Mute Swan
Adults of this large swan typically range from 140-160 cm long, although can range in extreme cases from 125-170 cm, with a 200-240 cm wingspan. Males are larger than females and have a larger knob on their bill. On average, this is the second largest waterfowl species after the trumpeter swan, although male mute swans can easily match or even exceed a male trumpeter in mass. Among standard measurements of the mute swan, the wing chord measures 53–62.3 cm, the tarsus is 10–11.8 cm and the bill is 6.9–9 cm. The mute swan is one of the heaviest flying birds. Young swans are called cygnets, they are not the bright white of mature adults, and their bill is dull greyish-black, not orange, for the first year.
The down may range from pure white to grey to buff, with grey/buff the most common. The white cygnets have a leucistic gene. Cygnets grow quickly, reaching a size close to their adult size in approximately three months after hatching. Cygnets typically retain their grey feathers until they are at least one year old, with the down on their wings having been replaced by flight feathers earlier that year.
All mute swans are white at maturity, though the feathers (particularly on the head and neck) are often stained orange-brown by iron and tannins in the water
Habitat
The mute swan is found naturally mainly in temperate areas of Europe then across the Palearctic as far east as Primorsky Krai, near Sidemi. It is partially migratory throughout northern latitudes in Europe and Asia, as far south as north Africa and the Mediterranean. It is known and recorded to have nested in Iceland and is a vagrant to that area, as well as to Bermuda, which places it in 70 countries, breeding in 49 countries, and vagrant in 16 countries.
While most of the current population in Japan is introduced, mute swans are depicted on scrolls more than 1,000 years old, and wild birds from the mainland Asian population still occur rarely in winter. Natural migrants to Japan usually occur along with whooper and sometimes Bewick's swans. The mute swan is protected in most of its range, but this has not prevented illegal hunting and poaching. It is often kept in captivity outside its natural range, as a decoration for parks and ponds, and escapes have happened.
Diet
They feed on a wide range of vegetation, both submerged aquatic plants which they reach with their long necks, and by grazing on land. The food commonly includes agricultural crop plants such as oilseed rape and wheat, and feeding flocks in the winter may cause significant crop damage, often as much through trampling with their large webbed feet, as through direct consumption.
Breeding
Mute swans lay from 4 to 10 eggs. The female broods for around 36 days, with cygnets normally hatching between the months of May and July. The young swans do not achieve the ability to fly before about 120 to 150 days old. This limits the distribution of the species at the northern edge of its range as the cygnets need to learn to fly before the ponds and lakes freeze over.
Population
According to the IUCN Red List, they are classed as Least Concern(LC). The global population is estimated to number approximately 598,000-615,000 individuals. The European population is estimated at 83,400-116,000 pairs, which equates to 167,000-231,000 mature individuals. The overall population trend is increasing, although some populations have unknown trends. The European population is estimated to be increasing.
Threats
The species suffers heavy losses from lead poisoning due to ingested lead fishing weights, lead shot and lead contaminated sediments from mining and smelting activities. Heavy losses have also been recorded from local incidences of copper poisoning. The ingestion of or entanglement in fishing lines and/or hooks can also cause severe injury or mortality as can collisions with overhead lines. The species may be threatened by future oil spills (which can cause death by oil saturation). The species is also susceptible to avian influenza(e.g. strain H5N1) so may be threatened by future outbreaks of the virus. Significant mortality can occur with prolonged freezing weather in winter which prevents birds from feeding .
Conservation
Conservation Actions Underway
EU Birds Directive Annex II. CMS Appendix II. In the U.K. management to decrease competition has shown to be successful.
Conservation Actions Proposed
Legislation to ban the use of lead weights in fishing and measures to minimise mortality from fishing lines and nets should be introduced. The creation and protection of wetland habitats, particularly from mining waste would also benefit the species. Powerlines should be moved or made more visible.