Male hummingbirds, swooping in an effort to impress females, achieve speeds "faster than fighter jets", according to a study.
A US researcher has captured the birds' dives with super-fast cameras. He lured them into their impressive displays using stuffed models of female birds.
The feathered acrobats reached speeds of almost 400 body lengths per second.
The findings are reported in the journal Proceedings of the Royal Society B.
Christopher Clark from the University of California Berkeley filmed the courtship dives of male Anna's hummingbirds on cameras able to capture 500 frames per second.
When measured relative to the length of their bodies, the birds' top speed, he said, was "greater than [that] of a fighter jet with its afterburners on, or the space shuttle during atmospheric re-entry".
Jet fighters, however, are able to out-accelerate the little birds.
In the latter stages of their dives, when they spread their wings to pull up, the hummingbirds' "instantaneous acceleration" was, said Mr Clark, "greater than any organism previously recorded undergoing aerial manoeuvres".
And that was all without the help of a powerful jet engine.
The study, Mr Clark said, was an example of how such displays, triggered by the prospect of a mate, could be used to study the very limits of animals' abilities.