Crabbing with the Whimbrels

I intended to photograph black oystercatchers at low tide. I had good luck doing that in the past, but today, the oyster catchers wanted nothing to do with me and fled to a faraway rock offshore. 

Fortunately, a flock of whimbrels that were roosting on a nearby rock started milling about and didn’t seem too concerned with my presence. Over the next two hours, the group educated me on how to catch a mole crab. 

Each bird studied the sand on the shoreline as a wave receded, looking for clues that a crab was beneath the surface. I assume that an outgoing wave leaves an indent where a crab had recently burrowed under the sand. Another possibility is that the birds can hear the crabs in the sand or feel the sand shifting near their feet.

Once the whimbrels believed they were “on the crab”, they stuck their bills into the beach and literally sucked up a column of sand and spit it out on the beach. If the column contained a small crab, the birds pounced on it immediately.

Click on any image below for an expanded view

However, the whimbrels appeared to have difficulties handling the crabs. There were multiple instances in which the crabs slipped out of the bills of the whimbrels. As a result, each bird required multiple attempts to ingest its catch.

I found this puzzling. Most birds are very adept at handling prey items, and I doubt evolution would allow such sloppy handling of crabs to exist for long. There must be a reason for that behavior. Here is an example of a whimbrel mishandling a crab:

Despite the troubles manipulating their prey, this group of whimbrels were very successful at hunting crabs. I would estimate that they caught a crab 20% of the time, and the entire process was thoroughly entertaining. I’ll return to observe this flock as I’ve been thinking about a project involving whimbrels.