748 SYSTEMATIC SYNOPSIS.— LQNGIPENNE 8— GAVI^. 



gins. Hallux rudimentary or not well developed, the ungual phalanx being generally obsolete 

 Pattern of primaries and livery of the young, peculiar. Nests on crags. 



Analysis qf Species. 



Feet dark; bill clouded with oliraceotiB, about 1.50 long ; wing 12.00. 



Hallux rudimentary, without a claw-bearing phalanx tridactyla 782 



Hallux better formed, bearing a claw Icotzehuii 783 



Feet coral red (drying yellow); bill clear yellow, about 1.20; wing 13,00 brevirostris 784 



783. R. tridactyla. (Lat. tris, thrice ; daciylus, digit.) Common Kittiwake. Hind toe only 

 appearing as a minute knob, its claw abortive. Adult, breeding plumage : BUI light yellow, 

 clouded with olivaceous. Head and neck all round, under parts and tail, pure white. Mantle 

 rather dark bluish or cinereous-blue, the tertiaries and secondaries of the same color nearly to 

 their tips, which are white. Primaries : the first very light bluish- white, without white apex, 

 its outer web, and its inner web for about two inches from the tip, black ; second like the first, 

 but without the black outer web, its tip being black for nearly the same distance as the first, 

 its apex with a minute white spot ; on the third and fourth the black tips grow shorter, while 

 the apices are more broadly white ; this lessening of the black on each feather is exactly pro- 

 portional to the shortening of the successive quills, bringing the bases of all the black tips in 

 the same straight line (a pattern peculiar to the species of Bissa). A sub-apical black spot is 

 usually present on one or both webs, but is sometimes absent. Legs and feet blackish. Iris 

 reddish-brovm ; eye-ring red. Adult in winter : Occiput, nape behind, and sides of the breast, 

 clouded with the color of the back, deepening into slate over the auriculars. A very small but 

 well-defined black crescent before the eye. Otherwise as in summer. Young : BUI black ; an 

 ante-ocular crescent, and a post-ocular spot, dusky-slate. A broad transverse bar across the neck 

 behind, the whole of the lesser and median wing-coverts, the bastard quiUs, the tertiaries, except 

 at their edges, and a terminal bar on the tail, black. The outer four primaries with their outer 

 webs, outer half of inner webs, and tips for some distance, black, the rest of the feathers pearly 

 white. Tips only of the fifth and sixth black, their extreme apices with a white speck. Length 

 lG.00-18.00; extent 36.00; wing 12.25; bUl above 1.40 to 1.50 ; along rictus 2.10; height 

 at base 0.50 ; at angle 0.40 ; tarsus 1.30 ; middle toe and claw 1.80. Arctic America and 

 Europe, chiefly coastwise, very abundant ; breeds from New England northward ; ranges in 

 whiter S. to the Middle States. Nests preferably not on the ground like most guUs, but on the 

 ledges of rocks and clifls overhanging the water, such as the guiUemots select ; nest of sea- 

 weeds, etc. Eggs like those of other guUs, 2.25 X 1.80. 



783, R. t. kotzebui'i. (To Otto von Kotzebue, the Eussian navigator.) Kotzebue's Kitti- 

 wake. It is a curious fact that the common kittiwake of the North Pacific usually has the 

 hind toe better formed — sometimes nearly if not quite as long as in ordinary guUs, with a 

 nearly or quite perfect, though small, claw. But I cannot predicate a specific character on this 

 score, since the development of the toe is by insensible degrees. (See Coues, Proc. Phila. 

 Acad., 1869, p. 207 (footnote) ; Birds N. W., 1874, p. 644.) N. Pacific coast, abundant. 



784. R. breviros'tris. (Lat. Iremrostris, short-biUed.) Short-billed Kittiwake. Eed- 

 legged Kittiwake. Adult, breeding plumage : BUI very short, stout, wide at the base, the 

 upper mandible much curved, though not attenuated nor very acute. Convexity of culmen 

 very great toward the tip ; the culmen being, from the nostrils to the apex, almost the arc of a 

 circle, whose centre is the symphyseal eminence. Outline of rami of under mandible and gonys 

 both somewhat concave ; the eminentia symphysis but slightly developed. Tarsus very short, 

 hardly more than two-thirds the middle toe and claw. Wings exceedingly long, reaching, 

 when folded, far beyond the taU. Tail of moderate length, even. Bill a uniform clear light 

 straw- yeUow, with little or no tinge of olivaceous; iris hazel ; eye-ring red. Head and neck 

 all round, under parts and tail, pure white. Mantle deep leaden 6r bluish-gray, much darker 

 than in It. tridactyla ; the color on the wings extending to within half an inch of the apices of 



