Wagon-wheel effect makes bird magically float

Date:20 July 2017 Author: Nikky Knijf Tags:, , , , ,

At first glance the bird floating in front of a security camera is eerie and quite confusing. But this bird is not floating at all. It’s wing flapping speed is just equal to the frame rate of the security camera. This results in the wagon-wheel effect.

This video was captured by Texas homeowner Al Brooks. When reviewing the footage Brooks noticed the bird moving bizarrely in front of the camera. Brooks commented he slowed down the video a little to make it easier to see the bird, but promises he didn’t edit it and that the bird is real. Here’s what happened:

At first the bird enters the frame slowly with its wings in an upward position. The wings are then slowly brought down as the bird moves into the frame. Once in the frame, the bird appears to be hovering in front of the camera with its wings downward. In this case it’s not your brain imagining things, but frame-rate of the camera. See, the bird is flapping its wings to stay in the air, but the camera’s frame-rate of the same speed makes it look like the bird is floating.

The wagon-wheel effect is an optical illusion where the spokes of a wheel – or in this case wings of the bird – appears to move or rotate slowly or not at all. The term wagon-wheel effect was coined from Western movies where wagon wheel spokes were only seen intermittently. It’s most often seen with airplane propellers, rotary-wing aircraft and car wheels.

And in case you were wondering, Brooks’ camera is a HIKVISION’s DS-2CD2342WD-I, with a resolution of 2688×1520 (slightly higher than 4MP). The frame-rate is 20 FPS. Yes, we know: flaps per second.

Video and image credit: Al Brooks

Source: SwissMiss via This is Colossal




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