In addition to the usual tern diet of fish and crustaceans, the Gull-billed Tern catches insects in flight and on the ground. Although not numerous, it is widespread and breeds in scattered colonies.
General: Sexes similar. 13 to 15 inches in length.
Adult Alternate: White face, neck, breast, and belly. Black cap. Pale gray back and upperwings. Pale underwings. Thick, stout black bill. Black legs. Shallow forked tail.
Adult Basic: Similar to adult alternate, except it has a white forehead, dark streaking around the back of the head, and a variable dark ear spot.
Juvenile: Similar to adult basic, except the upperwings and back have brownish spots.
Coastal marshes and sandy beaches.
2-3 buff eggs with brownish spots. The eggs have a 22-23 day incubation period. Fledging occurs in 28-35 days. The nest is typically a shell lined depression in sandy ground in a salt marsh. Occasionally they build a nest that is a well-made cup of dead marsh grasses. Nests in colonies and often breeds with other species of terns.
- Tijuana river mouth, Imperial Beach