Identificaciones de fcassidy

I do not know what bird this is. It ran off the Willet pictured. Seems to be a shore bird (?) was wading and pecking at the edge in the water.

It had a very, very yellow beak, which unfortunately doesn't show up well; it's not a long one like I'd expect to see in a shore bird.

There's a black patch that circles the beak then runs up the middle between the eyes to the top of the head; has greyish cheeks and a slightly speckled brown body. Underside possibly grey?

Any help would be appreciated!