280 AVES NATATORES. [LARUS. 



reaching to the end of the tail : primaries terminated by 

 a large white space ; the shafts entirely white : mantle (in 

 the adult) pale bluish ash. 



L. glaucus, Temm. Man. d'Orn. torn. n. p. 757. Sab. in Linn. 

 Trans, vol. xn. p. 543. Glaucous Gull, Bew. Brit. Birds, vol. n. 

 pp. 209, & 212. Selb. Illust. vol. n. p. 498. pi. 99. Iceland Gull, 

 Edmondst. in Wern. Mem. vol. iv. pp. 176, & 182. 



DIMENS. Entire length twenty-nine inches: length of the bill 

 (above) three inches, (from the gape) four inches ; of the tarsus three 

 inches ; of the tail ten inches ; of the wing nineteen inches : breadth, 

 wings extended, five feet two inches. Faun. Bor. Am. 



DESCRIPT. Similar to the last, but larger, with the bill more robust, 

 and the tarsus longer. (Adult in winter.) Head and neck white, 

 streaked and mottled with gray : back, scapulars, and wing-coverts, pale 

 bluish ash, not so dark as in the L. argentatus : primaries terminated by 

 a large white space, extending upwards more than two inches ; the shafts 

 entirely white : tips of the secondaries, tail, and all the under parts, also 

 pure white: bill very strong; wax-yellow ; the angular projection of the 

 lower mandible bright arterial blood-red : orbits red : irides yellow : legs 

 livid flesh-colour. (Summer plumage.) Head and neck pure white, with- 

 out the gray streaks : the rest as in winter. (Young of the year.) Whole 

 plumage mottled throughout with white, gray, and light brown, as in 

 the young of the L. marinus and L. argentatus, but the colours are 

 always paler than in those species, especially those of the quills, which 

 are brown instead of dusky, with the shafts entirely white : bill horn- 

 coloured at the base, the tip brownish black; the angular projection of 

 the lower mandible not so strongly denned as in the adult : legs flesh- 

 colour. From the young of the last species, they are only to be distin- 

 guished by their greater size. (Egg.) Stone-colour, spotted with ash- 

 gray, and two shades of red-brown : long. diam. two inches nine lines ; 

 trans, diam. one inch eleven lines. 



A regular winter visitant in the Shetland Islands, where it arrives 

 about the middle of Autumn. In the southern parts of Britain rare, and 

 only occasionally met with : such individuals generally young birds in 

 immature plumage. A bold and voracious species, preying on fish and 

 other birds, as well as on carrion. Retires to the Arctic Regions to 

 breed. 



GEN. 110. LESTRIS, Illig. 



303. L. Cataractes^ Temm. (Common Skua.) Central 

 tail-feathers but slightly elongated ; of equal breadth 

 throughout ; square at the extremities : tarsus two inches 

 eight lines. 



L. Cataractes, Temm. Man. d'Orn. torn. n. p. 792. Cataractes 

 vulgaris, Flem. in Edinb. Phil. Journ. vol. i. p. 99. Skua Gull, 

 Mont. Orn. Diet, fy Supp. Bew. Brit. Birds, vol. n. p. 229. 

 Common Skua, Selb. Illust. vol. n. p. 514. pi. 100. 



DIMENS. Entire length twenty-five inches; the same, central tail- 

 feathers excluded, twenty-two inches : length of the bill one inch nine 

 lines ; of the tarsus two inches eight lines. 



