The trumpeter swan  is the heaviest living bird native to North America, it is also the largest extant species of waterfowl with a wingspan that may exceed 10 ft. It is the American counterpart and a close relative of the whooper swan 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.
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