NATATORES — LARIOE — LARUS. 313 



THE KITTIWAKE, OR THREE-TOED GULL. 



Larus tridactylus. 



Larus tridactylus, Lin. Bonaparte, Ann. Lye. N. Y. Vol. 2, p. 359. Richardson, F. B. A. Vol. 2, p. 423. 



Audubon, B. of A. Vol. 7, p. 146, pi. 444. 

 Rissa id. Leach. Bonaparte, Geog. and Comp. List, p. 62. Giraud, Birds of Long island, p. 361. 



Characteristics. Hind toe obsolete, and without nail. Mantle blue-grey. Quills mostly 

 black at the point. Summer adult : head and neck pure white ; bill 

 yellow. Young, varied with greyish ; bill black. Tail with a black 

 subterminal band. Length, 17-0. 



Description. Bill moderate, robust, decurved above, 1*5 long measured from above. 

 Tibia bare beneath. A mere rudimentary knob occupies the place of the hind toe. First 

 quill longest. Tail even, longer than the wings. Summer: Mantle bluish grey ; bill greenish 

 yellow ; eyelids red ; feet black ; head, neck, rump, tail and all beneath pure white. Winter 

 and young, darker above ; the head and neck grey, with minute dark streaks, and darkish 

 before the eyes and auriculars. In the young, the bill is black. 



Length, 16-0-18-0. 



This species is more abundant on the shores of Rhode-Island and Massachusetts than on 

 this coast. It is a northern species, breeding from Maine towards the arctic circle. Eggs 

 light olive-green, with numerous irregular spots of dark brown. It rarely occurs south of 

 New- York. Common to both sides of the Atlantic. 



(EXTRA-LIM1TAL ) 



L. eburneus. (Aud. B. of A. Vol. 7, p. 150, pi. 445.) Pure white; bill yellow; feet black. Tarsus 



1*6. Young: head and wings faintly streaked with brown; tips of the quills and tail dusky. 



Length, 19 f 0. Newfoundland northwardly. 

 L. leucopterus, Bonap. (Aud. B. of A. Vol. 7, p. 159, pi. 447.) Back, wings and upper surface of 



the quills bluish grey ; all the remainder of the plumage pure white. Bill yellow-orange on the 



angle beneath. Young: bill yellow, tipped with black; brown streaks on the head, and short 



bars of the same on the back, wings and tail. Length, 26 "0. From New-York northwardly. 

 L. occidentalis. (Aud. lb. Vol.7, p. 161.) Bill yellow. Back and wings greyish blue. Head, 



tail and all beneath white. Ends of the quills white ; the remainder parts of the quills greyish black. 



Tarsus 3-0. Young, mottled with brown and greyish brown. Length, 27-0. Allied to argen- 



talus. Northwest coast of America. 

 L. glaucus, Brunn. (Aud. lb. Vol. 7, p. 170, pi. 449.) Mantle, wings and tail greyish blue. Head 



and all beneath white. Bill yellow : feet flesh-colored. Tarsus 3 -0. Young : bill black at tip. 



Color yellowish brown, spotted and barred above with dusky brown. Length, 30-0. Labrador 



northwardly. 

 L. franklinii. (Richardson, F. B. A. Vol. 2, p. 424.) Bill and feet vermilion. Mantle pearl-grey. 



Five outer quills broadly barred with black ; the first tipped with an inch of white. Hood black. 



All beneath white, tinged with rose-color. Length, 17*0. 



[Fauna — Part 2.] 40 



