アメリカコアジサシ Sternula antillarum

Tiny tern with quick flicking wingbeats. A real beach bum, rarely straying far from sand, both on the coast and along inland rivers and lakes. Breeding adults have yellow bill, stumpy yellow feet, white forehead, and black cap. Nonbreeding and immatures have a black bill, blackish nape, and dark shoulder bar, but still always identifiable by size and quick wingbeats. Often seen with other terns. Listen for shrill high-pitched calls.