Small shorebird here
At the base of the dam. Non breeding plumage. I did not get a sense of a one legged bird so assume the other leg is tucked up in warm feathers.
The Spotted Sandpiper (Actitis macularius syn. Actitis macularia) is a small shorebird, 18–20 cm long. Together with its sister species, the Common Sandpiper (A. hypoleucos) they make up the genus Actitis. They replace each other geographically; stray birds may settle down with breeders of the other species and hybridize.