Elegant Terns typically breed primarily on Isla Rasa in the Sea of Cortes, and disperse afterwards, though this may be changing due to changes in the fish population in the upper gulf.
While visiting Estero Beach in August of this year, there was a flock of perhaps one or two thousand Elegant Terns. I don't know if they bred there earlier in the year.
I did observe at least one pair exhibiting courtship behavior. I don't know if this pair was very early (for next year!) or very late (for this year).
Here is part of the flock lifting off:
(tap or click to enlarge)