This bird looked different than the nearby White-rumped Sandpipers. It was the right size and shape and the wings extended beyond the tail, but this bird had less of a hooded look and it had a more extensive bib that contrasted with its belly. It was also behaving differently. It would stop and go as it was feeding, somewhat like a plover. When if flew, we noticed it did not have a white rump, so we thought it might be a Baird's. But, the bill is slightly curved with a little red at the base like a White-rumped, and it shows a little rufous in its scaps. It also has mustard-colored legs.
I'm not 100% sure that these flight shots are of the same bird as above, because a few birds took off at the same time, but we did get a good look at it in flight and it did not have a white rump.