Sanderling

Like the willet, the sanderling is a member of the sandpiper family, but much smaller. In the picture below, a group of sanderlings run along the beach and a portion of a much larger willet is in the background to the right. When Wikipedia says they "rush madly around at the edge of the surf" it describes their activity perfectly, except "in unison" should be added to the description. They are like lemmings with ADD. What they are doing is feeding on small crustaceans, isopods and mole crabs, that live in burrows beneath the sand. As the tide comes in, these crustaceans move to the upper layers of the sand to feed on plankton and detritus that washes over them with each wave and then burrow back down again, very quickly, as the wave retreats. As the wave water swirls around it makes the sand softer and allows the sanderling beak to penetrate the sand further. So what the sanderling does is thrust its beak in the sand at random and to find these crustacean morsels. So the sanderling activity is maximizing their chances of eating their favorite food. The sanderling breeds in the High Arctic in the summer then migrates huge distances, 1,900 to 6,200 miles, for the winter. Their non-breeding plummage is pale, mostly white with a dark shoulder patch, and black legs and bill.  

Sanderlings rush about with a much larger willet behind them to the back right.

 

Two by two, as if into the Ark.