Richardson’s Skua reaches its breeding-grounds in the British Islands early in May. Its haunts at this season are open moors, at no great distance from the sea. Although social at its breeding-places, it can scarcely be described as gregarious, and the nests are usually scattered up and down the moorland area. This Skua appears to pair annually, and the nest, always made upon the ground, is merely a hollow, carelessly lined with a little dry herbage, and sometimes nothing but a shallow cavity in the moss. The eggs, normally, are two, but sometimes three have been found, and occasionally but one. They range from olive to brown in ground colour, spotted and speckled with darker brown and grayish brown. Incubation is performed by the female, and lasts about a month. At its breeding-places Richardson’s Skua is very demonstrative, and often reveals the situation of the nest by its anxious movements above the intruder’s head. After the young are reared the moors are deserted, and for the remainder of the year this Skua is decidedly pelagic in its habits and haunts. We now pass to the Terns. These pretty graceful birds—widely known as “Sea Swallows”—differ in many respects from the Gulls and Skuas. They most closely resemble the former in general appearance, but may be easily distinguished by their slender form, small size, and forked tail. Of the dozen species that have been regarded as “British,” no less than five breed within the limits of our islands. The Terns are far more locally distributed than the Gulls. Many miles of coast may be traversed without one ever seeing a Tern. They are all migratory birds with us, visiting Britain in summer to breed, and retiring south again in autumn. It is only during the season of passage, therefore, that they are at all widely dispersed, for the remainder of their sojourn on our coasts is spent at or in the near vicinity of their breeding-stations. The five indigenous British species follow. SANDWICH TERN.