Cygnus buccinator
trumpeter swan

Trumpeter swans are found throughout the Nearctic Region, mainly in Alaska, Canada, and the northern United States. A large percentage is found in Alaska, specifically in Prince William Sound and the Copper River Delta. Some trumpeter swans have even taken up residence in Yellowstone Park, Wyoming. (Grant and Henson, 1994; Henson and Cooper, 1993; Mills, 1991; Schmidt, et al., 2009; Squires and Anderson, 1997; Squires, 1995)

Trumpeter swans live on land but always in close proximity to water. They are found in wetlands with open water and areas with many rivers or streams. Waters can be salt water, fresh water, or brackish water. Their climate ranges from temperate to polar. Reasons for their choice of environment have to do with their diet and nesting habits. Cygnus buccinator feeds off many plants native to those areas. They are also known for laying their eggs near or on the water. They seek out the same habitat type for wintering grounds. (Grant and Henson, 1994; Henson and Cooper, 1993; Mills, 1991; Proffitt, 2009; Schmidt, et al., 2009; Squires and Anderson, 1997; Squires, 1995)

As the largest North American swans, these birds can weigh up to 13.5 kg and measure approximately 1.6 m in length. Wingspan can often exceed 2 m. When they are young "cygnets", the bill features some degree of pink but is always black at the base. The feet and tarsi (portion of the foot that makes up the ankle region) may be a grey-yellow. The body is light to dark grey, and will gradually whiten with age. At age two, most but not all of their feathers have turned white, except for a few on the upper portion of the body.

At adulthood their feet, bill, and tarsals are black. They have pink to red mouths which can be seen as a small pink or red line (a 'grin') on the bill. Their feathers are completely white. There is also a small percentage of trumpeter swans that have a grey-white tint for feather color instead of pure white.

They appear very similar to tundra swans (Cygnus columbianus), with the most reliable differences found near the beak. Viewed face-forward or top-down, trumpeter swans have an angular, v-shaped forehead at the base of the beak. Tundra swans have a curved or straight forehead. Most tundra swans have a yellow-white 'teardrop' on their black beak, however this is not always a reliable field mark. (Slater, 2006)

Trumpeter swans are monogamous and mate for life. During mating season, trumpeter swans reunite with their former mates or begin a process of courtship to secure a mate. Courtship displays consist of pairs simultaneously spreading or raising wings, wing quivering, head bobbing and trumpeting. (Slater, 2006)

Adults begin mating at 4 to 7 years of age. Mating usually occurs from March to May. Nest-building can take 2 to 5 weeks to complete, and both parents are involved in construction. The nests range from 1.2 to 3.6 m in diameter and are usually surrounded by water. The materials used in nests building include various aquatic vegetation, grasses, and sedges.

After copulation and fertilization, the females lay 4 to 6 eggs. Incubation lasts for 32 to 37 days, done mainly by the female. The young, precocial cygnets spend their first 24 hours in the nest, then begin to swim. They fledge after 91 to 119 days and are independent after one year. (Slater, 2006)

Both parents contribute to nest building which lasts 2 to 5 weeks. The female will perform the majority of incubation. Unlike many birds, trumpeter swans do not have a specialized brood patch and instead will incubate the eggs using their feet. Upon hatching, the young are precocial but still require significant parental care. Both parents care for the cygnets throughout their first year. (Slater, 2006)

Young trumpeter swans often have survival estimates from 40% to 100%, adult swan survival increases to 80% to 100%. The oldest captive trumpeter swan on record was 33 years old. In the wild, the oldest known individual was 24. (Krementz, et al., 1997; Slater, 2006)

Trumpeter swans live in small flocks, often with members of their own family. Their daily routine varies from season to season. In winter they rest more and eat less, while in spring they consume large amounts of food and are very active during the day. Flock size also varies seasonally. In spring, flock size can be almost half than found in the fall because the young have left and the breeding season is about to begin.

Trumpeters are known to be very territorial during the mating season. They can become incredibly violent to competitors, other swans, or any animals that could pose as a threat that invades their space.

Trumpeters are migratory birds. When the weather gets colder (mid-October to late November) they begin a slow migration southward, with the first stop usually at Yellowstone National Park, and other parts of Wyoming and also North Dakota. They remain there until the water freezes over and then they move onto places such as Utah and Arizona where the winter climate is much warmer. Many trumpeter swans spend the winter on the western coast of Canada, Alaska, and Washington. (Earnst, 1994; Slater, 2006)

Trumpeter swans are very territorial and rarely leave their nests unguarded. Their nests are built on or near aquatic vegetation, and the adults do not need to wander far from the nest for food. Thus, the home range during the breeding season, though not calculated, is not expected to be substantial. (Slater, 2006)

Trumpeter swans produce a variety of sounds, but they are known for their low bugle call. In addition to the bugle call, they also use motions such as head bobbing to alert others of disturbances or in preparation for flight. Trumpeter swans are very social creatures except for in times of mating, when they become quite territorial. Pheromones are also used in mating rituals. The female emits pheromones when she is ready to mate. Breeding pairs perform visual, synchronous displays which likely reinforce the pair-bond. Trumpeter swans call to warn the flock of impending danger. Trumpeter swans perceive their environment through visual, auditory, tactile, and chemical stimuli. (Slater, 2006)

As cygnets, trumpeter swans' diets are mostly comprised of aquatic invertebrates. At five weeks of age, most cygnets have converted to a nearly herbivorous diet. This diet consists mostly of tubers, roots, stems, leaves and occasionally insects. In Alaska during mating season, the wetland plants commonly known as horsetail (genus Equisetum) and Lyngbye's sedge (Carex lyngbyei) are consumed in great quantities. However, because of the wide distribution of the species there are some variations of their diet such as duck potato (Sagittaria latifolia), water weeds (genus Elodea), pondweeds (genus Potamogeton) and sago pondweed (Potamogeton pectinatus) tubers.

Trumpeter swans attain their food by foraging underwater with tails bobbing in the air. They also yank plants out of the damp ground, with most of the plant intact. (Slater, 2006)

Although adults aggressively defend their nests, ground nests are easy targets for land predators. Many predators, such as bears, wolves and coyotes, wolverines, raccoons, and common ravens are known to snatch eggs. Post-hatchlings and adults are prey to fast predators such as coyotes, bobcats, red foxes, and golden eagles. The main predator of adult trumpeter swans is mankind. Humans have hunted more of these swans than anything else.

Trumpeter swans are aggressive towards predators, and at 12 kg with a 2 m wingspan, they can potentially inflict serious damage. Trumpeter swans do exhibit warning behaviors before they attack, including head bobbing and hissing. (Kraft, 1946; Schmidt, et al., 2009; Slater, 2006)

Trumpeter swans' main role in the ecosystem is linked to their diet. Trumpeter swans eat many insects when they are young. As they grow they switch to roots and aquatic plants, digging around to get them which in many cases allows water to fill the remaining holes supplying a very valuable nutrient to the plants. Cygnus buccinator can also be a host to a small number of parasites including tapeworms (Anoplocephala perfoliata), caecal paramphistomids (Zygocotyle lunata), trematode flukes (Echinostoma revolutum), another type of trematode (Orchipedum tracheicola), filarial worms (a nematode found in the heart) of the species Sarconema eurycerca, and other forms of tapeworms (Hymenolepis). (Cowan, 1946; Slater, 2006)

Trumpeter swans used to be a commercial hunting target for feathers and skins, but over-hunting led to their marked decline. Today, only illegal hunting occurs. (Slater, 2006)

Trumpeter swans are very territorial animals, especially during mating season, and humans that enter their territory may be attacked. (Slater, 2006)

Historically, birds were heavily harvested for decorative feathers and skins. Many birds continue to be hunted illegally. If birds are illegally shot and do not die immediately, an embedded bullet may cause lead poisoning and eventual death. Today, habitat destruction is likely the greatest threat to trumpeter swans. Efforts are being made to protect trumpeter swans and their wetland habitat, with many states involved in reintroduction programs. As migratory birds, they are protected under the United States Migratory Bird Act.

Trumpeter swans are also affected by recent population increases of invasive mute swans. Mute swans are markedly more aggressive and will often chase trumpeters away from their shared wetland habitats. Some states are involved in mute swan control programs with the goal of reducing populations to allow for native swans to return. (Slater, 2006)