Trumpeter Swan

The bulk of the trumpeter swan diet consists of a wide variety of aquatic vegetation, including pondweeds and submerged tubers. They will occasionally feed on freshwater invertebrates, snails, worms, and small fish. Adult swans primarily feed in shallow water using their long necks to reach food, but they can also tip forward with their tail feathers in the air to feed up to four feet deeper.

At the Zoo, trumpeters feed on a mix of pre-made waterfowl pellet and greens.

Although not exactly known because trumpeter swans were often extirpated (eliminated) from areas before trained scientists began documenting the species, we know the former breeding range was extensive. Trumpeter swans are migratory and their former wintering grounds could be found from the northwest and northeast coasts of North America, south to the Gulf Coast.

Currently, there are three main populations: along the Pacific coast from Alaska through the northern United States, throughout the Rocky Mountains from Canada to the northern United States, and further inland from central to eastern North America.

Some populations of trumpeter swans are migratory, although many of them are year-round residents. They have specific requirements when it comes to their habitat. They prefer large marshes and lakes that range in size from 40 to 150 acres, as well as shallow wetlands that are one to three feet deep and have a diverse mix of vegetation and open water.

Adult trumpeter swans have few natural predators, but many animals will seize eggs and chicks, including eagles, owls, coyotes, mink, raccoons, and ravens. Adults can be prey for fast predators such as coyotes, bobcats, red foxes, and golden eagles.

Threats from human activity include degradation of both wintering and breeding habitat, lead poisoning from shot or fishing sinkers, illegal hunting, and disturbance near breeding grounds.

Adult trumpeter swans have snow-white plumage with black bills and feet. The neck and head feathers of an adult may be stained a rusty color from feeding in water that contains iron. The dark bill and surrounding feathers of a trumpeter swan blend upward towards dark eyes in a “V” shape. The bill may also have a red border on the lower jaw that gives the bird the appearance of wearing lipstick, while the tongue and inside of the mouth are reddish pink. A young swan, or cygnet, is a sooty gray color with pinkish-colored bills and feet. Their webbed feet and powerful legs allow them to paddle efficiently through water. Long necks make it easy for trumpeter swans to forage on the abundant vegetation available below the surface of shallow lakes and ponds.

Trumpeter swans are dedicated partners who mate for life and remain together year-round. If one member of the pair dies, the survivor will find another mate. Nesting, laying, hatching, and fledging dates vary widely due to weather patterns, sometimes even between years in the same individual sites or regions. Generally, pairs arrive at the breeding grounds in early spring, even before the ice melts. Mates will strengthen their bonds or secure a new mate by performing elaborate courtship displays consisting of simultaneously spreading or raising wings, wing quivering, head bobbing, and trumpeting.

Both parents are involved in nest building and construction can take two to five weeks to complete. Nests are often built on top of muskrat or beaver lodges, floating plant mats, small islands, or on a foundation just above the surface built entirely by the pair out of vegetation. Pairs will often use the same nesting location annually. Each nest is a large mound with a depression in the center, lined with feathers and down. A typical nest can measure up to five feet across and weigh hundreds of pounds! A clutch of one to ten, but more typically four to 6, eggs are laid in the nest. Incubation begins after the last egg is laid. Within four to five weeks, cygnets, or young swans, will hatch.

Cygnets spend their first day or two in the nest, then begin to swim and venture out. They will return to the nest to rest with their parents. The adults will lead cygnets to feeding areas and the young swans can feed themselves. Female trumpeter swans begin to molt at about the time that their chicks hatch out. Females remain flightless for approximately one month, during which time they tend to their chicks. Just as they get their new flight feathers, males begin to molt. Staggered molt cycles ensure that at least one parent remains “grounded” with the chicks until they fledge, which occurs about two months after hatching. After some practice and gaining wing strength, the cygnets fledge (fly) after about three months. In migratory populations, they will remain with their parents through the summer and will migrate with them to the wintering grounds in late fall.

Juvenile swans will migrate with their parents back to summer grounds in the spring, but not cared for by the adults. They remain in sibling groups until they are about two years old and then they begin to seek mates.

True to their name, these swans have a loud and deep honking call that sounds like a trumpet or a bugle. Sometimes they trumpet once, and sometimes twice. They do not have songs, but rather calls including peeps, hisses, gurgles, and murmurs. Different calls have social functions and can communicate defense, alarm, excitement, and reinforce bonds. Vocalizations are combined with other behaviors, such as head bobbing, foot stamping, or splashing. Loud foot-slapping is an aggressive or territorial display while approaching intruders. When trumpeter swans greet each other, they will display loudly in a fury of honking and the flapping of wings spread wide.

Like other waterfowl, trumpeter swans spend a great deal of time pruning and bathing. The long neck allows swans to groom their entire body with their bill after dipping their head, wings, or whole body in water. Preening often follows bathing and full sessions can last for a quarter of an hour. Trumpeter swans are social and congregate in large flocks, especially during migration and non-breeding season. These flocks consist of loose gatherings of pairs, families, and individuals.

Migration is important for many of the trumpeter swan populations, as it allows them to take advantage of resources at different locations throughout the year.