When a male hummingbird is courting a female, he'll do some insane aerial moves to show her how strong, controlled and just generally fantastic he is. On occasion, if the female enjoys the show, she'll starting moving in the air with him. This can sometimes look like they're actually mating in the air, because they can get very close. In fact, hummingbirds often get right up in each other's faces. Male hummingbirds will do a sort of "dance off" when fighting over territory, and several hummingbirds will get together to chase off an outsider.
Appearances aside, hummingbirds don't actually mate in midair. Their legs may not be able to walk or bounce, but they can perch. Hummingbirds are able to stand on branches, and that's where they copulate. After a female accepts a talented suitor, she'll perch on a branch and wait for the male to mount her from behind. About four seconds later, they leave each other and never look back [source: World of Hummingbirds]. The male goes to look for another female to mate with, and the female goes off to build a nest.
Probably the most fascinating part of the mating ritual is the initial courtship activity. Males go to serious lengths to impress females. A male hummingbird will dance and sing. He'll perform what's referred to as a courtship dive, which seems like a scary display but seems to go far with the hummingbird ladies. Flying up to 60 feet (18.28 meters) in the air, the male bird will suddenly arc and head straight down, flying in a beeline for the female [source: World of Hummingbirds]. When he's within inches of her head -- still at full speed -- he'll pull up, flying back to 60 feet and starting all over again. When the female is suitably impressed with the dive, she'll go wait on a perch.
Female hummingbirds are picky about their mates. It can sometimes get to be quite a competition. Male hummingbirds have been known to get together and serenade a female, each trying to win her attention. When she does show attention to one of the males, the courtship dive or other midair dances begin, and the other birds give up and fly away.
Just because hummingbirds don't mate in midair, though, doesn't mean nobody does. White-throated swifts, birds native to the American West, sometimes copulate while falling through the air of a canyon [source: Stanford]. A pair of great gray garden slugs will also mate in midair -- while hanging from a cord of slime [source: OSU].
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