Correct me if I'm wrong but the bird appears to actually be a nonbreeding Black Tern. This would appear to be the first ever entry for the species in the eBird database for Armstrong County. This is the same mudflat where I had and initially misIDed the Baird's Sandpiper a couple weeks ago. Which by the way, thanks to those on the list that very promptly gave me a confirmation on the Baird's ID.
Gibsonia, Allegheny County