Slender gull-like seabird; the middle-sized of the three jaegers. Breeds on Arctic tundra; spends the rest of the year at sea. Difficult to separate from other jaegers. Breeding adults have a long pointed tail (not as long as Long-tailed Jaeger). Plumage varies from entirely dark blackish-brown to paler with white belly and yellowish on the side of the neck. Immature birds are variable but usually warm brown with cinnamon barring on wings. Barring on underwing and undertail is weaker than on Pomarine Jaeger. Shape and flight style are intermediate between Pomarine and Long-tailed. Typically shows white shafts on four to six outermost wing feathers, more than Long-tailed, but less than Pomarine. Bill is relatively long and slender. All jaegers chase other birds and steal their food.