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Автор: George C. West, Carol A. Butler
Издательство: Rutgers University Press
Год издания: 2010
isbn: 0813547385
Количество страниц: 208
Язык: english
Формат: PDF
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Hummingbirds may be the smallest birds in the world, but they have the biggest appetites. Their wings flutter on average fifty to eighty times each second as they visit hundreds of flowers over the course of a day to sip the sweet nectar that sustains them. Their hearts beat nearly twelve hundred times a minute and their rapid breathing allows these amazing birds to sustain their unique manner of flight. They can hover in the air for prolonged periods, fly backwards using forceful wings that swivel at the shoulder, and dive at nearly two hundred miles per hour. Native only to the Americas, some hummingbirds have been known to migrate from Mexico to Alaska in the course of a season. Watching a hummingbird at a backyard feeder, we only see its glittering iridescent plumage and its long, narrow beak; its rapidly moving wings are a blur to our eyes. |
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