NATATORES — LAR1D.E - LARUS. 
313 
THE KITTIWAKE, OR THREE-TOED GULL. 
Larus tridactylus. 
Larus tridactylus , Lin. Bonaparte, Ann. Lyc. 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-LIMITAL) 
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, 19'0. Newfoundland northwardly. 
L. leucopterus, Bonap. (Aud. B. of A. Vol. 7, p. 159, pi. 447.) Back, ivings 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. Ib. 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. Ib. 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 
