The petrels do not arrive at their breeding-grounds until about the middle of June. They have colonies on the Scilly Islands, and at various other points on the west coast to St. Kilda, and the Orkneys and Shetlands. A few small colonies are also found on some of the islands on the Irish coast. The birds breed in holes in stone walls and piles of loose stones, and, in some localities, in old rabbit-burrows and holes in banks. A single egg is laid, on a slight bed of grass; it is very large for the bird’s size, rough in texture, pure white, and in most cases thinly sprinkled with minute reddish brown specks. The young birds are fed at night, and may then be heard faintly clamouring for food after dark. * * * * * The fork-tailed, or Leach’s petrel (_Procellaria leucorrhoa_), is a larger bird than the last, being about the same size as the swift. It is a much rarer species than the stormy petrel, and has only two known breeding-places in the United Kingdom, one at St. Kilda, the other on the island of North Rona, off the west coast of Scotland. On all other parts of the British coast it is known only as a storm-driven straggler. The birds breed in June, in holes which they make in the soft peaty soil to a depth of two or three feet, or deeper. A slight nest of dry grass is made, and a single egg deposited, pure white in colour, with a zone of small reddish spots at the large end. During the daytime the birds remain silent in their holes; in the evening they become active and garrulous. * * * * * Wilson’s petrel (_Oceanites oceanicus_), a bird about the size of a swift, with a black plumage and white rump, appears occasionally as a straggler in the British Islands. Its only known breeding-grounds are in the southern hemisphere. Manx Shearwater. Puffinus anglorum. [Illustration: FIG. 113.--MANX SHEARWATER. ⅛ natural size.] Bill blackish; legs and feet yellowish flesh-colour; crown, nape, and upper parts sooty black; under parts white; sides of neck mottled with greyish brown. Length, fifteen inches. * * * * *