450 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I50 



Migrant from the north. Fairly common in the Gulf of Panama ; 

 one report from the Caribbean coast. 



The first record of this tern is found in 2 skins in the American 

 Museum of Natural History, an immature male and another male, 

 apparently adult in winter dress, taken by Rex Benson near Agua- 

 dulce, Code, September 24, 1927. In crossing from Balboa to 

 Isla San Jose on February 7, 1944, I observed several hundred feed- 

 ing over the sea from 50 to 15 kilometers off the island. Other 

 sight records are for occasional birds seen near Panama Viejo, where 

 Eisenmann (Wilson Bull., 1951, p. 182) reported one, considered 

 to be a nonbreeding, summering individual, on July 16, 1950, and 

 I have recorded others April 3 and December 18, 1955. With this 

 scanty information it was of considerable interest to me to find 

 gull-billed terns fairly common in January 1963 over the channels 

 and mud flats of the Bahia Parita area below Aguadulce, Code. 

 January 16 and 17 1 shot five from small groups coursing in a strong 

 wind at Gallo and on January 25 recorded 40 resting in a close 

 flock at low tide, on a sandspit on the shore of the bay. Two of those 

 taken had eaten shrimp, two others fiddler crabs, and the fifth a 

 small fish. As this is the general area where Benson secured his 

 specimens it appears that this tern may be regular here in occurrence. 



The record for the Atlantic side is of one seen by Eugene Eisen- 

 mann, August 28, 1958, near Coco Solo, Canal Zone. (I know 

 of no basis for the statement by Hellmayr and Conover, Cat. Birds, 

 Amer., pt. 1, no. 3, 1948, p. 299, that includes the Caribbean side 

 of Panama in the winter range.) The race aranea breeds along 

 the Atlantic coast from southeastern Maryland and Virginia to 

 eastern Florida, the Bahamas, and the Virgin Islands, and is found 

 in winter from the Gulf coast of the United States south along 

 Central America, to northern South America. 



The gull-billed tern as a species ranges throughout the world, ex- 

 cept in the colder regions and the islands of the central Pacific. While 

 all are closely similar in appearance, several races are recognized, 

 two of them in North America, viz, the one discussed above and 

 a western one, Gelochelidon nilotica vanrossemi Bancroft (described 

 in Trans. San Diego Soc. Nat. Hist., vol. 5, Dec. 10, 1929, p. 

 284; type locality Salton Sea, Imperial County, California). Its 

 known breeding grounds are on islands in Salton Sea and along 

 the coast of Sinaloa, with other records not wholly definite from 

 the head of the Gulf of California (Isla Monteague), and the 

 coast of Sonora (Bahia Tobari). This subspecies is separated from 

 G. n. aranea by slightly larger size, stronger, heavier bill, and slightly 



