JAEGERS AND SKUAS 151 



but with the upperparts darker, nearly black. Ads. dark phase and 1m. 

 Similar in color to corresponding stages of S. parasiticus. L., 22*00; W., 

 13-50; T., Ad., 8'00; Im., 5'40; Tar., 2'00; B., 1'55. 



Remarks. This species is to be distinguished from the two following by 

 its larger size and the rounded ends of its central tail-feathers. 



Range. N. part of N. Hemisphere. Breeds from Melville Island and 

 cen. Greenland s. to n. Alaska, n. Mackenzie, Melville Peninsula, and Baffin 

 Land, and also on Arctic islands of E. Hemisphere; winters off Atlantic 

 coast, s. to N. J.; common fall migrant on coast of Calif.; winters s. to 

 Galapagos, Peru, Africa, and Australia; accidental in Nebr. 



"Long Island, regular from June 15-Oct. 30 (Butcher). Ossining, A. V. 

 N. Ohio, casual on Lake Erie. 



Nest, on the ground. Eggs, 2-3, deep olive-drab sparingly spotted 

 with slate color, and light and dark raw-umber markings and black dots, 

 chiefly at the larger end, where confluent, 2'25 x 1*70 (Brewer). Date, 

 Cape Lisburne, Alaska, June 10. 



37. Stercorarius parasiticus (Linn.). PARASITIC JAEGER (Fig. 23a). 

 Ads. light phase. Back, wings and tail slaty fuscous; top of head and lores 

 nearly Mack; sides of head and back of neck straw-yellow, this color some- 

 times spreading down sides of neck and on throat; breast and belly white; 

 sides of breast, flanks, lower belly, and crissum slaty fuscous; tarsi and feet 

 (in dried specimens) black; middle tail-feathers pointed and extending 

 about 3 '00 beyond the others. Ads., dark phase. Entire plumage dark, slaty 

 brown, darker on top of head; underparts slightly lighter; sometimes 

 a trace of straw-yellow on sides and back of neck; tarsi, feet and tail as in 

 preceding. Im., light phase. Upperparts, wings and tail fuscous; feathers of 

 back, neck and head more or less bordered, tipped or barred with buffy; 

 hindneck and head sometimes buffy, streaked or barred with fuscous, and 

 varying from this color to plain fuscous; longer, lateral upper tail-coverts 

 barred with buffy; tail buffy, whitish at base; urfler wing-coverts barred 

 with buffy; underparts white, washed with buffy, and irregularly barred 

 with sooty fuscous; these bars sometimes very numerous when the under- 

 parts look as if washed with sooty fuscous ; again, they may be less numerous 

 and confined to breast and sides, leaving the belly white; central tail-feathers 

 pointed, projecting more or less beyond rest. Im., dark phase. Sooty fus- 

 cous feathers, particularly on underparts, more or less marked 'with ochrace- 

 ous-buff. L., 17-00; W., 13'00; T., Ad., 8'60; Im., 6'40; B., 1'15. 



Remarks. This species closely resembles S. longicaudus. Adults of both 

 species, whether in the dark or light phase of plumage, may always be dis- 

 tinguished from each other by the difference in the length of their central 

 tail-feathers, in addition to the characters given in the key. Young birds 

 can not be distinguished by color, but may be identified by the differences in 

 relative proportions of the bill. Eaton calls attention to the fact that in 

 parasiticus the shafts of all the primaries are white, while in longicaudus 

 only the outer two or three are white, the rest being abruptly brownish. 



Range. N. part of N. Hemisphere. Breeds from nw. Alaska, Melville 

 Island, and n. Greenland s. to Aleutian Islands, cen. Mackenzie (Great 

 Slave Lake), and cen. Keewatin, and on Arctic islands of Siberia and of n. 

 Europe s. to Scotland; winters from the Aleutian Islands s. to Calif., from 

 New England coast s. to Brazil, in Australia, and from coast of Europe s. 

 to Cape of Good Hope; casual in interior to the Great Lakes, Mo., Kans. and 

 Colo. 



Long Island, regular, Apl. 30; Aug. 6-Nov. 9. N. Ohio, casual on Lake 

 Erie. 



Nest, on the moors or tundras, a slight depression in the ground scantily 

 lined with grasses, etc., or on rocks by the sea. Eggs, 2-4, light olive-brown, 

 with frequently a strong greenish tinge and chocolate markings, more 

 numerous and sometimes confluent at the larger end, 2'25 x 1'65. Date, 

 Iceland, May 23; Bering Island, Kamchatka, May 29. 



