Here's the thing about hummingbirds: Almost nothing they do is like a regular bird. A hummingbird's heart beats about 1,200 times a minute while exercising.

When hovering, their wings flap around about 100 times a second. So when Alejandro Rico-Guevara, who studies evolutionary biology and ecology at UConn, wanted to capture male hummingbirds fighting over potential mates in groupings called "leks," he recorded them with a high-speed camera, and then slowed the tape way down.

That's when he discovered something interesting inside each chirp:

"People haven’t paid that much attention to hummingbird songs, because they don’t seem complex or interesting," Rico-Guevara said. "But now that we have the tools … we’re trying to study all the different calls from different males. We’re finding they vary a lot. Maybe that source of variation is what females are selecting upon."

To see a video of the hummingbird call, visit WNPR's Science Blog, The Beaker.