The Caspian Tern is the world's largest tern at 21 in/53 cm in length and with a wingspan of 50 in/1.3 m. It is characterized by its large and very red bill, black forehead and cap, black legs and long. forked tail. It feeds by hovering over the water and darting down head-first into the water to catch fish.

In general, terns are similar to gulls but have longer, pointed beaks and forked tails.