The Trumpeter swan is the biggest and the heaviest species of North American water birds. Like all swans, males and females have the same white plumage. Immature swans are ash-gray, some gray feathers remaining on the swans' heads and necks up to one and two years of age. A Trumpeter swan has an angular wedge-shaped head, and the black of its beak appears to merge with its eye. The bill is black, having a border of red on the lower jaw.
The Trumpeter swan is a native of North America. It breeds in central and southern Alaska, parts of Canada and the northern United States. It is present all year through much of its range, though some populations migrate south in winter to ice-free waters, and can be found in the south as far as Arkansas and Texas. These swans live on land, always close to water, in areas with many streams or rivers, and wetlands with open water. The water can be salt, fresh, or brackish. They lay their eggs on or near water.
Trumpeter swans occur in small flocks, often alongside their own family members. Their daily routine varies according to the season. In winter they eat less and rest more, and in spring they eat large quantities of food, and during the day they are very active. The size of the flock also varies seasonally. During spring, the flock size may be almost half that of the size in the fall, as the young birds have left and the mating season is about to start. Trumpeter swans are very territorial during the breeding season. They can be extremely violent towards competitors, other swans, and any animal that is a threat to invading their space. These swans make a variety of sounds, and are best known for their bugle call. Besides this call, they also use movements like head bobbing to warn others of disturbances or when preparing for flight.
Trumpeter swans are monogamous and mate for life. During the mating season, trumpeters reunite with their previous mates or begin the process of courtship to find a mate. Displays of courtship consist of pairs spreading or raising their wings simultaneously, quivering their wings, head bobbing and trumpeting. The mating season is usually March to May. The process of building a nest takes 2 to 5 weeks, with both parents involved in its construction. A female lays 4 to 6 eggs and incubation lasts 32 to 37 days, mainly done by the female. The cygnets are precocial and spend the first 24 hours in their nest; then they begin to swim. Fledging occurs at 91 to 119 days and the cygnets are independent at one year old. They are looked after by both parents during their first year. Trumpeter swans start to mate between 4 and 7 years of age.
Some of the primary threats to Trumpeter swans are habitat loss from expanding human populations, as well as an increase in disturbance by humans. Habitat loss is a problem, particularly in the winter range of these birds. Many swans die from collisions with power lines across wetlands, as they fly low during migration. Another threat is lead poisoning, as the trumpeters ingest fishing sinkers and spent lead pellets during their foraging in wetlands and lakes. Hunting of Trumpeters is now illegal in North America, but illegal shooting does occur. Furthermore, this swan is similar to the tundra swan, this species being legal to hunt, and so trumpeters may be accidentally wounded or killed by hunters.
According to Wikipedia sources, the Trumpeter swan population number is approximately 46,225 birds. This species' numbers are increasing today and it is classified as least concern (LC) on the IUCN Red List.
The main role of Trumpeter swans in the ecosystem is their consumption of aquatic plants, which they dig around to find, and so in many cases this allows water to fill up the holes they make, providing a very valuable nutrient source to plants.