On 31 March, we watched a Common Raven (Corvus corvax) actively digging for Mole Crabs (Emerita analoga) at low tide — and I mean actively!
The raven used its large bill to fling sand to either side (note the airborne clumps of sand):
Sometimes it would use its open bill to pick up or push aside large volumes of sand:
The depth of the pits was impressive. After the raven had left the area, we measured several pits. They were between 8-10 cm (3-4 inches) deep!
Occasionally the raven would pull a Mole Crab out of a pit. Some of the crabs were manipulated at the surface before being eaten:
Other crabs were swallowed whole (see below). Recently we had noticed quite a few soft-shelled Mole Crabs, i.e., crabs that have molted. We wondered if the raven was choosing to swallow the soft-shelled crabs and to pick apart the hard-shelled crabs?
One more image of this handsome bird, with its sand-covered bill hinting at this intriguing feeding behavior. How do the ravens know how to find the crabs? Is it a random search, or have they learned to identify some clue at the surface of the sand?