When I first spotted this bird it was quite distant. It had a pale-winged appearance for a tern, seen even at a distance through a scope. It flew beyond a flock of jager-flushed Ring-billed Gulls, and kept on flying on it's own. In addition to the evenly-pale wing profile, the photos below show a very thin black trailing edge to the primaries. Tail was forked. Neck/head was very stout. Black cap showed clearly through a scope view. Flight was quite buoyant with each wingbeat. When bird was seen from lot 1, it was only seen by itself.