Or let me lump them all together and call them shorebirds! After a couple of hours on the beach I learned two things - they do not stand still, but they do come amazingly close if you just lay down in the sand and hold still.
The birds were in constant motion - hopping or running around, swirling the water, pecking at the shells - until they flew out to the rocks. As soon as something moved, be it dog or photographer, they took off in a low flying cloud. Twisting, banking and finally landing on the rocky jetty. Wait a few minutes and the the cloud flew back. They have to pick through all those shells before the tide comes back in!