Often during summer in the Arctic regions one hears a penetrating shriek in the air. When one inquires into the reason of this, it is found to proceed from a kittiwake, more rarely from a glaucous gull, eagerly pursued by a bird as large as a crow, dark-brown, with white breast and long tail-feathers. It is _labben_, the common skua (_Lestris parasitica_, L.), known by the Norwegian walrus-hunters under the name of _tjufjo_, derived from the bird's cry, "_I-o i-o_," and its shameless thief-nature. When the "tjufjo" sees a kittiwake or a glaucous gull fly off with a shrimp, a fish, or a piece of blubber, it instantly attacks it. It flies with great swiftness backwards and forwards around its victim, striking it with its bill, until the attacked bird either drops what it has caught, which is then immediately snapped up by the skua, or else settles down upon the surface of the water, where it is protected against attack. The skua besides eats eggs of other birds, especially of eiders and geese. If the eggs are left but for a few moments unprotected in the nest, it is immediately to the front and shows itself so voracious that it is not afraid to attack nests from which the hatching birds have been frightened away by men engaged in gathering eggs only a few yards off. With incredible dexterity it pecks a hole in the eggs and sucks their contents. If speed is necessary, this takes place so quickly and out of so many eggs in succession that it sometimes has to stand without moving, unable to fly further until it has thrown up what it had swallowed. The skua in this way commonly takes part in the plundering of every eider island. The walrus-hunters are very much embittered against the bird on account of this intrusion on their industry, and kill it whenever they can. The whalers called it "struntjaeger"--refuse-hunter--because they believed that it hunted gulls in order to make them void their excrements which "struntjaegeren" was said to devour as a luxury. [Illustration: A. THE COMMON SKUA. Swedish, Labben, (Lestris parasitica, L.) B. BUFFON'S SKUA. Swedish, Fjellabben. (Lestris Buffonii, Boie.) C. THE POMARINE SKUA. Swedish, Bredstjertade Labben (Lestris pomarina. Tem.) ] The skua breeds upon low, unsheltered, often water-drenched headlands and islands, where it lays one or two eggs on the bare ground, often without trace of a nest. The eggs are so like the ground that it is only with difficulty that they can be found. The male remains in the neighbourhood of the nest during the hatching season. If a man, or an animal which the bird considers dangerous, approaches the eggs, the pair endeavour to draw attention from them by removing from the nest, creeping on the ground and flapping their wings in the most pitiful way. The bird thus acts with great skill a veritable comedy, but takes good care that it is not caught.