The BLUE ROCK WAGTAIL, or BLUE THRUSH (_Petrocincla cyana_), is rather larger than the species last mentioned, being from eight inches and three-quarters to nine inches and a half long, and fourteen broad; the wing measures five and the tail three inches and a half. The plumage of the male is of an uniform greyish blue, and the quills and tail-feathers edged with blue. The female is blueish grey upon the upper part of the body, the throat being decorated with light reddish brown spots, each of which is surrounded by a dark line; the feathers on the under side are edged with brownish white, and marked with dark brown crescent-shaped patches; the quills and tail-feathers are also dark brown. The nestlings resemble the mother, but have light brown spots upon the back; the eyes of all are brown, and the beak and feet black. After the moulting season all the feathers in the plumage of the male are of an uniform greyish blue, and the quills and tail-feathers edged with blue. The Blue Thrushes inhabit the whole of Southern Europe, Northern Africa, and a portion of Central Asia, and are especially numerous in Greece, Dalmatia, Italy, the South of France, Spain, Egypt, and Algiers; during winter a few are occasionally seen in India, but these, no doubt, are stragglers that have lost their way, as, for the most part, these birds remain throughout the entire year in their native land. Like the species last described, they principally occupy rocky valleys and mountainous regions, but are also often to be seen about towns and villages, where they perch upon steeples, roofs, or lofty walls; in Egypt they frequently dwell within the ruins of ancient temples. Although sprightly and active, they are remarkably unsocial, and exhibit a positive dislike to the society not only of man and of birds in general, but of their own kind. During the period of incubation alone do they associate even in pairs; at other seasons each leads an entirely independent life, and exhibits active hostility to every other member of the feathered creation. The flight of this species is much more continuous than that of its congeners, and it usually hovers before perching: like the Thrush, it often soars into the air when about to pour forth its song. Upon the ground it moves with great ease and rapidity. The voice of the Blue Thrush, though inferior to that of the Rock Wagtail, is pleasing, and so flexible as readily to imitate the notes of other birds. The evolutions performed by the male for the delectation of his mate are even more comical than those indulged in by the _Petrocincla saxatilis_, as the little creature inflates his body until it is almost as round as a ball, bows his head, and continually brandishes his tail aloft whilst engaged in going through his dancing steps. The nest is situated in holes in rocks, walls, and ruins, or upon lofty towers or steeples, and is rudely formed of grass; nevertheless, its flat interior is neatly lined with fibres.