Show Details

Pigeon Illusions

September 14, 2010

A listener asks: Why do pigeons bob their heads back and forth when they walk?

Transcript

BOB HIRSHON (host):
A fancy pigeon trickā€¦I’m Bob Hirshon and this is Science Update.

Listener Hang-Kwan Wu of Walnut Creek, California wants to know why pigeons bob their heads back and forth when they walk. We asked neuroscientist Niko Troje of Queens University in Canada. He says the head-bobbing is a actually a visual illusion.
NIKO TROJE (Queens University):
The head does make sudden forward movements, but it never moves back.
HIRSHON:
He says the pigeon’s head stays briefly locked in space while its body catches up. This helps the bird spot small, moving insects on the ground, which would be harder if it were constantly moving its head as it walked. He says mammals move just their eyes to get a similar effect, but many birds move their entire head.
TROJE:
Turns out that the image stabilization obtained by fixating the head is a little more accurate than the one you would obtain with eye movements.
HIRSHON:
And if you have a science question, give us a call at 1-800-why-isit. I’m Bob Hirshon, for AAAS, the science society.