After a few weeks of being fed piles of gooey bugs by its parents, a newly hatched swift will suddenly drop from the nest, open its wings, become airborne and will not land again for the next three years. Yes, you read that right. Once a young swift leaves the nest it will continue to fly, nonstop, for three years. Common swifts eat, drink, bathe, sleep (really) and, yes, mate entirely on the wing. In fact, these birds were members of the Mile High Club centuries before Richard Branson made it fashionable.