The large (18 to 21 inches long) and striking royal tern is easily recognized by its size, white body, pale gray wings, crested black cap, and orange bill. The only bird it may be confused with is the even larger Caspian tern, but that bird has a blood-red bill and no visible crest. Royal terns are graceful fliers for their size. Slim, with long, pointed wings and a wingspan that reaches nearly 4 feet, they have delicate, deeply forked tails and are well designed for life on the wing.
They are noisy while feeding and foraging, issuing their loud keet-keet or kir-reet calls constantly, a habit that makes them very difficult to overlook. If there’s a royal tern in the vicinity, it usually gets noticed.
Royal terns are almost always associated with salt water, so inland records are rare. This species, unlike some other terns, is more likely to forage near the shore, usually over breaking waves and pounding surf, and in quiet inlets and bays. After breeding, royal terns may wander up the Atlantic coast and are sometimes found as far north as Cape Cod, Massachusetts.
Royal terns subsist primarily on small fish, four inches or less in length, which they seize by hovering in the air and then diving into the water below. Crabs are another favorite food, as are oysters. Sometimes royal terns will fly close to the sea’s surface, scouting for schools of small fish and then dipping their bills repeatedly into the water to secure their meal.
Royal terns are colonial nesters and usually opt for a sandy site on an offshore island, where hundreds or even thousands of pairs congregate in such close proximity that the nests are nearly touching. Each nest is merely a depression in the sand. Both parents incubate the single egg (there are occasionally two), which hatches at four to five weeks. When the young can move about on their own, two or three days after hatching, they join as many as 10,000 other tern youngsters in a sort of avian day-care center that ornithologists call a crèche. Families recognize each other by sound, and each chick is fed only by its own parents. The young royal terns do not achieve full independence until they are nearly eight months old.