Sanderlings

Pick  a sandy beach with a gradual slope and walk along the waters edge for any length of time, chances are you will see small sandpipers running back and forth in sync with the waves.  Most often they are Sanderlings.  They are by far the most widespread of the shorebirds.  While other shore birds will feed in this area near them, these little peeps act like they own the territory.
An  interesting fact about Sanderlings is that when they are mature and its mating season...they migrate to their nesting grounds....in the High Arctic tundra.  Immature birds often won't make the trip to the far north, they will stay in the wintering grounds.  I guess they think why bother.
The birds pictured are in their non breeding or winter plumage.