The Skuas are an interesting group of Gull-like birds that live mainly by robbing Gulls, Terns', and Petrels of their food. Bold, active, and armed with a strong bill and sharp claws, a Skua pounces on other sea-birds and forces them to drop any fish or other food they may have secured, and this food is seized by the robber often before it reaches the water. At times Skuas feed on eggs, on young or sickly birds, or on small mammals. They are dark-coloured birds, and breed in high latitudes, laying as a rule two olive eggs spotted with brown.
The bill somewhat resembles that of Gulls in shape, but is considerably broader at the base ; the culmen is greatly curved at the tip, and the upper mandible bent over the end of the lower; but there is a well-developed horny cere extending more than half the length of the bill, and with the anterior part of its lower border overhanging the nostrils. The lower mandible is straight, and the angle very near the end. The claws are greatly curved and very sharp, the anterior toes long and fully webbed, hind toe small, and the tarsus strong and shielded in front. Wings long and pointed, 1st long quill longest; tail long and rounded, with the two middle feathers projecting beyond the others, sometimes for several inches. Skuas are distinguished from Gulls by having well-developed functional caeca, and by having only one notch on each side of the posterior margin of the sternum.
The Skuas have been divided into two genera on account of slight differences in the bill and tail; but the only two species satisfactorily identified as occurring within Indian limits belong to the same genus.