It resembles the common tern. Its back and upper wings are a light pearly-grey, while its underparts are white. The tip of the white tail extends well beyond its wing tips when the bird is at rest. In the summer it has a black cap, nape and bill. The flight of this bird is distinctive, with rapid, shallow wingbeats of equal emphasis on the upstroke and downstroke.
Roseate terns feed primarily on American sand lance, a small marine fish.
Roseate terns arrive on the breeding grounds in late April or early May and begin nesting one month later. In New York, roseate terns are always found nesting with common terns. The nest may be only a depression in sand, shell or gravel, and may be lined with bits of grass and other debris. It is usually placed in dense grass clumps, or even under boulders or rip-rap. Both adults incubate the eggs for about 23 days, and the young fledge in 22- 29 days.