Tom O wrote:
Ed,
Greta pictures and thanks for the EXIF.
One of the things that is confusing about a lot of birds is that
they change into their seasonal plumage so soon.
These Forester's Terns seem to be in Winter Plumage per my guide book.
Since they are immature as you say, they really make it interesting trying to ID.
Tom
The cinnamon color on the back is the key for the Juvenile. It wears off pretty fast and then they look very similar to the non-breeding adults.