Dan Logen wrote:
> I was watching a Western Sandpiper through my scope a few weeks ago and was
> shocked to see it raise the distal third of its upper mandible up at an
> angle of about 30 degrees.

Nice careful observation, Dan! I don't think you're alone in having believed
sandpipers open their entire bills to grasp prey. I would still believe that
myself if I hadn't had a chance to "play" with a Western Sandpiper bill a few
years ago.

I was at Bottle Beach looking for oiled shorebirds after the _Nestucca_ spill
off Grays Harbor when a Merlin came through and, predictably, scared up a ball
of shorebirds. I wore myself out holding up binoculars while that Merlin tried
and failed repeatedly to snag a bird. Eventually, it was successful and carried
prey to a piling for plucking.

I kept my distance till the meal was done and the Merlin flew off. I then
walked to the piling to see what might remain of its prey. I found crimson
spatterings on piling-attached algae and just a head on the mud below.

On the ride home, I studied the Western Sandpiper head and fiddled with its
bill. I was amazed when I lifted the tip a bit and the upper mandible "folded"
upward, leaving the rest of the bill closed. After a little thought, I realized
that's an obvious adaptation for a shorebird; why push any more mud or sand
than necessary out of the way when grasping buried prey? Imagine a dowitcher or
godwit or other long-billed shorebird attempting to open its deeply-probing
bill just to open and close over a morsel at the far end. The articulation
makes the job a lot easier!

I don't know what other species share this feature, but it's a cool thing to
know about and probably a difficult thing to see in action.

It also doesn't last in a dead bird. By the time I brought that sandpiper head
to the museum a few days later, the bill had become rigid.
--
Scott Richardson
Olympia, Washington
salix at halcyon.com
http://www.halcyon.com/salix/oiled.htm