Family Laride
GULLS AND TERNS.
This family contains about one hundred species divided equally between the subfamily Larinæ (Gulls) and subfamily Sterninæ (Terns). They are distributed throughout the world. Some forty species inhabit North America. With few exceptions they agree in possessing the marked characters of their respective subfamilies, under which they may be more conveniently treated.
Subfamily Larinæ. Gulls.
Generally speaking, Gulls are maritime and pelagic, though some species are found inland. As compared with Terns, Gulls are less graceful and active on the wing. In flight the bill points forward in the plane of the body, not downward toward the earth, as in the Terns. They procure their food largely by picking it from the surface of the water or land with their strongly hooked bills, not by plunging or darting, as do the Terns. Some of the species are true birds of prey, and feed on small mammals and the eggs and young of other birds. Gulls are better swimmers than Terns, and pass much time resting on the water. They nest in colonies, generally on the ground, sometimes on rocky ledges, and rarely in trees.
I. Wing over 15.00.
KEY TO THE SPECIES.
A. Back dark slaty black.
B. Back pearl-gray. a. Outer primaries marked with black. b. No black on primaries. 61. Bill under 2.00. 47. BLACK-BACKED GULL. 51a. AM. HERRING GULL. 51. HERRING GULL. 62. Primaries light pearl-gray, fading gradually into white at their 43. ICELAND GULL. tips GULLS. 63. Primaries pearl-gray, tipped with white, and with well-defined gray spaces on the outer webs of the two outer primaries and on both webs of the third and fourth primaries. c1. Bill over 2.00 45. KUMLIEN'S GULL. 42. GLAUCOUS GULL.
C. Back grayish, whitish, or brownish, or mottled or spotted with grayish or brownish. a. Tail black or blackish, with or without irregular white markings. a¹. Wing over 17.50; depth of bill at nostril over 70. 47. BLACK-BACKED GULL (Im.). a2. Wing under 17.50; depth of bill at nostril under 70. 51a. AM. HERRING GULL (Im.). 51. HERRING GULL (Im.). 6. Tail white or whitish or grayish brown, with or without black markings. 61. Bill under 2.00 b2. Bill over 2.00 II. Wing under 15.00. 1. Tail pure white.
A. Head and throat slaty black. a. Outer primary black or mostly black. a¹. Outer primary entirely black 43. ICELAND GULL (Im.). 42. GLAUCOUS GULL (Im.). a2. Inner half of inner webs of first primary white. 6. Outer primary mostly white. 61. Tip of first primary white 62. Tip of first primary black 58. LAUGHING GULL. 62. SABINE'S GULL. 59. FRANKLIN'S GULL. 60. BONAPARTE'S GULL.
B. Head white, sometimes washed with pearl-gray. a. Wings white b. Primaries with more or less black. 61. Wing over 11.00. 62. Hind toe very small, without a nail 63. Hind toe normal, with a nail c1. Wing under 11.00 2. Tail marked with black.
A. Wing over 13.25. a. Primaries mostly white b. Primaries black or mostly black B. Wing under 13.25. a. Hind toe very small, without a nail b. Hind toe normal, with a nail. 61. Tarsus 1.50 or over 01. Tarsus under 1.50. 39. IVORY GULL. 54. RING-BILLED GULL. 40. KITTIWAKE. . 61. Ross's GULL. 54. RING-BILLED GULL (Im.). 39. IVORY GULL (Im.). . 40. KITTIWAKE (Im.). . 58. LAUGHING GULL (Im.). 60. BONAPARTE'S GULL (Im.). c2. Secondaries pearl color, tail square. cs. Secondaries mostly white, tail rounded. 61. ROSS'S GULL (Im.). 39. Gavia alba (Gunn.). IVORY GULL. Ad. - Entire plumage pure white; bill yellow, feet black. Im.-Similar to ad., but the wing and tail GULLS. feathers, and sometimes the wing-coverts, with a black spot at their tips. L., 17.00; W., 13-25; T., 5.50; B., 1.35.
Range." Arctic seas, south in winter on the Atlantic coast of North America to Labrador and Newfoundland, casually to New Brunswick, and on the Pacific side to Bering Sea" (A. O. U.).
Long Island, A. V., one record.
Nest, of grass, moss, and feathers on rocky cliffs. Eggs, light yellowish olive, marked with small blotches of brown and larger cloudings of lilac, 2.45 x 1.70 (Brewer). "The Ivory Gulls appear to spend most of the time amid the packice, often at a long distance from land" (Chamberlain). a b C d e FIG. 60. First primaries of adult Gulls, seen from below: (a) Am. Herring Gull; (b) Ring-billed Gull; (c) Laughing Gull; (d) Franklin's Gull; (e) Bonaparte's Gull. 40. Rissa tridactyla (Linn.). KITTIWAKE. Ad. in summer.-Head, neck, tail, and under parts pure white; back and wings pearl-gray; outer web of first primary and 3.00 of the ends of first and second primaries black; GULLS. third to fifth primaries black at the ends and with white tips; hind toe very small, a mere knob without a nail; bill yellowish, feet black. Ad. in winter. -Similar to above, but the top of the head and back of the neck washed with pearl-gray, and a dark spot about the eye. Im. - Similar to winter adults, but with the back of the neck, lesser wing-coverts, and part of the tertials black; tail, except outer pair of feathers, with a black band at its tip; four outer primaries black, except the inner half or more of their inner webs; fifth and sixth tipped with black and white; bill black, feet yellowish. L., 16.00; W., 12:00; T., 4·50; B., 1.30.