Murmuration
While explaining mole crabs to a man who worried he might be "stepping on baby sea turtles in the sand," I saw small shorebirds murmurating over the surf--one of my favorite sights in seven months at Cannon Beach. Murmuration is also one of my all-time favorite words.
Murmuration usually refers to a flock of starlings, but sometimes it's used to describe the tight, twisting formations of other birds that stay so close together they seem to move as a single organism. The sanderlings I saw swooped and veered in perfect unison, many individuals moving as one.
Here's a video with a nice example of dunlin murmuration.
The word murmuration also refers to "the act of murmuring: the utterance of low continuous sounds." This leads my meandering mind from shorebirds to seabirds--from sanderlings to common murres. The name murre refers to this seabird's call, which I heard this morning as a distant murmuration above the surf while watching a murmuration of sanderlings.