Thursday, March 22, 2012

What is this avocet eating?

American  Avocets feed  by walking through the water and waving their beaks side to side.
Rarely can yousee what it is they are catching.  It's easy to assume that they roil the mud
and grab little critters that are buried.  But not this bird.  It actually caught a wriggling fish.
Slow-motion video shows it pretty clearly. Stop action  shows even more.  The last few
frames are sequential stills.  As the bird shifts the slippery fish closer to its mouth, it can
keep the tip relatively closed.  Notice near the end that the tip is actually  more
tightly closed than the base, and the base of the maxilla (upper jaw) bows upward to
accomodate the fish. This is exactly like a pair of jointed human fingers would have done
 the job. Quite a versatile tool.  And to think that old Count Buffon considered the avocet's
beak to be a degeneration.
To see this clip in high definition

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