A medium-sized (14 inches) tern, the Gull-billed Tern in summer is most easily identified by its pale wings, solid black cap, and thick black bill. In winter, this species loses most of its black cap, becoming light gray on the head with black eye-stripes. Male and female Gull-billed Terns are similar to one another in all seasons. The Gull-billed Tern inhabits every continent except Antarctica. In North America, this species breeds along the Atlantic coast of the U.S. south of New York, along the Gulf coast, and in southern California. Populations breeding in the Gulf are non-migratory, while those on the Atlantic and Pacific coasts winter in Florida, on the Gulf coast, and in the tropics as far south as Argentina. Gull-billed Terns primarily breed in dunes, on sandy barrier islands, or in coastal marshes. Similar habitats are utilized during the winter, although this species may also be found further inland in flooded fields at that time of year. Gull-billed Terns primarily eat small aquatic animals, including insects, small fish, and crustaceans. Gull-billed Terns may be observed flying above beaches and near-shore waters while catching prey. This species catches insects in the air, but does not dive into the water to catch fish (unlike many other terns), preferring to skim the surface or catch fish while standing in shallow water. Gull-billed Terns are primarily active during the day.