Despite the name, a mute swan produces a variety of vocalizations. This BirdEden article presents some fascinating facts about these graceful royal birds. Here’s why they are called ‘mute swans’, and why biologists believe that it is necessary to kill these birds.
Did You Know?
Mute swan, one of the heaviest flying birds, is a highly intelligent bird. If you have treated a swan kindly, it will remember you as a friend forever. It remembers its enemies as well. It becomes aggressive when defending eggs or young cygnets.
Mute swan is the second-largest waterfowl species after the trumpeter swan. It is known for its beauty and grace. For centuries, these swans were domesticated for food. The nicks (marks registered with the Crown) on their feet or beaks provided information about ownership. Swans not so marked were considered as Crown property. Therefore, these swans were known as the ‘Royal Bird’.
➺ Mute swan belongs to the waterfowl family Anatidae. The scientific name of the species is Cygnus olor.
➺ The orange bill with a black border and black knob, pure white plumage, long slender neck, and large wingspan make it one of the most beautiful birds in the world.
➺ They are gray and downy when born. Baby swans are called ‘cygnets.’ They are grayish-brown with a gray bill. Within a year, they turn white. Juveniles do not have the knob like adults.
➺ Males weigh about 11 kg (24 lb) and females weigh about 9 kg (20 lb).
➺ A mute swan can be 125 to 170 cm (49 to 67 in) long.
➺ The species can be identified with the pronounced black knob atop the bill. A male (known as a ‘cob’) is larger than a female (known as a ‘pen’), and has a relatively larger knob on its bill.
➺ The cobs may weigh 9.2-14.3 kg (20-32 lb), while the pens may weigh 7.6-10.6 kg (17-23 lb).
➺ The white feathers present on the heads and necks of adult mute swans are often stained orange-brown by iron and tannins in the water.
➺ Their wingspan can be 2.5 meters (8 ft) wide!
Mute Swan Wingspan
Why are they Called ‘Mute’ Swans?
The mute swan is less vocal than its noisy cousins whooper and Bewick’s swans. Generally, they don’t make too much noise. While flying, it never emits sound. Other swans do communicate in the air. So it must have got the name ‘mute swan’.
Mute swans make a variety of sounds, especially when communicating with their cygnets. They grunt, whistle hoarsely, or make snorting noises. Adult swans are known for their rumbling ‘heeorr’, while the cygnets are known for their high-pitched whistles. Aggressive adults produce a hissing noise when defending cygnets.
Where do They Live?
➺ It is native to much of Europe and Asia, and the far north of Africa. It is found throughout Britain.
➺ It was introduced to North America, Australasia, and southern Africa.
➺ It is found in large freshwater areas, such as rivers, lakes, ponds, reservoirs, flood waters, and canals. You may find it in estuaries, especially in winter.
➺ These swans are seen even in urban areas and parks. They can be seen on sheltered coasts.
What do They Eat?
➺ They mainly feed on submerged aquatic plants such as pondweed, coontail, waterweed, wild rice, wild celery, algae, grasses, young cereal crops, etc. Occasionally, they eat insects, fish, and crustaceans.
➺ They get their food by upending. As they immerse their heads into the water, only the tails remain above the surface.
➺ They also feed on artificial food, such as bread offered by the public.
Do Mute Swans Migrate?
➺ During winter, some swans from the north move southwards. Some birds stay in their territories all year.
➺ Many swans prefer staying in the area where they breed. They may move to the coasts.
➺ Swans from the Black and Caspian Seas join the migrating birds from Europe, and they spend the winter in Asia.
➺ Some young swans stay on the wintering zones for one year. Next year, they migrate along with the adults.
How Long do They Live?
➺ Most swans do not live more than 7 years in the wild.
➺ 50% of the young may survive for up to 7 years.
➺ Some mute swans are long-lived (20 to 30 years).
➺ These birds can breed every year after 3 years of age.
➺ A mute swan remains with the same mate for life. Each pair defends a territory of 4 to 10 acres in size.
➺ The black knob of the male swan swells during the breeding season and becomes noticeably larger than his partner’s.
➺ In late March or early April, they build a large cone-shaped nest at the edge of the water.
➺ The female lays five to seven whitish or pale blue eggs after mid April, and incubates them for 35 to 42 days.
➺ The parents do not feed the cygnets but they take care of the cygnets, often until the next breeding season. The pen can be seen carrying the young ones on her back. From about four and a half months onwards, (around September), as the feathers grow, cygnets start taking flying lessons.
➺ A mute swan’s life cycle consists of another important phase, molting period, during which it cannot fly. The molt takes about 6 weeks. Non-breeding birds molt around July. Parents who have to look after the cygnets molt at different times, first the mother and then the father. They molt from August to September. Thus, one of them can always protect the cygnets.
Is Mute Swan an Invasive Species?
Non-native species that become established, spread widely, and cause harm to an ecosystem are called invasive species. As mute swans do not have natural predators, they are overpopulating and damaging ecosystems in Europe as well as in North America.
➺ In 2000, there were 5700 mute swans in Michigan. In 2010, the number increased to 15,500.
➺ This non-native species has established and spread rapidly in North America. There, they are inhibiting the growth of the native wildlife by feeding heavily on water plants. They are responsible for reduced availability of these plants to native wildlife. Thus, they are responsible for displacement of the native species and degradation of wetland habitat.
➺ They even pose a threat to humans. These large birds are not afraid of human beings. This is one of the world’s most aggressive species of waterfowl. They attack people who enter their territory. While defending the cygnets, they may attack small water boats or canoes.
➺ The mute swan’s foraging behavior (they consume immature seeds, remove submerged aquatic vegetation before plant maturation, and uproot whole plants) leads to additional and irrecoverable losses.
➺ According to several biologists, killing adult birds is the quickest and the most humane way of controlling the fast-growing population of mute swans. Because of its high reproductive capacity and long life span, traditional control methods like addling eggs (preventing hatching of eggs) are not effective.
➺ It is impossible to capture, pinion, sterilize, and find homes for thousands of mute swans. They cannot be sent elsewhere either.
➺ Birth control through surgical procedures is very expensive and impractical. So, biologists believe that it is necessary to kill these birds. Killing can help reduce existing populations and prevent further range expansion too.
➺ An exceptionally big Polish cob weighed almost 23 kg (51 lb). This is considered the largest weight ever recorded for a flying bird.
➺ There are six other species of swan in the world, but the mute is the only species that stays in Britain all the year round.
➺ The swishing noise created by the wings of a mute swan in flight can be heard up to half a mile away.
➺ The mute swan is Britain’s largest bird.
➺ A mute swan’s neck has 23 vertebrae, more than any other bird.
Being large and strong birds, mute swans have very few natural predators. Foxes and dogs sometimes attack cygnets. However, pollution and power lines are the major threats. The inexperienced young fliers often fly into overhead power cables and injure themselves. Some are injured due to fishing nets.