138 BIRDS. PALMIPIDES. Cataractes. 



those which we have examined. It does not appear to be subject to much 

 variation of plumage with age or seasons. Some individuals have been found 

 having the chin and forehead tinged with ash-colour. — The common Skua is 

 gregarious during the breeding season. It lays two eggs of a muddy green 

 colour, marked with irregular brown spots, and* intermixed with smaller white 

 spots. — The nest is carelessly constructed of a few dried weeds, and is found 

 in unfrequented moors. It breeds in the Zetland islands, where I have ob- 

 served it, as in Foulah and Unst, and on Rona's Hill in Mainland. When 

 the purposes of incubation have been accomplished, it retires from its sum- 

 mer haunts, and leads a solitary life on the ocean. It is found in our seas at 

 all seasons. It is rare in the southern parts of the kingdom ; and even about 

 the Zetland islands it is by no means a common bird. 



222. C. parasiticus. Arctic Skua. — Plumage above black ; 



the two middle tail-feathers produced. 



Larus par., Linn. Syst. i. 22G. Penn. Brit. Zool. ii. 533 Lestris par., 



Temm. Orn. ii. 796" — E, Teazer, Dung-hunter, Dung-bird, Scull, Boat- 

 swain ; S, Faskidar, Badock, Allan, Scouti-allan, Dirten-allan ; N, Shui. 

 — Common on all parts of the coast. Breeds in the Hebrides and 

 Northern Isles. 



Length 21, breadth 43 inches ; weight 16 ounces. The bill is 2 inches in 

 length, of a greyish-black colour, darkest towards the point. The upper man- 

 dible is rounded along the margin towards the base, a little prominent in front 

 of the nostrils above, and bent downwards at the end. The under mandible is 

 bent inwards at the edges, and at the apex forms a groove sloping downwards ; 

 at the base it is grooved laterally ; and, at the junction of the two sides beneath, 

 there is an angular prominence. The eyes are surrounded with a narrow black 

 orbit, and the irides are of a hazel-brown colour. The legs are of a black co- 

 lour, rather slender. The claw of the outer toe is short ; that of the middle- 

 toe broad and grooved below ; and of the inner toe narrow and arched. The 

 tongue is fleshy and bluntly bifid. The middle of the palate, and a ridge on 

 each side, are covered with cartilaginous reflecting teeth. The trachea at the 

 division of the bronchia? is furnished with a small bony plate. Rectum with 

 too long broad vermiform appendages. Crown, nape, back, quills, tail and its 

 under covers, brownish-black, deepest on the head and extremities of the 

 wings and tail. Front, chin, cheeks below the eye, side of the neck, and be- 

 low white. An indistinct collar of wiry-feathers round the neck. The wings 

 reach beyond the lateral feathers of the tail ; the first quill the longest. Tail 

 of 12 feathers; the five exterior ones rounded, the extremity of the shaft pro- 

 jecting ; the two middle produced feathers taper to a point. Female similar. 

 — Nest in heath, of dry grass. Eggs 2, dark olive-green, with irregular 

 blotches of liver brown. The young have the head and hind neck grey, with 

 brown streaks ; the back dusky-brown, the feathers with pale edges ; below 

 blackish-grey, with a ferruginous tinge ; the base and tips of the quill and 

 tail-feathers whitish. In its young state, and as it approaches to maturity, it 

 is the (Larus crepidatus) Cepphus of Lyson, Phil. Trans, xlii. 137., and the 

 Black Toed-Gull of Pennant, Brit. Zool. ii. 532 The " Arctic Bird" of Ed- 

 wards, tab. 148., frequently referred to as belonging to this species, appears to 

 be distinct, as indicated by the bright yellow colour of the legs — Like the pre- 

 ceding species, the Arctic Skua is subgregarious only in the breeding season, 

 and remarkably bold in defending its nest. It has recourse to stratagem to 

 lead intruders from its eggs or young, tumbling over, as if dying, or feigning 

 a broken wing. It is worthy of remark, that this species breeds before it at- 

 tains the plumage of maturity. 



Gen. CI. LARUS. Gull.— Bill hooked; tail even.— The 

 Females are similar to the Males in plumage, but less in 



