The Pomarine Jaeger 



that is succulent and weak or unwary or killable comes amiss to this 

 blackamoor, especially at the time of year when his own young are 

 clamoring for food. That he is brave enough none can deny, and for a 

 man to attempt to rob his nest is a really risky piece of business. For- 

 tunately, such unsocial graces are self-destructive. Of McCormick's 

 Skua, a closely related species from the Antarctic, it is said that the race 

 would perish through the speedy extermination of their customary 

 victims, the penguins, except for the fratricidal strife which exists among 

 themselves. Not only do they rob each other of eggs and young, but 

 their own chicks, never more than two in number, fight each other to 

 the death in the cradle; or else, filled with bitter humors, go wandering 

 off to be gobbled up by hungry neighbors. 



No. 267 



Pomarine Jaeger 



A. O. U. No. 36. Stercorarius pomarinus (Temminck). 



Synonyms. — Pomatorhine Jaeger. Pomarine Skua. Gull-hunter. 



Description. — Adult, light phase: Top and sides of head, upperparts (except 

 back of neck), and crissum brownish slate or dusky; rest of head and neck and under- 

 parts white; the region of ear-coverts and around on hind-neck tinged with straw- 

 yellow; primaries extensively white on inner webs, their shafts straw-yellow; central 

 feathers of tail projecting three or four inches beyond most of the others, their breadth 

 sustained to their abruptly rounded tips, which are twisted so that the lower surfaces 

 of the two feathers are brought face to face. Bill horn-color, tipped with black; feet 

 and legs black. Adult, dark phase: Entirely brownish slate, except sides of head and 

 hind-neck often tinged with straw-yellow, as before. Young, light phase: Upperparts 

 brownish dusky, the feathers of the back sparingly tipped with whitish or pale cin- 

 namon-rufous; those of the rump and upper tail-coverts spotted and barred with the 

 same; head, neck, and underparts white, everywhere (very sparingly on belly) streaked 

 or barred with dusky and pale cinnamon. Young, dark phase: Entirely brownish 

 slate, the underparts more or less barred with whitish or dull buffy. In the young of 

 the year the central tail-feathers do not project beyond the others more than half an 

 inch or such a matter. The light and dark phases described above do not represent 

 actual dichromatism, such as exists in the case of the Screech Owl, but only extremes 

 of coloration within which every intermediate condition may be found. The common- 

 est form is one in which the chest is sparingly, and the sides of the breast, hind-neck, 

 and sides are heavily barred with dusky and buffy. Length 558.8 (22.00); wing 

 349-3 (13-75); tail 209.6 (8.25); bill 39.4 (1.55); tarsus 53.3 (2.10). 



Recognition Marks. — Large crow size (size of California Gull); uniform dusky, 

 or dusky-and-white coloration; central pair of tail-feathers elongated, not tapering, 

 apparently set at right angles to the other feathers; bill rather small for size, sharply 

 hooked, and provided with thin "cere." Predatory in habit; oftenest found harassing 

 other birds of same family. 



1355 



