The Baird's Sandpiper, the shorebird on the right in these photos, was on a grassy islet with Short-billed Dowitchers and Greater Yellowlegs. The sharply demarked chest striping with a tinge of yellow marks this shorebirds field marks. It is not rare, usually uncommon, but can be hard to find especially in large flocks of peeps.
Baird's Sandpiper
Baird's Sandpiper 100
Baird's Sandpiper 101
Baird's Sandpiper 102