Mystery Bird: Caspian Tern, Sterna caspia

Well, it is obviously a tern.

I'm going to go for Common Tern (Sterna hirundo), citing the black-tipped, orange-red bill, faint black tint to wingtips, gray body with lighter underbelly and the distinctive mask. This bird doesn't have the silver-white primaries or the right mask shape of the Forster's Tern, and lacks the white forehead patch of a Least Tern (and feels too large, although there's no scale here).

Caspian?

I believe that's a Caspian Tern, based on the "dark red bill with dusky tip" and relatively large amount of "dark under primaries" (Sibley).

Can't see any bread, so it isn't a sandwich tern.

What a beautiful photo of a Caspian Tern! The very heavy red-orange bill and black cap are a give away. Grrlscientist, could you please contact me directly about publishing one of your articles in a newsletter for Nisqually National Wildlife Refuge? Thanks.

I'm going with the Caspian, also.

Beautiful photo of a Caspian Tern- Heavy bill and dark underside of primaries are giveaways.

Based on the dark red with dark tip bill (and thicker, heavier bill) as well as the black cap and dark under the primaries I'd say Caspian Tern.

I'm going with Caspian Tern--big, red tern bill.

One more vote for Caspian Tern. Dark under the primaries and dark red, dark-tipped bill are good clues to identification. So is the flight posture of the tern -- flying with the bill oriented downward as if it were to heavy for the head to hold in a horizontal position.