We saw these in North Carolina, all over the coast, cruising over the water, plunge-diving down into it to catch fish, and hanging out in big groups on pier posts, always managing to look like they were fighting a strong gale as they were just sitting there. They have deep reddish-orange bills, and that black cap only extends all across the forehead when they are in breeding mode, so says Sibley's.
I can't think of anything more enlightening to say about these birds. Just glad I got at least 2 outta the jar this month! :-)