Hummingbirds can hover in place for minutes at a time, fly backward, and flap their wings up to 70 times per second. They also have bizarre courtship rituals.
The details vary among species, but the principles are basically the same: The male hovers in front of the female, singing and flexing feathers on his throat to form a bright mask. In Costa’s hummingbird, this display resembles a brilliant purple six-armed octopus.
Then the would-be suitor flies as high as 100 feet into the sky, tucks his legs into his body, and dives head first toward the ground at speeds of 60 miles per hour before looping back up. He might repeat this dive bomb between three and 20 times.
From the perspective of the female hummingbird, the suitor would look like a small comet hurtling through the sky with sunlight glinting off his iridescent head feathers.
But there’s more: an audio component. Male hummingbirds have evolved special elongated tail feathers that make noise by vibrating during the descent. “The physics of how the feathers are making a sound is like the strings of an instrument,” said Chris Clark, a professor of biology at UC Riverside. “Thick, heavy feathers make low sounds, and thinner, lighter strings make higher-pitched sounds.”