Cygnus buccinator, trumpeter swan
Tesky, Julie L. 1993. Cygnus buccinator, trumpeter swan. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: https://research.fs.usda.gov/feis/species-reviews/cybu
| Abbreviation | Common Name | Scientific Name | Classification | Status |
|---|---|---|---|---|
| Animals | ||||
| CYBU | trumpeter swan | Cygnus buccinator | Life Form: Animals/Bird Kingdom: Animalia Class: Bird Order: Anseriformes Family: Anatidae Genus: Cygnus | Fed. Protected: No Nativity: Native Invasiveness: Noninvasive |
Taxonomy
The currently accepted scientific name for the trumpeter swan is Cygnus buccinator Richardson [1,4,17]. There are no recognized subspecies or races.
Synonyms
- No entry
Other Common Names
None
General Distribution
Trumpeter swans were once abundant and widespread in North America. Their breeding range extended from Alaska east to Ontario and south to Oregon, the Rocky Mountains, Nebraska, and northern Missouri [20]. Now only two major populations remain [4,17,20]. The Pacific population breeds in Alaska and British Columbia, and winters along the Pacific Coast from Alaska to northern Oregon [20,23]. The mid-continental population nests in Alberta, British Columbia, Yukon, Northwest Territories, Saskatchewan, and the Greater Yellowstone region [20,23]. Overhunting of trumpeter swans destroyed most of their traditional migration patterns to southerly winter habitats. As a result, virtually all mid-continental trumpeter swans, regardless of their summer range, now winter in the Greater Yellowstone Ecosystem [23].
Trumpeter swans in a portion of the Green River on Seedskadee National Wildlife Refuge that remains open during the winter.
Trumpeter swans have been transplanted from Red Rock Lakes National Wildlife Refuge, Montana, to several other National Wildlife Refuges (NWR): Malheur NWR in Oregon, Ruby Lake NWR in Nevada, Lacreek NWR in South Dakota, and Turnbull NWR in Washington. A small number of breeding swans occur on all four refuges [4]. In Canada, attempts are underway to reintroduce trumpeter swans in southern Ontario and in Elk Island National Park [2].
States and Provinces
- United States: AK ID MT NV OR SD WA WY
- Canada: AB BC NT YK
- Mexico
Plant Communities
Trumpeter swans are generally found in wetland areas among aquatic and emergent vegetation. In Montana, they commonly build their nests in extensive beds of sedges (Carex spp.), bulrushes (Scirpus spp.), cattails (Typha spp.), and reeds (Juncus spp.). In Alaska, they use horsetails (Equisetum spp.) and sedges for nesting [4,10]. Plants found in most trumpeter swan habitats include willow (Salix spp.), alder (Alnus spp.), cottonwood (Populus spp.), water milfoil (Myriophyllum exalbescens), arrowhead (Sagittaria latifolia), and pondweed (Potamogeton spp.) [3,10].
Trumpeter swan family at Kenai National Wildlife Refuge, Alaska.
Biological Characteristics
Development and Reproduction
- Pair formation - Trumpeter swans most often form pair bonds when they are 2 or 3 years old, and first nest when they are 4 or 5 years old.
- Most pairs remain together year-round and bond for life [2,18,23].
- Nesting - In the Copper River area of Alaska, the Greater Yellowstone area, and Red Rock Lakes National Wildlife Refuge, egg laying normally begins in late April or early May and is completed about mid-May [4,17]. In interior Alaska, egg laying begins later than in the above areas [17]. In Alberta, the eggs are laid in mid-May [2].
- Clutch size and incubation - Each breeding pair uses only one nest and the female lays five to six eggs [2,14,17]. If the eggs are destroyed the pair will probably not renest [2]. The incubation period is 33 to 37 days [3,4,18].
- Cygnet development and fledging - Trumpeter swan cygnets grow rapidly [4]. They are fully feathered in 9 to 10 weeks, but are unable to fly until 13 to 15 weeks in Alaska and 14 to 17 weeks in Montana [4,17]. Cygnets remain with their parents throughout their first winter. They separate from their parents the following spring, but siblings may remain together into their third year. Family bonds are strong; subadult siblings may rejoin with parents after nesting ends or in subsequent winters [23].
- Molt - Nonbreeding subadults molt first. Most nonbreeders in Alaska begin their molt in late June or early July. At Red Rock Lakes, the molt may be completed as early as June [4]. It is rare for both members of a breeding pair to be flightless at the same time. The male of the pair usually molts first. Some paired birds may begin to molt as early as nonbreeders. Many, however, delay a month or longer. Some trumpeter swans are flightless until early September in Alaska and until October in Montana. Trumpeter swans are normally flightless for about 30 days [4].
- Migration - The seasonal movements of trumpeter swans in the Greater Yellowstone region are limited to local flights between breeding habitat and contiguous wintering areas. No molt migration is known. Breeders molt in the general vicinity of nesting territories [17]. In Alaska, trumpeter swan populations migrate south in shifts. This occurs from September until very late in the year, with times and distances varying depending on severity of the weather. Trumpeter swans move from interior regions in September, as total freeze-up occurs by the first week in October. By mid-October, they have usually left Kenai, located on the coast. On the Copper River Delta, many swans remain until about mid-November. They arrive at Lonesome Lake, British Columbia, beginning October 20 through October 25 [17].
- Life span - Trumpeter swans may live up to 35 years in captivity but usually do not live more than 12 years in the wild [2].
Predators
Predation is of little consequence in determining overall trumpeter swan population levels, but may be an important cause of death to preflight cygnets [3]. Except for man, trumpeter swans have few natural enemies after flying age is reached. Coyotes (Canis lutrans), river otters (Lutra canadensis), minks (Mustela vison), and golden eagles (Aquila chrysaetos) have been blamed for cygnet deaths in Yellowstone National Park and Red Rock Lakes National Wildlife Refuge [20]. The following species also occur in trumpeter swan habitat and could potentially prey on trumpeter swans: black bears (Ursus americanus), grizzly bears (U. arctos), lynx (Lynx canadensis), bald eagles (Haliaetus leucocephalus), great-horned owls (Bubo virgianus), mountain lions (Felis concolor), bobcats (Lynx rufus), striped skunk (Mephitis mephitis), red fox (Vulpes vulpes), raccoons (Procyon lotor), and gulls (Larus spp.) [20].
Habitat
Diet
Trumpeter swans eat the roots, stems, leaves, and/or seeds of a variety of aquatic vegetation, and they occasionally eat insects [2]. Initially, young cygnets eat large aquatic insects and snails. Cygnets feed on the water's surface and often depend on the adults to stir up the water around them. Within 2 to 3 weeks the cygnets start to eat aquatic plants [2].
Trumpeter swans feed on the following: the tubers of duck potato and sago pondweed (Potamogeton pectinatus); the stems and leaves of sago and other pondweeds (Potamogeton spp.), water milfoil (Myriophyllum verticullatum), muskgrass (Chara spp.), waterweed (Elodea canadensis), and duckweed (Lemna triscula); the seeds of yellow pond lily (Nuphar polysepala), water shield (Bransenia schreber), smartweed (Polygonum spp.), sedges (Carex spp.), and spikerush (Eleocharis spp.); and the stems and roots of grasses and sedges [2,3,4,17].
Preferred Habitat
Breeding habitat - Trumpeter swans nest on the margins of interconnected shallow marshes and lakes, lakes within forest or sagebrush habitat, and oxbows of rivers [18]. They prefer stable, quiet, shallow waters where small islands, muskrat houses, or dense emergent vegetation provide nesting and loafing sites. Nutrient-rich waters, with dense aquatic plant and invertebrate growth, provide the best habitat [3,23].
Nests are built in water 1 to 3 feet deep [4]. Trumpeter swans build a platform nest made of emergent vegetation. The nest is often located on a muskrat house, beaver lodge, or small island [18]. In Alaska, trumpeter swan nests are built 10 to 600 feet (3-183 m) from shore, depending upon cover and water depth. Occasionally, a nest is located on or near the shoreline of a small inlet in a large lake [10]. Winter habitat - Winter habitat must provide extensive beds of aquatic plants and water that remains ice-free. In the Greater Yellowstone region, cold temperatures and ice restrict trumpeter swans to sites where geothermal waters, springs, or outflow from dams maintain ice-free areas. In winter, trumpeter swans use shallow lakes, streams, and ponds that do not entirely freeze over during the winter months [18,23]. Pacific Coast trumpeter swans use both estuaries and freshwater habitats, and feed in pastures and croplands [23]. Good winter habitat also contains a certain amount of level and open terrain, allowing these large birds to loaf or fly without restriction of movement or visibility [3].
Cover Requirements
Tall emergent vegetation provides shelter and cover for trumpeter swans [10]. Adults may remove vegetation around the nest until the nest is surrounded by open water. This provides good visibility and protection from land predators [2]. During winter, trumpeter swans prefer open sites with few trees or shrubs to obscure their vision while feeding [23].
Fire-caused Mortality
Nonmolting adult trumpeter swans can probably easily escape fire. Molting adults, cygnets, and eggs are probably most susceptible to fire. During a 1969 summer fire at Kenai National Moose Range, Alaska, a trumpeter swan family with two cygnets was sighted in the water while spruce trees torched and went up in flames on the opposite shore. Despite heavy smoke, a pair of trumpeter swans with three cygnets was observed for several days on nearby Cow Lake during periods of active fire around the lake. This family moved away from the fire from one end of the lake to the other, but did not leave the lake even though the young had fledged. Nests of trumpeter swan at Mink Creek Lake and Beaver Lake were reestablished during the spring of 1970. Although their surroundings remained fire scarred, seven cygnets hatched at Mink Creek, and one hatched at Beaver Lake [9].
Fire Effects on Habitat
No specific information was found in the literature regarding fire-related effects on trumpeter swan habitat. Fire occurring in wetland habitats, however, often removes excessive accumulations of fast-growing hydrophytes, permitting better waterfowl access and growth of more desirable trumpeter swan foods such as pondweed and duckweed [19,21].
There may be some negative effects of burning waterfowl habitat. Large-scale autumn burning may have a detrimental effect upon marshes by reducing the retention of drifting snow. The ability of marsh vegetation to catch and hold snow is vital to marsh survival [22].
Fire Regimes
For fire regime information, search FEIS for this species by entering the species name or acronym on the home page and selecting “Fire Regime” as the publication type.
Fire Management Considerations
Prescribed burning is an effective method of manipulating waterfowl habitat [19]. Fire can be used to convert forested uplands adjacent to aquatic habitats to grasses and sedges, which are more suitable for trumpeter swan nesting [21]. Additionally, removal of dense vegetation and prevention of woody species encroachment is vital to prairie marsh maintenance [22]. Less dense vegetation allows more space for waterfowl activities [19]. Ward [22] reported that spring burning in marshlands is primarily done to remove vegetation and create more nesting edge for waterfowl. Summer fires are used to create more permanent changes in the plant community. Prescribed burning during the nesting season should be avoided so as not to disturb nesting females and/or destroy nests.
Federal Status
None
Other Status
Information on state- and province-level protection status of animals in the United States and Canada is available at NatureServe, although recent changes in status may not be included.
Other Management Information
The commercial swanskin trade, coupled with sport hunting and habitat destruction, reduced the species to near extinction by 1920. The trumpeter swans' traditional migration patterns and knowledge of important winter and spring habitats were lost as the swans neared extinction. Although recovery efforts have increased swan numbers, historic migratory paths have not yet been restored. As a result, virtually all the breeding trumpeter swans of Canada and the Greater Yellowstone Ecosystem share the same high-elevation winter habitat in the Greater Yellowstone Ecosystem. Increasing numbers of wintering swans, concentrating on this limited, harsh winter habitat are vulnerable to catastrophic losses. Reduced flows during drought, heavy ice formation, unusually severe winter weather, disease, or environmental pollution could destroy a large portion of the mid-continental population during a single winter [23].
Trumpeter swans are sensitive to human activities on their breeding grounds. Intrusions by humans at nesting wetlands have caused temporary and permanent nest abandonment as well as movements from breeding and staging areas [2,11]. Trumpeter swans will not nest on lakes intensively developed for recreation. The swans are most sensitive to disturbance from mid-April to mid-June [2].
Cygnet survival is associated with spring weather and favorable water levels. It is extremely important to properly manage water levels so that nest flooding is avoided and growth of aquatic vegetation is encouraged through nutrient cycling [18].
Management efforts currently focus on ensuring adequate stream flows, protecting and enhancing nesting and wintering habitat, and restoring southward migration to lower elevation habitats [23].
Table A1— Forest and range ecosystems, Bureau of Land Management (BLM) physiographic regions, Kuchler plant associations, Society for American Foresters (SAF) forest cover types, and Society for Rangeland Management (SRM) rangeland cover types in which this species occurs.
Forest and Range Ecosystems (Garrison et al. 1977)
- FRES23 Fir-spruce
- FRES24 Hemlock-Sitka spruce
- FRES26 Lodgepole pine
- FRES28 Western hardwoods
- FRES29 Sagebrush
- FRES36 Mountain grasslands
- FRES37 Mountain meadows
- FRES38 Plains grasslands
- FRES39 Prairie
BLM Physiographic Regions (Bernard and Brown 1977)
- 1 Northern Pacific Border
- 2 Cascade Mountains
- 5 Columbia Plateau
- 8 Northern Rocky Mountains
- 9 Middle Rocky Mountains
Kuchler Plant Associations (Kuchler 1964)
- K001 Spruce - cedar - hemlock forest
- K004 Fir - hemlock forest
- K008 Lodgepole pine - subalpine forest
- K015 Western spruce - fir forest
- K020 Spruce - fir - Douglas-fir forest
- K021 Southwestern spruce - fir forest
- K025 Alder - ash forest
- K063 Foothills prairie
- K064 Grama - needlegrass - wheatgrass
SAF Cover Types (Eyre 1980)
- 204 Black spruce
- 205 Mountain hemlock
- 217 Aspen
- 218 Lodgepole pine
- 222 Black cottonwood - willow
- 223 Sitka spruce
- 224 Western hemlock
- 225 Western hemlock - Sitka spruce
- 226 Coastal true fir - hemlock
- 227 Western redcedar - western hemlock
- 228 Western redcedar
- 235 Cottonwood - willow
- 253 Black spruce - white spruce
- 254 Black spruce - paper birch
SRM Rangeland Cover Types (Shiflet 1994)
- No entry
1. American Ornithologists' Union. 1983. Checklist of North American birds. 6th ed. Lawrence, KS: Allen Press, Inc. 877 p. [21234]
2. Anon. 1992. Alberta's threatened wildlife: Trumpeter swan. Alberta Forestry, Lands and Wildlife. Edmonton, AB: Alberta Fish and Wildlife Division, Nongame Management Program. 5 p. [21109]
3. Banko, W. E. 1960. The trumpeter swan: its history, habits, and population in the United S States. North American fauna 63. Washington, D. C: U.S. Fish and Wildlife Service. 214 p. [21575]
4. Bellrose, Frank C. 1980. Ducks, geese and swans of North America. Harrisburg, PA: Stackpole Books. 3rd ed. 540 p. [19802]
5. Bernard, Stephen R.; Brown, Kenneth F. 1977. Distribution of mammals, reptiles, and amphibians by BLM physiographic regions and A.W. Kuchler's associations for the eleven western states. Tech. Note 301. Denver, CO: U.S. Department of the Interior, Bureau of Land Management. 169 p. [434]
6. Eyre, F. H., ed. 1980. Forest cover types of the United States and Canada. Washington, DC: Society of American Foresters. 148 p. [905]
7. Finch, Deborah M. 1992. Threatened, endangered, and vulnerable species of terrestrial vertebrates in the Rocky Mountain Region. Gen. Tech. Rep. RM-215. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Forest and Range Experiment Station. 38 p. [18440]
8. Garrison, George A.; Bjugstad, Ardell J.; Duncan, Don A.; [and others]. 1977. Vegetation and environmental features of forest and range ecosystems. Agric. Handb. 475. Washington, DC: U.S. Department of Agriculture, Forest Service. 68 p. [998]
9. Hakala, John B.; Seemel, Robert K.; Richey, Robert A.; Kurtz, John E. 1971. Fire effects and rehabilitation methods--Swanson-Russian Rivers fires. In: Slaughter, C. W.; Barney, Richard J.; Hansen, G. M., eds. Fire in the northern environment--a symposium: Proceedings of a symposium; 1971 April 13-14; Fairbanks, AK. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Range and Experiment Station: 87-99. [15721]
10. Hansen, H. A.; Shepard, P. E. K.; King, J. G.; Troyer, W. A. 1971. The trumpeter swan in Alaska. Wildlife Monograph. 26: [19664]
11. Henson, Paul; Grant, Todd A. 1991. The effects of human disturbance on trumpeter swan breeding behavior. Wildlife Society Bulletin. 19(3): 248-257. [19313]
12. Johnsgard, Paul A. 1979. A guide to North American waterfowl. Bloomington, IN: Indiana University Press. 274 p. [20026]
13. Kortright, Francis H. 1942. The ducks, geese and swans of North America. Harrisburg, PA: The Stackpole Company; Washington, DC: Wildlife Management Institute. 476 p. [21240]
14. Madge, Steve; Burn, Hilary. 1988. Waterfowl: An identification guide to the ducks, geese and swans of the world. Boston, MA: Houghton Mifflin Company. 298 p. [20029]
15. Montana Natural Heritage Program. 1990. Animal species of special concern. Helena, MT: Montana Natural Heritage Program. 5 p. [13751]
16. Moseley, Robert; Groves, Craig, compilers. 1990. Rare, threatened and endangered plants and animals of Idaho. Boise, ID: Idaho Department of Fish and Game, Nongame and Endangered Wildlife Program, Natural Heritage Section. 33 p. [19328]
17. Palmer, Ralph S., editor. 1976. Handbook of North American birds. vol. 2. New Haven, CT: Yale University Press. 521 p. [21242]
18. Reel, Susan; Schassberger, Lisa; Ruediger, William, compilers. 1989. Caring for our national community: Region 1 - threatened, endangered & sensitive species program. Missoula, MT: U.S. Department of Agriculture, Forest Service, Northern Region. 309 p. [19675]
19. Schlichtemeier, Gary. 1967. Marsh burning for waterfowl. In: Proceedings, 6th annual Tall Timbers fire ecology conference; 1967 March 6-7; Tallahassee, FL. No. 6. Tallahassee, FL: Tall Timbers Research Station: 40-46. [16450]
20. Shea, R. E. 1979. The ecology of the trumpeter swan in Yellowstone National Park and vicinity. Missoula, MT: University of Montana. 132 p. Thesis. [21577]
21. Vogl, Richard J. 1967. Controlled burning for wildlife in Wisconsin. In: Proceedings, 6th annual Tall Timbers Fire Ecology Conference; 1967 March 6-7; Tallahassee, FL. No. 6. Tallahassee, FL: Tall Timbers Research Station: 47-96. [18726]
22. Ward, P. 1968. Fire in relation to waterfowl habitat of the delta marshes. In: Proceedings, annual Tall Timbers fire ecology conference; 1968 March 14-15; Tallahassee, FL. No. 8. Tallahassee, FL: Tall Timbers Research Station: 255-267. [18932]
23. Clark, Tim W.; Harvey, Ann H.; Dorn, Robert D.; [and others], eds. 1989. Rare, sensitive, and threatened species of the Greater Yellowstone Ecosystem. Jackson, WY: Northern Rockies Conservation Cooperative, Montana Natural Heritage Program, The Nature Conservancy, Mountain West Environmental Services. 153 p. [16007]
24. U.S. Department of the Interior, Fish and Wildlife Service. 2013. Endangered Species Program, [Online]. Available: http://www.fws.gov/endangered/. [86564]
25. Committee on the Status of Endangered Wildlife in Canada. 1992. Canadian species at risk. Ottawa, ON. 10 p. [26183]