136 



LONG- WINGED SWIMMERS — LONGIPENNES. 



fuliginous-slate, the reniiges darker, nearly black terminally. Young, liyht phase : Head and neck 

 streaked with dusky brown and fulvous-buff, the latter usually predominating ; lower parts more 

 or less distinctly barred, or spotted transversely, with the same. Upper parts brownish dusky, 

 all the leathers bordered terminally with fulvous-buff. Young, dark phase: Prevailing color dark 

 brownish slate, the wings and tail darker. IMiddle of the neck, all round, indistinctly streaked 

 with grayish white ; lower parts, except jugulum and upper part of breast, barred with grayish 

 white, the bars broad and sharply defined on the crissum. Scapulars, interscapulars, wing-coverts, 

 upi^er tail-coverts, and feathers of the rump narrowly tipped with pale dull buff". " Bill light blue, 

 dusky at the end ; iris brown ; tarsi and basal ])ortion of the toes and webs light blue, the rest 

 black" (Audubon). Downy young: Entirely silky grayish brown, lighter on the under surface. 



A dull, Ugh 1 2)hase. 



Total length, about 18.50 inches ; extent, 40.00; wing, 11.80-13.15 (average, 12.67); middle 

 tail-feathers, 7.70-10.25 (8.66), the lateral rectrices, 4.90-6.25 (5,40) ; culmen, 1.15-1.40 (1.27) ; 

 tarsus, 1.50-1.85 (1.70) ; middle toe, 1.20-1.45 (1.34).i 



This species is almost if not quite as ^'ariable in plumage as the S. pomarinus, there being so 

 much individual variation in this respect that we have described oidy the light and dark extremes 

 of coloration. 



As may Ije found noted under the head of that species, specimens occur which in every character 

 of plumage, including length of tlie middle rectrices, are intermediate between the present bird and 

 /S. longicaudus. But there are two excellent characters, to which our attention has been directed 

 by Dr. L. Stejneger, which may always be relied on. These consist (1) in the color of the tarsi, 

 which in adult 2')arasiticus are always black, but in longicaudus light bluish (or, in dried skins, 

 more or less olivaceous) ; and (2) in the different proportions of the bill, parasiticus having the 

 nasal shield much longer, measured along the culmen, than the distance from the anterior border 

 of the nostiil to the tip of the bill, these measurements being ec|ual in longicaudus. 



The Parasitic Jaeger is a northern species, althougli not as exclnsively boreal as 

 are the ponun^ inns and the longicaudus. It is common both to Arctic An\erica and to 

 the more northern portions of Asia and of Europe. Messrs. Evans and Sturge 

 mention meeting with it on Spitzbergen. They saw it tormenting — as is its manner 

 — almost every flock of Kittiwake Gulls and Terns, but they met with neither its 

 nest, nor its eggs or young. Pennant narrates that the Arctic Skua — as he calls 

 this species — Avas breeding, at his time, on the islands of Islay, Jnra, and Rona ; 

 and Mr. A. G. IMore (" Ibis," 1865) thinks it highly probable that a few pairs still 

 linger in some of the numerous islands of the Hebrides. It is said to be extinct 

 at Jura. 



Thompson, in his "Birds of Ireland," states that a pair was shot in 1837 on 

 the Island of Kona. He further states that they still breed in Sutherland and in 



1 Extreme and average nieasnreiueuts of twenty-two adults. 



