Could they be Baird's Sandpipers? I believe you're in their migration path.Here's a similar image I found that claims to be mostly Baird's.
Oops! Here's that link: http://jerryjourdan.blogspot.ca/2010/08/two-hour-birding-28-aug-2010.html
Thanks, but I sent it to Christian Artuso and he said they were Sanderlings. Thanks anyway!
I'd definitely take his advice over my guess :-) I've never seen Sanderlings, though with good fortune I may on Friday. Presumably these are in adult breeding plumage (the buff throats), but are the dark lines on the wing edges definitive?
I sent him some other pictures of them I took also, showing the over wing and them landing, so he identified them from those, he asked if I had any others when I first showed him this picture.
That would help. Just to say that we got good fortune yesterday, and saw 3 Sanderlings (immature) - as well as many, many more migrant shorebirds. Maybe BirdBoy will post some pictures.