However, cases have been noted of a pen “divorcing” a cob by shunning him in favour of another. Such cases are believed to be rare.

Nests are built in reedbeds, being large untidy structures consisting of reeds or rushes. Nestbuilding is mostly done by the pen with the material being fetched by the cob.

The clutch of four to seven eggs (sometimes more) is laid at any time from late March to June and is incubated mostly by the pen while the cob stands guard. The young hatch after about 35 days and are looked after by both parents. Cygnets can swim from a very early age but do not fledge until they are about four or five months old. Full maturity is not reached until they are around four years of age, with full adult size being reached before all the cygnet’s brown feathers are replaced by white ones.

Only one brood is raised in a season.

 

Feeding

Mute swans are mainly vegetarian, feeding on water plants and also grazing on land, but they will also eat insects, crustaceans, newts, tadpoles and small fish.

 

A Good Place to Observe Mute Swans

Abbotsbury Swannery (West Dorset) dates from the colony formed at St Peter’s Abbey in the 11^th century to breed swans for the table. Swans have bred here ever since, and more than 600 birds can be seen here at times. It is therefore possible to view many swans at close quarters but under the supervision of trained staff. 

© John Welford