Introduction
The swan is one of the most iconic water birds, with many facts and myths surrounding it. It is famed for its graceful movements, long curved neck and striking white plumage. Although there are four types of swan found within the UK shores, the mute swan is by far the most common and is also the largest of all the species found.
Table of Contents
Mute swan
History
Population growth and threats
Breeding
Feeding
Other swan species found within the UK
Whooper swan
Black swan
Bewick’s swan
Mute swan (Cygnus olor)
The swan is often renouned for being one of the most romantic birds, due to its ability to form an almost perfect love heart, with the neck of its partner.
It is an impressive sight, with an outstretched wingspan of between 208-238 centimetres, height of 140-160 centimetres and weighing in at 10-12 kilograms (RSPB, 2023), it is one of the UK’s largest waterbirds. The adults are recognisable by their all white plumage and vibrant bill, which is orange-red in colour, with a black base. The mute swan is estimated to have a lifespan of around 10 years (The Wildlife Trusts, 2023), with the oldest recorded swan being 15 years (RSPB, 2023).
History
During the Middle Ages, swans were considered to be a valuable commodity and were often traded. The owners of the swans, would place unique markings on the swan’s bill, to identify them. Each year, the cygnets (young swans) would be rounded up and marked, in a ceremony known as swan-upping. Although popular myth suggests that all swans belong to the King, this is not the case, with two companies still owning swans today i.e. Vinters and Dyers. None the less, any unmarked swans on the River Thames, are the property of the monarchy, which accounts for around half of the Thames population (BBC Wildlife Magazine, 2022). The monarchy also still has prerogative over all swans in England and Wales (RSPB, 2023).
Population growth and threats
The mute swan population has shown an increase in numbers in recent times, thought to be mainly attributable to the ban on lead fishing weights, which the birds would historically ingest during feeding, resulting in lead poisoning (RSPB, 2023). Latest figures on population growth, have shown a 16% increase between 1995/96 and 2020/21, with an estimated 53,000 birds, wintering in the UK (British Trust for Ornithology, 2023). Although the mute swan is still protected under the Wildlife and Countryside Act 1981, growing populations have resulted in the mute swan being classified as green or ‘of least concern’ in terms of their conservation status. However, although the threat of lead poisoning, has been largely removed, other threats still remain, including fishing tackle, wind turbines and overhead power lines.
Due to the size and natural habitat of the swan, natural predators are limited. However, foxes do pose a threat, especially during breeding season, when the adult swans will come onto the land to lay and incubate their eggs. Unfortunately, humans also pose a significant threat to the swan population, especially during periods when the swan is land based. Although a hissing adult male swan with its wings outstretched, can be a nerveracking sight, swans have very few defenses against humans. The swan’s behaviour, is designed purely to move you away, rather than cause harm. This is especially true during breeding season, when the adults are guarding the eggs or the cygnets. In order to aid swan welfare, it is essential that humans do not approach swans but rather observe them from a safe distance.
Breeding
At the beginning of the breeding season, the male (cob) constructs a large nest using locally sourced vegetation, near the water’s edge. The female (pen) then lays between five and seven eggs, during April-May (RSPB, 2023). Once the eggs are laid, the female takes responsibility for incubating them, as she has an area beneath her body, known as a breeding patch, which the male swan lacks (Scottish Wildlife Trust, 2020). The male swan does, however, guard the nest and sit on the eggs for short periods, whilst the female finds food.
The eggs take between 35-41 days to hatch (RSPB, 2023). Once they hatch, both parents will play a part, in sitting on the nest and guarding the young cygnets against predators. The cygnets look very different in appearance to the adult swans, with their brown fluffy feathers, short necks, and black-brown bills, they are somewhat reminiscent of the ‘ugly duckling’. In addition to the more commonly found brown plumage, some cygnets may display a white form, known as the ‘Polish swan’. Cygnets from this variation are similar in colour to the adult swan.
Although the cygnets feed independently, from soon after hatching, they remain with the parents for 4-5 months, sometimes riding on the adult swan’s back (RSPB,2023). Even after the cygnets develop their adult plumage, they often remain with their parents, moving into wintering areas during the cooler winter months. Mute swans remain within the UK all year round, flocking together into larger groups during winter, when other birds join the flock from Europe (RSPB, 2023).
The number of breeding pairs has increased significantly within recent years, with an estimated 277% growth rate, between 1967 and 2020. Recent studies suggest that there are now in excess of 7,000 breeding pairs within the UK (British Trust for Ornithology, 2023).
Feeding
Mute swans extend their long necks to reach the bottom of the riverbed, where they generally forage for food. Their primary diet consists of aquatic vegetation, as well as insects, molluscs, frogs, and fish.
As a general rule, swans have sufficient food throughout the year, without the need for supplemental feeding. However, as much of their food is water based, food may be in short supply during periods when water sources freeze over. During these periods supplemental feeding may be helpful. Nonetheless, it is essential to consider the dietary requirements and digestive process of the swan when doing this.
During the feeding process, the swan lowers its head to the bottom of the riverbed, using its flexible neck. In doing this, the swan will not only ingest its food source but also gravel from the riverbed, which aids the digestive process. It is therefore essential that feeding takes place in water, wherever possible.
Although it has become commonplace to feed bread to waterbirds, including swans, bread not only has a very low nutritional content but may also cause digestive problems. It is therefore not a suitable food source. Consideration should be given to the fact that swans have a varied diet, with more suitable and nutritionally rich food alternatives available, including sweetcorn, potatoes, seeds and grains such as wheat or oats.
Other swan species found within the UK
Although the mute swan is the most commonly found species within the UK, three other species can be found, namely the whooper, Australian black swan and the Bewick’s swan. During the winter months, the whooper and Bewick’s swan, join the mute swans within the UK.
Whooper swan (Cygnus cygnus)
The whooper swan arrives from Iceland and Scandinavia during the harsh winter period, returning to their place of origin during breeding season, in the spring and summer months. Although the whooper swan is similar in size to the mute swan, it is lighter in weight, at between 9-11 kilograms (RSPB, 2023) and can be easily distinguished from the mute swan, by its yellow and black bill. Although still relatively low in numbers and rated as amber in terms of its UK conservation status (RSPB, 2023), there are an estimated 19,500 birds within the UK. The whooper swan has more recently started breeding within the far North of Scotland and the Northern Isles, (BBC Wildlife Magazine, 2022), with an estimated 24 breeding pairs within the UK (RSPB, 2023).
Black swan (Cygnus atratus)
As the name suggests, the black swan has predominantly black plumage, with a red bill. The black swan was introduced into the UK from Europe, in the 18th century. Originating from Australia, the swan was brought into the UK to join private collections. However, with some birds escaping and now breeding in the wild, there are an estimated 100-120 pairs breeding within the UK (BBC Wildlife Magazine, 2022). The black swan is slightly smaller than the mute swan, at around 140 centimetres in height and weighing in at around 9 kilograms (BBC Wildlife Magazine, 2022).
Bewick’s swan (Cygnus columbianus bewicki)
The Bewick’s swan, is named after Thomas Bewick, a 18th-century engraver (BBC Wildlife Magazine, 2022). Although similar in colour to the whooper swan, with its yellow and black bill, it is significantly smaller, with an average weight of 6 kilograms (RSPB, 2023). Bewick’s swans winter in the UK, migrating from the cooler breeding grounds of Siberia (BBC Wildlife Magazine, 2022). The Bewick’s swan has declined in number in recent years and is now classified as red in terms of its UK conservation status, with an estimated 4,350 birds wintering in the UK (RSPB, 2023).
References
BBC Wildlife Magazine. (2022) Swans of the UK guide. URL: https://www.discoverwildlife.com/animal-facts/birds/facts-about-swans-of-the-uk/. Date visited: August 30th 2023.
BTO – British Trust for Ornithology. (2023) Mute swan. URL: https://www.bto.org/understanding-birds/birdfacts/mute-swan. Date visited: August 30th 2023.
RSPB. Bewick’s swan. URL: https://www.rspb.org.uk/birds-and-wildlife/wildlife-guides/bird-a-z/bewicks-swan/. Date visited: August 30th 2023.
RSPB. Mute swan. URL: https://www.rspb.org.uk/birds-and-wildlife/wildlife-guides/bird-a-z/mute-swan/. Date visited: August 30th 2023.
RSPB. (2023) Whooper swan. URL: https://www.rspb.org.uk/birds-and-wildlife/wildlife-guides/bird-a-z/whooper-swan/. Date visited: August 30th 2023.
The Scottish Wildlife Trust. (2023) Everything you need to know about mute swans. URL: https://scottishwildlifetrust.org.uk/2020/04/mute-swans/. Date visited: August 30th 2023.
The Wildlife Trusts. (2023) Mute swan. URL: https://www.wildlifetrusts.org/wildlife-explorer/birds/waterfowl/mute-swan. Date visited: August 30th 2023.
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