FAMILY LARIDAE 455 



Apparently these terns may follow a breeding schedule that is 

 not based on a 12-month annual cycle, as on a trip on the launch 

 Sea Raider with Capt. Richard E. Parker, on February 25 and 26, 

 1957, that I made especially to look for them, no terns were found. 



Robert Cushman Murphy (Nat. Hist., 1938, p. 177) in September 

 1937 found numbers of bridled terns around Cabo Marzo and the 

 Octavia Rocks, on the Coast of Choco, a short distance south of 

 the Panamanian boundary. Robins (Condor, 1958, p. 302) re- 

 corded them in July 1957 from Punta Garachine to beyond Bahia 

 Pinas. And Dennis R. Paulson, on the yacht Argosy, saw a num- 

 ber south of Isia San Jose September 7, and others near Bahia Piiias, 

 September 12, 1961. 



It is probable that the race Sterna anaethetus recognita Mathews, 

 which has nested in Caribbean waters on islands off British Honduras, 

 and at a number of islands in the West Indies, will be found even- 

 tually on the northern shore of Panama. It differs from 5*. a. nelsoni 

 in having the under surface of the body pure white and, with the 

 wing ranging from 251 to 263 mm., averages slightly smaller. 



STERNA FUSCATA Linnaeus: Sooty Tern; Gaviotin de Dorso Negro 



Medium size ; black above, white below. 



Description. — Length, 340 to 390 mm. Adult, line from gape to 

 around eye and entire upper surface black; forehead, side of fore 

 crown back above eye, and undersurface white, tinged faintly with 

 gray on posterior area; outer rectrix white basally and on outer 

 web ; inner web black at tip. 



Immature, in first plumage, above, including side of neck, wings, 

 and tail sooty black ; wing coverts, back, rump, and tail tipped with 

 dull buff or white; under surface dusky gray; abdomen partly 

 white; flanks and under tail coverts tipped with dull cinnamon- 

 buff. 



Iris dark brown ; bill black ; tarsus and toes dusky black. 



This is a tern of worldwide range in tropical and subtropical seas 

 that is little known in Panama. Two races are recorded, one on 

 the Pacific side of the Isthmus and one on the Atlantic. 



STERNA FUSCATA FUSCATA Linnaeus 

 Sterna fuscata Linnaeus, Syst. Nat., ed. 12, vol. 1, 1766, p. 228. (Hispaniola.) 



Characters. — More distinctly white on the lower surface, with the 

 gray wash faint, and only on the abdomen and under tail coverts. 



