Jun 9, 2009 1:22 PM

The hummingbird that's faster than a fighter jet

A scientist has caught a hummingbird hitting a top speed twice that of the fastest fighter jet – at least relatively.

The Anna’s hummingbird, now believed to be the fastest bird in the world relative to its size, can reach speeds of 50mph, or nearly 385 body lengths per second. That may seem slow compared with a Eurofighter's top speed of 1,320mph, but even at that speed the jet manages to cover just 39 body lengths per second.

Christopher Clark of UC Berkeley said the bird reached 10-G acceleration as it pulled out of its dive, greater than previously reported accelerations "for any organism undergoing aerial manoeuvres, except jet fighter pilots," says Clark.

The bird's display of aeronautical prowess – not to mention that of a figher pilot – is all to impress the ladies.

To get the male birds to dive, Clark placed a stuffed model hummingbird, or a live hummingbird in a cage, near a male’s perch. He then filmed close-up, high-speed videos of diving birds to record the bird’s wing and tail kinematics over the course of the dive. Sounds produced by the bird’s wings and tail were also recorded using a microphone.

Clark carried out the research at Albany Bulb in the East Shore State Park, California, a site he chose because it helped him film the high-speed birds. "This location is at sea level, and was flat and relatively devoid of obstructing topographic features, facilitating the collection of video in which diving birds were a few dark pixels silhouetted against the sky," he explained in a paper published by the Proceedings of the Royal Society B: Biological Sciences.

He found that the dive consisted of five stages. In the first, the birds descended into view, propelling themselves earthward by flapping their wings. Then they stopped flapping, tucked their wings by their sides, and stop making noise. The birds next spread their wings to glide before going into stage four, when they abruptly spread their tails at the bottom of the dive. Finally, they flapp their wings once and shut their tails for the final stage of the dive.

The second stage is the fastest. Clark writes: "After powering the initial stage of the dive by flapping, males folded their wings by their sides, at which point they reached an average maximum velocity of 385 body lengths per second." This is faster than a diving peregrine falcon as well as fighter jets.

While the speed is what impressed the researcher, he believes it's the loudness of the sound produced by the tail feathers during stage four of the process that attracts the female birds. The faster the bird flies, the louder the sound becomes, which explains the Anna’s hummingbird’s need for speed.

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This article was originally published by WIRED UK