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The trumpeter swan (''Cygnus buccinator'') is a species of swan found in North America. The heaviest living bird native to North America, it also is on average, the largest extant species of waterfowl with a wingspan that may exceed . It is the American counterpart and a close relative of the whooper swan (''Cygnus cygnus'') of Eurasia, and even has been considered the same species by some authorities. By 1933, fewer than 70 wild trumpeters were known to exist, and extinction seemed imminent, until aerial surveys discovered a Pacific population of several thousand trumpeters around Alaska's Copper River. Careful reintroductions by wildlife agencies and the Trumpeter Swan Society gradually restored the North American wild population to over 46,000 birds by 2010.〔 ==Description== The trumpeter swan is the largest extant species of waterfowl. Adults usually measure long, though large males can exceed in total length.〔〔 The weight of adult birds is typically . Possible due to seasonal variation based on food access and variability due to age, average weights in males have been reported to range from and from in females.〔〔Drewien, R.C., & Bouffard, S.H. (1994). Winter body mass and measurements of Trumpeter Swans ''Cygnus buccinator''. ''Wildfowl'' 45(45):22-32.〕〔Sparling, D.W., Day, D., & Klein, P. (1999). ''Acute toxicity and sublethal effects of white phosphorus in mute swans, Cygnus olor''. Archives of environmental contamination and toxicology, 36(3), 316-322.〕〔James, M.L. (2000). Status of the trumpeter swan (''Cygnus buccinator'') in Alberta. Alberta Environment, Fisheries & Wildlife Management Division, Resource Status and Assessment Branch.〕 It is one of the heaviest living birds or animals capable of flight. Alongside the mute swan (''Cygnus olor''), Dalmatian pelican (''Pelecanus crispus'') and Andean condor (''Vultur gryphus'') and the kori bustard (''Ardeotis kori''), it is one of the handful to scale in excess of between the sexes and one survey of wintering trumpeters found it averaged second only to the condor in mean mass.〔Dunning, Jr., John B. (Editor). (2008). ''CRC Handbook of Avian Body Masses, 2nd Edition.'' CRC Press. ISBN 978-1-4200-6444-5.〕〔Greenwood, J.J., Gregory, R.D., Harris, S., Morris, P A., & Yalden, D.W. (1996). Relations between abundance, body size and species number in British birds and mammals. ''Philosophical Transactions of the Royal Society of London. Series B: Biological Sciences'' 351(1337):265-278.〕 The trumpeter swan's wingspan ranges from , with the wing chord measuring .〔〔〔〔(【引用サイトリンク】title=Trumpeter Swan video, photos and facts )〕 The largest known male trumpeter attained a length of , a wingspan of and a weight of . It is the second heaviest wild waterfowl ever found, as one mute swan was found to weigh a massive , but it has been stated that was unclear whether this swan was still capable of flight due to its bulk. The adult trumpeter swan is all white in plumage. Like mute swans cygnets, the cygnets of the trumpeter swan have light grey plumage and pinkish legs, and gain their white plumage after about a year. As with a whooper swan, this species has upright posture and generally swims with a straight neck. The trumpeter swan has a large, wedge-shaped black bill that can, in some cases, be minimally lined with salmon-pink coloration around the mouth. The bill, measuring , is up to twice the length of a Canada goose's (''Branta canadensis'') bill and is the largest of any waterfowl. The legs are gray-pink in color, though in some birds can appear yellowish gray to even black. The tarsus measures . The mute swan, introduced to North America, is scarcely smaller. However, it can easily be distinguished by its orange bill and different physical structure (particularly the neck, which is always curved down as opposed to straight in the trumpeter). The mute swan is often found year-around in developed areas near human habitation in North America, whereas trumpeters are usually only found in pristine wetlands with minimal human disturbance, especially while breeding.〔 The tundra swan (''C. columbianus'') more closely resembles the trumpeter, but is significantly smaller. The neck of a male trumpeter may be twice as long as the neck of a tundra swan.〔 The tundra swan can be further distinguished by its yellow lores. However, some trumpeter swans have yellow lores; many of these individuals appear to be leucistic and have paler legs than typical trumpeters. Distinguishing tundra and trumpeter swans from a distance (when size is harder to gauge) can be challenging without direct comparison but it is possible thanks to the trumpeter's obviously longer neck (the great length of which is apparent even when the swan is not standing or swimming upright) and larger, wedge-shaped bill as compared to the tundra swan. Trumpeter swans have similar calls to whooper swans and Bewick's swans. They are loud and somewhat musical creatures, with their cry sounding similar to a trumpet, which gave the bird its name. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Trumpeter swan」の詳細全文を読む スポンサード リンク
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