Guide to North American Birds
Conservation status Evidently far less numerous on the Atlantic Coast today than it was historically. Human disturbance and loss of nesting sites among likely causes. Has begun nesting on rooftops in some Gulf Coast areas. Colonized southern California, apparently from western Mexico, beginning to nest at Salton Sea in 1920s and at San Diego in 1980s.
Family Gulls and Terns
Habitat Salt marshes, fields, coastal bays. Restricted to seacoast in North America (except in Florida and at Salton Sea, California), but does most foraging over marshes, pastures, farmland, and other open country just inland from coast. Nests mostly on beaches, islands. Reportedly used to nest more often in salt marshes, abandoned those sites because of human persecution.
Besides the thick bill that gives it its name, this tern has a relatively stocky build and broad wings. Typically seen in leisurely flight over marshes, hawking for insects in the air or swooping down to take prey from the water or the ground; unlike typical terns, rarely dives into water for fish. On the ground, walks better than most terns. Widespread in warmer parts of the world, but local in North America, mainly in southeast. Generally found only in small numbers.

Photo Gallery

Feeding Behavior

Forages by flying slowly into wind, dipping to surface of land or water to pick up items, or by catching flying insects in the air. Sometimes forages while walking on ground; rarely plunges into water.


Eggs

2-3, sometimes 1-4. Pale buff, spotted with dark brown. Incubation is by both parents (although female may do more), 22-23 days. Young: Leave nest a few days after hatching, move to dense plant cover if nearby. Both parents bring food for young. Age at first flight 4-5 weeks. Young may remain with parents 3 months or more, beginning southward migration with them.


Young

Leave nest a few days after hatching, move to dense plant cover if nearby. Both parents bring food for young. Age at first flight 4-5 weeks. Young may remain with parents 3 months or more, beginning southward migration with them.

Diet

Mostly insects. Feeds on a wide variety of insects, caught on ground, in air, or at surface of water; also spiders, crabs, shrimp, mollusks, earthworms, marine worms, small fish, lizards, frogs, toads, rodents, small birds.


Nesting

Colonial breeder. Colonies usually small, not as densely packed as those of many terns. Has some aerial displays, but much of courtship display takes place on ground, involving elaborate posturing, bill-pointing, male feeding female. Nest site is on open ground, sometimes on gravel roof. Nest (built by both sexes) is shallow depression, often with rim of soil, addition of some plant material and debris.

Illustration © David Allen Sibley.
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Text © Kenn Kaufman, adapted from
Lives of North American Birds

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Migration

Mainly a summer resident in California and on Atlantic Coast; some remain through winter on Gulf Coast.

  • All Seasons - Common
  • All Seasons - Uncommon
  • Breeding - Common
  • Breeding - Uncommon
  • Winter - Common
  • Winter - Uncommon
  • Migration - Common
  • Migration - Uncommon

See a fully interactive migration map for this species on the Bird Migration Explorer.

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Songs and Calls

Rasping katy-did, similar to sound made by that insect.
Audio © Lang Elliott, Bob McGuire, Kevin Colver, Martyn Stewart and others.
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How Climate Change Will Reshape the Range of the Gull-billed Tern

Audubon’s scientists have used 140 million bird observations and sophisticated climate models to project how climate change will affect this bird’s range in the future.

Zoom in to see how this species’s current range will shift, expand, and contract under increased global temperatures.

Climate Threats Near You
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Climate threats facing the Gull-billed Tern

Choose a temperature scenario below to see which threats will affect this species as warming increases. The same climate change-driven threats that put birds at risk will affect other wildlife and people, too.