GULL-BILLED TERN


Sterna nilotica


Description:

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.


Appearance:

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.


Habitat:

Coastal marshes and sandy beaches.


Nesting:

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.


Observed Locations:

  • Tijuana river mouth, Imperial Beach





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Adult Alternate

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Adult Alternate

 

 


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Copyright © Scott Streit, 2000.