33 NORTH AMERICAN BIRDS. 



Upper purls rustj- yellow, spotted with black ; lower parts whitish gray. 

 Length 13.00-14.00, wiug 10.10-11.15, tail 4.50-5.00 (forked for about .00- 

 1.00), culnien 1.00, tarsus 1.25, middle toe, with claw, about 1.25. Eijgs 2-5, 

 1.78 X 1-2C, ovate, or short-ovate, deep olive (varying in intensity, however), 

 rather indisliuctlj' spotted or blotched with brown. Mab. Arctic regions ; 

 in North America south, in winter, to New York, the Great Lakes, and 

 Great Salt Lake (casually to Bermudas and Peru). 



62. X. sabinii (Sab.). Sabine's Gull. 



rt'. Culmen nearly as long as tarsus ; tail forked for at least one and a half times 

 the length of the tai'sus; wing about 16.00; legs and feet red. (Subgenus 



(3.) Creagrus Bonap.). Summer adult : Head and upper part of neck sooty slate, 

 with a whitish patch at base of bill; mantle pearl-gray, the wing-coverts 

 and outer webs of scapulars whitish ; quills black, the shorter ones tipped 

 with white; rest of plumage white; bill black, with yellowish tip; legs and 

 feet bright red. Young : Plumage generally, including head and neck, 

 white ; hind-neck, back, and scapulars, ashy brown, the tips of the feathers 

 margined with white ; tail-feathers (except outermost) with a black subtcr- 

 niinal spot ; a duskj' space immediately in front of eye, and another on car- 

 coverts. Length about 23.00, wing 16.00, tail 8.00 (forked for about 3.30), 

 culmen 1.85, tarsus 1.90, middle toe, with claw, 2.00. Hab. Pacific coast of 

 South America; accidental in California (Monterey? San Diego? San Fran- 

 cisco) — . X. furcata (Neb.). Swallow-tailed GuIL 



Gencs GELOCHELIDON Brehm. (Page 24, pi. IX., fig. 4.) 



Species. 



Summer adult .• Top of head and hind-neck deep black ; upper parts pale pearl- 

 gra}-, rest of plumage pure white; bill deep black, feet blackish. Wiiiter adult: 

 Simihxr, but head and neck white, the hind-neck tinged with grayish, the ear- 

 coverts and spot in front of eye darker grayish. Young : Similar to winter adult, 

 but upper parts washed with buflf or clay-color, the top of head, hind-neck, back, 

 and scapulars sometimes streaked with dusky. Downy young : Above light gray- 

 ish buff, with several largo and tolerably well defined dusky spots on hinder half 

 of head, a distinct dusky stripe down each side of hind-neck and upper back, the 

 wings, rump, and flanks with rather distinct largo spots of dusky ; lower parts 

 white, tinged with grayish on sides of throat; bill brownish, inclining to orange (in 

 life) on lower mandible ; feet dull brownish orange (in life). Length 13.00-15.25, 

 wing 11.75-12.25, tail 5.50 (forked for 1.50-1.75), culmen 1.40, depth of bill at base 

 .45. Nest along sea-beach, in sand or shingle. Eggs 1.84 X 1-33, ovate, light buffy, 

 varj'ing to pale olive-buffy, distinctly spotted and blotched with deep brown and 

 lavender-grayish. Hab. Nearly cosmopolitan ; in America, Atlantic side, froni 

 Brazil north to Long Island, casually to Massachusetts; vcrj- rare inland; both 

 coasts of southern Mexico and Central America in winter. 



63. G. nilotica (IIasselq). GuII-billed Tern. 



