Trumpeter swan (Cygnus buccinator)

Description

What’s the World’s Favourite Species?

Trumpeter swan fact file

• Description
• Biology
• Range
• Habitat
• Status
• Threats
• Conservation
• Find out more
• Glossary
• References
• Print factsheet

Trumpeter swan description

The largest waterfowl species in North America ^{(2) (3)}, the trumpeter swan (Cygnus buccinator) is named for its distinctive, trumpeting, ‘oh-OH’ call ⁽³⁾. Both the male and female trumpeter swan are entirely white, with a black bill, face and legs, and a long, straight neck ^{(2) (3)}. The male trumpeter swan is slightly larger than the female ⁽³⁾.

Juvenile trumpeter swans are also mostly white, but may have some darker grey or greyish-brown feathers and more greyish-pink legs, which turn yellowish-grey to black with age ^{(2) (3)}. On hatching, young trumpeter swans, called cygnets, are normally grey, with greyish-pink feet and a greyish-black to dull pink bill ⁽³⁾.

The trumpeter swan is very similar in appearance to the tundra swan (Cygnus columbianus), and the two species can be difficult to tell apart. However, the trumpeter swan is larger, with a longer neck, and also differs slightly in the shape and profile of its bill. In addition, the tundra swan often has a yellow spot in front of the eyes, which is lacking in the trumpeter swan ^{(2) (3)}.

Size

Length: 138 - 158 cm ⁽²⁾

Wingspan: 203 cm ⁽²⁾

Weight

7 - 13.6 kg ⁽³⁾

Trumpeter swan biology

The trumpeter swan feeds mainly on plants, including the leaves, stems, roots and tubers of submerged and emergent vegetation, often supplemented with grasses and small grains ^{(2) (3) (4)}. Very occasionally, the trumpeter swan may eat fish or fish eggs, and the cygnets often consume aquatic invertebrates ⁽³⁾.

As well as foraging by touch and by sight, on and below the water, the trumpeter swan may dig in soil when looking for foods such as tubers ⁽³⁾. Like many other waterfowl species, it often feeds at night, particularly in winter ⁽⁵⁾. The trumpeter swan feeds at a particularly high rate during spring, to build up its reserves prior to nesting ⁽⁵⁾.

Migratory trumpeter swans typically return to their northern breeding grounds between February and March ⁽³⁾. A monogamous species, the trumpeter swan may form a pair bond with a mate from about 20 months old, although most bonds do not develop firmly until about 3 or 4 years of age. A pair will often inhabit a wetland area for several years before eventually nesting there ⁽³⁾. The breeding pair stays together throughout the year and usually mates for life, although some individuals have been known to ‘divorce’ their mate and be serially monogamous. Some males never pair again after the death of a mate ^{(2) (3)}.

The breeding season of the trumpeter swan can vary widely both by region and with weather patterns. However, most egg-laying takes place between late April and May ⁽³⁾. Both the male and female trumpeter swan help build the nest, which consists of a large, open bowl of aquatic vegetation, grasses and sedges, lined with feathers, and usually located on a slightly elevated site surrounded by water ^{(2) (3)}. The trumpeter swan is territorial when breeding, and may attack intruding swans, as well as other species ⁽³⁾.

The trumpeter swan lays up to 9 creamy-white eggs, which are incubated, mainly by the female, for 32 to 37 days. The young swans are able to leave the nest within a day of hatching, and are capable of swimming and feeding themselves ^{(2) (3)}. The young are able to fly after about 84 to 122 days ⁽³⁾. In migratory populations, the trumpeter swans usually move south in September or October, although some individuals stay until the water freezes in November ⁽³⁾.

The trumpeter swan is relatively long-lived, surviving for up to 24 years in the wild or over 32 years in captivity ^{(2) (3)}.

Trumpeter swan range

The trumpeter swan breeds from central and southern Alaska, through parts of Canada and into the northern United States. This species is present year-round in much of its range, but some populations migrate southwards to ice-free waters in winter, when they can be found as far south as Arkansas and Texas ^{(2) (3)}.

Reintroduction efforts have expanded the range of the trumpeter swan in many areas, and it can now be seen wintering almost anywhere in the continental United States ⁽³⁾.

Trumpeter swan habitat

The trumpeter swan inhabits a variety of freshwater habitats, particularly ponds, marshes and lakes, and occasionally rivers ^{(2) (3)}. It tends to avoid water bodies that are stagnant or overly acidic ⁽³⁾.

When choosing a nesting ground, the trumpeter swan selects sites with enough space to take off, as well as accessible food, shallow, unpolluted water, and little or no human disturbance. It also requires a suitable structure to nest on, such as a clump of emergent vegetation, an island, or an old beaver lodge ^{(2) (3)}.

Trumpeter swan status

The trumpeter swan is classified as Least Concern (LC) on the IUCN Red List ⁽¹⁾.

Trumpeter swan threats

This large swan was reduced to near extinction in the early 20th century, primarily as a result of hunting for its skins and for its feathers, which were used to make quill pens ^{(2) (3)}. The cygnets were also hunted for meat. By 1935, only 69 trumpeter swans were known to exist, although unrecorded flocks also remained in parts of Alaska and Canada ⁽³⁾.

Fortunately, conservation measures have since allowed the trumpeter swan to make a dramatic comeback, and its numbers and distribution are steadily increasing ⁽³⁾. However, this species still faces a number of threats, including collisions with power lines, fences and other man-made structures, as well as habitat loss, habitat alteration and disease. The trumpeter swan is also susceptible to lead poisoning as, despite lead being banned in waterfowl hunting for decades, old lead sinkers and lead shot have ended up in sediments that the swans sift through when looking for food ^{(3) (6)}.

Although hunting of trumpeter swans is now illegal throughout North America, illegal shooting does sometimes occur. The trumpeter swan is also easy to mistake for the tundra swan (Cygnus columbianus), which is legal to hunt, and thus may be accidentally killed or wounded by hunters ^{(3) (6)}.

Human disturbance poses a more indirect threat to the trumpeter swan, particularly around its nesting sites ^{(3) (7)}. Such disturbance can come in the form of aircraft noise, traffic, or the presence of humans near the nest, with the presence of humans having the greatest effect on the swans ⁽⁷⁾. The trumpeter swan’s first response to humans in the nesting area is to leave, which can cause the swans to forgo suitable nesting sites or not nest at all. Disturbance can also cause the trumpeter swan to abandon the nest, increasing the risk of egg and chick mortality due to exposure or predation ⁽⁷⁾.

Trumpeter swan conservation

The dramatic recovery of the trumpeter swan is often considered a conservation success story, as this species has responded well to a range of conservation and management measures. These include habitat conservation, protection from shooting, and programmes to expand this species’ range by translocating individuals to new areas ^{(3) (6)}. The trumpeter swan is currently protected under the Migratory Bird Treaty Act, and hunting of this species is illegal in North America ⁽³⁾.

One of the most important conservation measures for the trumpeter swan is ensuring that it has adequate habitat, both for wintering and breeding. Habitat restoration, including efforts to reduce lead pollution, manage water levels and promote the growth of aquatic plants, has greatly contributed to the trumpeter swan’s recovery, and measures to minimise human disturbance have also been recommended ^{(3) (7)}.

Despite the overall increase in the trumpeter swan population, some flocks are still vulnerable to a range of threats, and need to be managed on an individual basis. In addition, further research is needed into the trumpeter swan’s biology, behaviour, life history and migratory patterns, to aid in appropriate management decisions ⁽³⁾. However, the trumpeter swan population as a whole has rebounded spectacularly, and is a prime example of how a species can be brought back from the brink of extinction if the right conservation measures are taken ⁽³⁾.

Find out more

Find out more about the trumpeter swan and its conservation:

• BirdLife International - Trumpeter swan:
  http://www.birdlife.org/datazone/speciesfactsheet.php?id=370
• Birds of North America Online - Trumpeter swan (Cygnus buccinator):
  http://bna.birds.cornell.edu/bna/species/105/

More information on bird conservation in North America:

• American Bird Conservancy (ABC):
  http://www.abcbirds.org/

Authentication

This information is awaiting authentication by a species expert, and will be updated as soon as possible. If you are able to help please contact:
arkive@wildscreen.org.uk

Glossary

Emergent

Aquatic plants whose stems and leaves extend beyond the water’s surface.

Incubate

To keep eggs warm so that development is possible.

Invertebrates

Animals with no backbone, such as insects, crustaceans, worms, molluscs, spiders, cnidarians (jellyfish, corals, sea anemones) and echinoderms.

Monogamous

Having only one mate during a breeding season, or throughout the breeding life of a pair.

Territorial

Describes an animal, a pair of animals or a colony that occupies and defends an area.

Translocation

When individual living organisms from one area are transferred and released or planted in another area.

Tuber

In plants, a thickened stem or root that acts as an underground storage organ. Roots and shoots grow from growth buds, called ‘eyes’, on the surface of the tuber.

References

1. IUCN Red List (June, 2011)
   http://www.iucnredlist.org/
2. The Cornell Lab of Ornithology: All About Birds - Trumpeter swan (August, 2011)
   http://www.allaboutbirds.org/guide/Trumpeter_Swan
3. Mitchell, C.D. and Eichholz, M.W. (2010) Trumpeter swan (Cygnus buccinator). In: Poole, A. (Ed.) The Birds of North America Online. Cornell Lab of Ornithology, Ithaca. Available at:
   http://bna.birds.cornell.edu/bna/species/105/
4. Squires, J.R. and Anderson, S.H. (1995) Trumpeter swan (Cygnus buccinator) food habits in the greater Yellowstone ecosystem. American Midland Naturalist, 133(2): 274-282.
5. Squires, J.R. and Anderson, S.H. (1997) Changes in trumpeter swan (Cygnus buccinator) activities from winter to spring in the greater Yellowstone area. American Midland Naturalist, 138(1): 208-214.
6. Engelhardt, K.A.M., Kadlec, J.A., Roy, V.L. and Powell, J.A. (2000) Evaluation of translocation criteria: case study with trumpeter swans (Cygnus buccinator). Biological Conservation, 94(2): 173-181.
7. Henson, P. and Grant, T.A. (1991) The effects of human disturbance on trumpeter swan breeding behavior. Wildlife Society Bulletin, 19(3): 248-257.