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trumpeter swan

Cygnus buccinator

What do they look like?

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 is mostly pink but is always black at the base. The feet and ankles may be a grayish-yellow. The body is light to dark gray, and will gradually whiten with age. At age two, most of their feathers have turned white, except for a few on the upper portion of the body.

Adult trumpeter swans have black bills, feet and legs. 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 number of trumpeter swans that have a gray-white tint for feather color instead of pure white.

They appear very similar to tundra swans, 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 feature. (Slater, 2006)

  • Sexual Dimorphism
  • sexes alike
  • Range mass
    9.5 to 13.5 kg
    20.93 to 29.74 lb
  • Range length
    1.4 to 1.6 m
    4.59 to 5.25 ft
  • Range wingspan
    2.0 to 2.4 m
    6.56 to 7.87 ft

Where do they live?

Trumpeter swans are found scattered across North America, 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. Some trumpeter swans migrate to Michigan during the spring to breed and raise their young during the summer. (Grant and Henson, 1994; Henson and Cooper, 1993; Mills, 1991; Schmidt, et al., 2009; Squires and Anderson, 1997; Squires, 1995)

What kind of habitat do they need?

Trumpeter swans live on land but always near 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. Trumpeter swans feeds off many plants native to wet habitats. 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)

How do they reproduce?

Trumpeter swans are monogamous, meaning one male and one female pair together to breed. Like many swan species, trumpeter swans keep the same partners throughout their entire lives. During mating season, trumpeter swans reunite with their former mates or begin courtship displays to find a mate. Courtship displays consist of pairs spreading or raising wings, wing quivering, head bobbing and trumpeting together. (Slater, 2006)

Adults begin mating at 4 to 7 years old. Mating usually occurs every year, from March to May. After swans are reunited with their mates, both will begin to build a nest that will take 2 to 5 weeks to complete. Nests are built on the ground or mounds of vegetation surrounded by water. The nests range from 1.2 to 3.6 m in diameter and are built with aquatic plants, grasses, and sedges.

Females lay 4 to 6 eggs, and will keep the eggs warm for 32 to 37 days until the eggs hatch. Baby swans are called "cygnets." The young cygnets spend their first 24 hours in the nest, then begin to swim. They fledge (are able to fly and leave the nest) after 91 to 119 days but will stay near their parents until they are about a year old. (Slater, 2006)

  • How often does reproduction occur?
    Trumpeter swans breed once yearly.
  • Breeding season
    Trumpeter swans breed from March to May.
  • Range eggs per season
    4 to 6
  • Range time to hatching
    32 to 37 days
  • Range fledging age
    91 to 119 days
  • Average time to independence
    1 years
  • Range age at sexual or reproductive maturity (female)
    4 to 7 years
  • Range age at sexual or reproductive maturity (male)
    4 to 7 years

Both parents participate in nest building which lasts 2 to 5 weeks. The female will perform most of the egg incubation until the young hatch. Unlike most birds, trumpeter swans do not cover the eggs with their stomachs, but instead use their feet to keep the eggs warm. The young are born precocial, meaning they have downy feathers and eyes are almost open. Cygnets are ready to leave the nest within a few days of hatching, but will remain with their parents who care for them through their first year. (Slater, 2006)

  • Parental Investment
  • precocial
  • male parental care
  • female parental care
  • pre-fertilization
    • provisioning
    • protecting
      • female
  • pre-hatching/birth
    • provisioning
      • male
      • female
    • protecting
      • male
      • female
  • pre-weaning/fledging
    • provisioning
      • male
      • female
    • protecting
      • male
      • female
  • pre-independence
    • provisioning
      • male
      • female
    • protecting
      • male
      • female
  • post-independence association with parents
  • extended period of juvenile learning

How long do they live?

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)

  • Range lifespan
    Status: wild
    24 (high) years
  • Range lifespan
    Status: captivity
    33 (high) years

How do they behave?

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 towards 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, with the first stop usually at Yellowstone National Park, and other parts of Wyoming and also parts of North Dakota. They remain there until the water freezes over and then they move onto scattered places including 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)

Home Range

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)

How do they communicate with each other?

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 call to warn the flock of impending danger. Trumpeter swans are very social creatures except for in times of mating, when they become quite territorial. Breeding pairs perform visual displays together which likely reinforce the pair-bond. (Slater, 2006)

What do they eat?

Young cygnets eat mostly aquatic insects. At five weeks of age, most cygnets have converted to a nearly herbivorous diet. This diet consists of tubers, roots, stems, and leaves aquatic vegetation as well as occasional insects. In Alaska during mating season, the wetland plants commonly known as horsetail and Lyngbye's sedge 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, water weeds, pondweeds and sago pondweed tubers.

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

  • Animal Foods
  • aquatic or marine worms
  • Plant Foods
  • leaves
  • roots and tubers

What eats them and how do they avoid being eaten?

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. Young cygnets 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)

What roles do they have in the ecosystem?

Trumpeter swans' main role in the ecosystem is linked to their diet. Trumpeter swans eat many insects when they are young, but as they grow they switch to roots and aquatic plants. Swans use their beaks to dig around plant roots and will yank up whole plants from the ground. These holes in the ground allow for water and other nutrients to enter the soil and nourish the remaining organisms. Trumpeter swans can also be a host to parasites including tapeworms, trematodes, and heart worms. (Cowan, 1946; Slater, 2006)

Commensal or parasitic species (or larger taxonomic groups) that use this species as a host

Do they cause problems?

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

How do they interact with us?

Historically, trumpeter swans were highly valued for their feathers and skins that were used for quill pens, arrows, and hat decorations. Today, trumpeter swans are protected under the United States Migratory Bird Act which makes hunting them illegal. (Slater, 2006)

  • Ways that people benefit from these animals:
  • body parts are source of valuable material

Are they endangered?

Historically, birds were heavily harvested for decorative feathers and skins. Althugh they are protected under the United States Migratory Bird Act, some are still hunted illegally. If birds are illegally shot or accidentally eat a lead bullet, they may suffer from lead poisoning which leads to death. Today, habitat destruction is likely the greatest threat to trumpeter swans. Humans have destroyed most of the wetland habitats that trumpeter swans live in. Efforts are being made to protect trumpeter swans and their wetland habitat, with many states (including Michigan) involved in reintroduction programs. Trumpeter swans are listed as threatened in the state of Michigan.

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. (Squires, 1995)

Contributors

Kaitlyn Robins (author), Radford University, Karen Powers (editor), Radford University, Rachelle Sterling (editor), Special Projects.

References

Baskin, Y. 1993. Trumpeter swans relearn migration. Bioscience, 43/2: 76-79.

Bergman, C. 1985. The Triumphant Trumpeter. National Geographic, 168/4: 544-558.

Cowan, I. 1946. Death of a Trumpeter Swan from Multiple Parasitism. The Auk, 63/2: 248-249.

Earnst, S. 1994. Tundra Swan Habitat Preferences during Migration in North Dakota. The Journal of Wildlife Management, 58/3: 546-551.

Grant, T., P. Henson. 1994. Feeding ecology of trumpeter swans breeding in south central Alaska. Journal of Wildlife Management, 58/4: 774.

Hanson, P., J. Cooper. 1994. Nocturnal Behavior of Breeding Trumpeter Swans. The Auk, 111/4: 1013-1018.

Henson, P., J. Cooper. 1993. Trumpeter Swan incubation in areas of differing food quality. Journal of Wildlife Management, 57/4: 709-716.

Johnsgard, P. 1978. The Triumphant Trumpeter. Natural History, 87/9: 72.

Kraft, F. 1946. The Flying Behemoth is Coming Back. Saturday Evening Post, 219/6: 6.

Krementz, D., R. Barker, J. Nichols. 1997. Sources of Variation in Waterfowl Survival Rates. The Auk, 114/2: 93-102.

LaMontagne, J., L. Jackson, R. Barclay. 2003. Characteristics of ponds used by trumpeter swans. Canadian Journal of Zoology, 81/11: 1791-1798.

Lynch, W. 2007. Perfection in White. Canadian Wildlife (Canadian Wildlife Federation), 13/4: 18-23.

Mills, J. 1991. The Swan That Would Not Fly. National Wildlife, 29/6: 4.

Proffitt, K. 2009. Trumpeter Swan Abundance and Growth Rates in Yellowstone National Park. Journal of Wildlife Management, 73/5: 728-736.

Schmidt, J., M. Lindberg, D. Johnson, J. Schmutz. 2009. Environmental and human influences of trumpeter swan habitat occupancy in Alaska. Condor, 111/2: 266/275.

Slater, G. 2006. "Trumpeter Swan (Cygnus buccinator): a technical conservation assessment" (On-line pdf). US Forest Service. Accessed February 16, 2010 at http://www.fs.fed.us/r2/projects/scp/assessments/trumpeterswan.pdf.

Squires, J. 1995. Trumpeter swan (Cygnus buccinator) food habits in the greater Yellowstone ecosystem. American Midland Naturalist, 133/2: 274.

Squires, J., S. Anderson. 1997. Changes in trumpeter swan (Cygnus buccinator) activities. American Midland Naturalist, 138/1: 208.

Truslow, F. 1960. Return of the Trumpeter. National Geographic, 118/1: 134.

Wilkinson, T. 1991. Call of the Trumpeter. National Parks, 66/7-8: 26.

 
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Robins, K. 2011. "Cygnus buccinator" (On-line), Animal Diversity Web. Accessed October 18, 2019 at http://www.biokids.umich.edu/accounts/Cygnus_buccinator/

BioKIDS is sponsored in part by the Interagency Education Research Initiative. It is a partnership of the University of Michigan School of Education, University of Michigan Museum of Zoology, and the Detroit Public Schools. This material is based upon work supported by the National Science Foundation under Grant DRL-0628151.
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