FAMILY STERCORARIIDAE 437 



Dark phase, sooty gray above, blacker on crown, wings, and tail ; 

 brownish gray on lower surface. 



Immature, in light phase, head and neck streaked, and lower sur- 

 face more or less barred and spotted, with dusky brown. In dark 

 phase, underparts barred with grayish white. 



Adult, tarsi and feet black. Immature, tarsi bluish gray, with ends 

 of toes and webs black. 



Measurements (from Ridgway, I.e., p. 688). — Males, wing 301-340 

 (320), tail 164.5-235 (188.9), culmen 28-35 (31.2), tarsus 39.5-45.5 

 (41.9) mm. 



Females, wing 317-341 (323.7), tail 176-226 (199.7), culmen 29- 

 34.5 (31.8), tarsus 39-45 (42.1) mm. 



Visitor from the north. Known from one taken on the coast of 

 the Comarca de San Bias, and a few sight records. 



A male in the Herbert Brandt Collection at the University of 

 Cincinnati was collected by Wedel on November 27, 1934, at Puerto 

 Obaldia, San Bias. One was seen by Robert Cushman Murphy near 

 Isla San Jose, February 21, 1941 (see Wetmore, Smithsonian Misc. 

 Coll., vol. 106, no. 1, 1946, p. 34). Another was recorded in Colon 

 harbor Feb. 9, 1927, by Griscom (Amer. Mus. Nov. no. 282, 1927, 

 p. 3). 



STERCORARIUS LONGICAUDUS Vieillot: Long-Tailed Jaeger; 

 Salteador Rabudo 



Stercorarius longicaudus Vieillot, Nouv. Diet. Hist. Nat., nouv. ed., vol. 32, 

 Sept. 1819, p. 157. (Northern Europe.) 



Adult with central tail feathers projecting 80 to 150 mm. or more. 



Description. — Bill smaller; horny cere (supranasal saddle) shorter, 

 not more than length of distal segment of bill (dertrum). Length 

 adult 520 to 570 mm., immature 410 to 460 mm. Adult, crown, in- 

 cluding loral and orbital regions sooty black ; rest of head and hind- 

 neck yellowish white ; rest of upper parts brownish gray ; wings and 

 tail dull black; abdomen, flanks and under tail coverts gray; rest of 

 undersurface white. 



Immature, undersurface and upper tail coverts barred more or less 

 extensively with brownish gray. 



A few birds in dark phase have been reported in life, but this color 

 stage, if correctly identified, must be rare, as no specimens of it have 

 been collected. 



Tarsus light bluish gray, toes and webs black; immature, only 

 distal end of toes black. 



