162 TERNS 



vations are given in the Ibis as above. (See also a review of his paper 

 in The Auk, 1906, p. 348.) 



62. Xema sabini (Sab.). SABINE'S GULL. Ads. in summer. Whole 

 head and throat slate-color, bordsered posteriorly by black, back and sides of 

 neck, underparts, except throat, and slightly forked tail pure white; back 

 and wings dark pearl-gray; secondaries tipped with white; first primary 

 black, inner half of inner web, except at end, white; second to fourth pri- 

 maries similar, but tipped with white ; bill black, end yellow. Ads. in winter. 

 "Similar to the summer plumage, but the head and neck white, except 

 occiput, nape, and auricular region, which are dull, dusky plumbeous" 

 (B., B., and R.). Im. Forehead and lores white, rest of upperparts ashy 

 brown, feathers slightly tipped with whitish; tail white, broadly tipped with 

 blackish; underparts white. L., 14'00; W., 10'50; T., 4'50; B., 95. 



Range. Arctic regions to S. Am. Breeds on the coast of Alaska from 

 Kuskokwim River to Norton Sound and in n. Mackenzie, n. Keewatin, 

 and n. Greenland, and on Arctic islands of Europe and Asia; in migration 

 on both coasts of U. S. and casual in the interior; winters in Peru. 



Long Island, A. V. two records; July; Oct. 



^Nest^oi grasses, etc., on the ground. Eggs, 2-5, deep olive (varying 

 in intensity, however), rather indistinctly spotted or blotched with brown, 

 178 x 1-26 (Ridgw.). Date, Hooker Bay, Alaska, July 1 (Thayer Coll.). 



This boreal species is of rare occurrence in the Northern United 

 States, there being but three records for Massachusetts and the same 

 number for New York. 



Subfamily Sternince. Terns. (Fig. 24.) 



The Terns number some fifty species, distributed throughout the 

 world, ten being found in North America. They are more southern 

 than the Gulls, only two species nesting north of Maine, in Eastern 

 North America. They are also more migratory, none wintering on our 

 coasts north of the Carolinas. 



Terns are littoral, not pelagic, and, although characteristic of our 

 sea-coasts, like the Gulls, several species nest in the interior, the Black 

 Tern breeding only on bodies of fresh water. Beautiful as pearls, 

 graceful and active as Swallows, Terns are a constant delight to the eye. 

 They capture their prey of small fish by darting toward it like a living 

 arrow, plunging recklessly into the water, and, in some cases, swim- 

 ming a few feet beneath the surface. When looking for food they usually 

 fly with the bill pointed downward, a habit which will aid in distin- 

 guishing them from the Gulls, whose bill is carried more nearly in a 

 line with the body. 



Terns nest in colonies on islands and when disturbed are much 

 bolder than most Gulls, hovering close overhead and swooping toward 

 one fearlessly. The young are born covered with down, mottled in 

 pattern like that of Gulls. This plumage is both countershaded and 

 obliteratively marked; further proof of its protective value being 

 furntehed by the birds themselves, which, in obedience to the warning 

 note of their parent, squat flat and become almost invisible so long as 

 they remain motionless. Like the young of Gulls, young Terns are de- 



