jaeger, any of three species of seabirds belonging to the genus Stercorarius of the family Stercorariidae. They are rapacious birds resembling a dark gull with a forward-set black cap and projecting central tail feathers. Jaegers are called skuas in Britain, along with the great skua, a larger bird (see skua). Jaegers have two colour phases: all-brown or, more commonly, brown above and white below.
Jaegers nest in Arctic tundra and then go to sea, many as far as Australia and New Zealand. At sea they catch fish on their own; but, while nesting along coasts, they force terns and kittiwakes to disgorge their food, destroy the eggs and young of other seabirds, and capture land birds and rodents.
The largest species is the pomarine jaeger, or pomatorhine skua (Stercorarius pomarinus), 50 cm (20 inches) long. Smallest is the long-tailed jaeger (S. longicaudus), 35 cm (14 inches) long. Intermediate in body size is the parasitic jaeger (S. parasiticus).