These birds are slender and graceful in form and flight, but are the real pirates of bird life, especially among the terns and gulls. This species has two color phases regardless of sex or age. In the light plumage the top of the head is black, rest of the bird brownish. Easily identified by the lengthened central tail-feathers.
Nest.—Two olive brown eggs spotted with black (2.20 × 1.70).
PARASITIC JAEGER. 37. Stercorarius parasiticus. 17 inches.
This bird has the two phases of color similar to the last. The two central tail-feathers are longer and more pointed, projecting about four inches beyond the others. All of the Jaegers have grayish blue legs with black feet, and brown eyes.
Nest.—A slight hollow in the marshy ground in which the two brownish eggs are laid (2.15 × 1.65).
Range.—Northern part of North America, south in winter to southern California, breeding in the Arctic regions.
LONG-TAILED JAEGER. 38. Stercorarius longicaudus. 20 inches.
This is the most swift and graceful of this family in flight. Similar to the last species, but the central pointed tail-feathers extend eight or ten inches beyond the others. It is more often found in the lighter phase.
Nest.—Their eggs are either laid on the bare ground or in a slight depression, scantily lined with grass (2.10 × 1.50).
Range.—Arctic America; south in winter to South America.
IVORY GULL. 39. Pagophila alba. 17 inches.
The little Snow Gull, as it is often called, in the breeding season is entirely white; the bill is tipped with yellow and there is a red ring about the eye.
Nest.—Of grasses and seaweed, on the cliffs in the Arctic regions. Three grayish buff eggs are laid marked with brown and black (2.30 × 1.70).
Range.—North of the Arctic Circle, and winters south to British Columbia.
PACIFIC KITTIWAKE. 40a. Rissa tridactyla pollicaris. 16 inches.
These birds breed in immense rookeries on some of the islands in the Bering Sea.
Nest.—On almost inaccessible cliffs, made of sticks, moss and seaweed, making the interior cup-shaped, to hold the two or three eggs, which are buffy brown or grayish, spotted with darker shades of brown (2.20 × 4.70).
Range.—Coast of the North Pacific, wintering as far south as Lower California.