Caspian Terns enforce boundary laws but the more lenient Royal Terns associate freely with this species and allow them to share the nesting grounds.
They are self sufficient, quite aggressive (for Terns) and under protection are slowly moving northward to haunts they formerly occupied on the Delaware and Jersey coasts.
When diving for food they frequently disappear entirely beneath the water and remain below longer than other Terns. Their larger size is not apparent in flight but yellow tip on bill and black feet are good identification marks.
From Virginia south along Atlantic and Gulf Coast.