These are Least Sandpipers, one of the small Sandpiper species that are generally grouped together as "peeps". They are about the length of a common House Sparrow, a tad lighter in weight, though with much longer wings. We generally see them in small flocks, feeding as they scurry along mud flats or sandy shorelines. They are usually hard to get close to, just when you are almost close enough to really look at them, they fly up the shore another fifty feet, always staying just out of reach. I suppose they must sit and rest sometime, but in general they are birds in perpetual motion, either on the ground or in the air.
I shot a set of pictures of them flying three days ago and now finally looking through the pictures I appreciate the peeps even more. They are great in the air, turning together like schooling fish, changing the group color from light to dark to light again as they wheel above the water. They fly so fast I never really noticed, they are so coordinated that most of them even have their wing beats synchronized, beating their knife wings up and down in unison as they cut their flock through the air. Amazing.
What do I do with a handful of photos, none great, but all fun? Post'em all I guess. Enjoy.