Here's a first summer Common Tern, smaller than the Sandwich, with a dark carpal bar and heavy bill.
This second bird is the same age but has a less distinct carpal bar and a more extensive black cap. It never gave me good views, and when it flew it headed straight to the horizon. Still, the legs don't look overly short and the bill is about "middling" in length.
Here's an adult, which had some dark red on the bill and a gray blush on the breast.
