Thanks to all who replied. I received four votes for the black-bellied plover and one vote for a tern or small gull. ? I am amazed that anyone could come up with an ID from my photos, which were distant grab shots taken in poor light.

The photos are post #202 on page 21 of this thread if anyone wants another look:http://www.pnwphotos.com/forum/showthread.php?14796-Wildlife-of-Edmonds-WA-2017/page21

Bill Anderson; Edmonds, WA. USA