Название:Do Hummingbirds Hum?: Fascinating Answers to Questions About Hummingbirds (Animal Q&a Series) Автор: George C. West, Carol A. Butler Издательство: Rutgers University Press Год издания: 2010 isbn: 0813547385 Количество страниц: 208 Формат: PDF Размер: 2 Мб Язык: english 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.
The Status of Birds in Britain and Ireland скачать
Название: The Status of Birds in Britain and Ireland Автор: Alan Knox and David T. Parkin Издательство: Christopher Helm Год: 2010 Страниц 472 ISBN: 1408125005 Формат: PDF Размер: 12,2 MB Язык Английский The Status of Birds in Britain and Ireland