[Tweeters] Bobbing

[via Tweeters]

A group of us birding at Juanita Bay Park in Kirkland on December 29 enjoyed observing a Wilson’s snipe bobbing away. We were interested in learning more about bobbing as an evolutionary adaptation. The head appears to stay level while the body bobs. One of our group found references in Birds of the World postulating enhanced visual and depth perception, improved balance, avoidance of predation, and stimulating movement of prey in the mud. Can anyone offer further explanation regarding the above possibilities? Or offer other explanations? Thanks.