The ROCK SPARROW (_Petronia rupestris_) is most undoubtedly to be classed with the preceding birds, though differing from them in shape, colour, and habits. The body is compact, its length six and a quarter inches, and breadth across the wings nine and a half inches, the female somewhat less. The beak is comparatively strong, and the plumage very plain, resembling that of the female House Sparrow. The back is greyish brown, marked with blackish-brown and greyish-white spots; the upper tail-covers grey, and striped, as is the forehead, with olive brown; over the eyes passes a lighter streak, and the tail-feathers have a white spot on the under side. In winter the beak is of a brownish grey, in summer of a yellow tint, the upper mandible being darker than the under; the eyes are brown, and the tarsus reddish grey. There is but little difference in the appearance of the sexes after they have attained maturity, and females are often found as beautifully marked as the male. The young are recognisable by a white spot upon the throat. In the South of France, Spain, Algiers, and the Canary Islands, the Rock Sparrow is extremely common. It is found principally in mountainous districts, among old ruins, but is often met with near towns or villages, and in lonely valleys; it is by no means afraid of man, though it but rarely comes down into the streets, preferring to remain in the retreats it has chosen in cliffs or old towers, until compelled by hunger to seek its food in the adjacent fields. Above all other things it prizes liberty, and exhibits a foresight and prudence in its intercourse with our race that distinguishes it in a remarkable degree from the rest of its congeners. In its movements the Rock Sparrow bears a considerable resemblance to the Cross-bill; its flight is produced by a short, quick vibration of the wings, upon which it poises itself with a hovering motion before perching. It hops nimbly upon the ground, and while sitting assumes a defiant attitude, and wags its tail repeatedly. The voice of this bird might almost be termed a song, and is not unlike that of the Bullfinch, though by no means so agreeable or varied. The breeding season commences at the end of spring, or the beginning of summer. This species builds in holes in rocks, walls, or roofs, and with so much precaution are their retreats selected that it is extremely difficult to find a nest. The one we saw was constructed of straws and bits of cloth and linen, carelessly intermixed, and lined with feathers, hair, and wool. One of these little cradles is often used for years by the same birds, who make whatever improvements are necessary as spring returns. The eggs, which are five in number, are larger than those of the generality of Sparrows, and of a greyish or dirty white, spotted and streaked with slate colour, the markings being most numerous at the broad end. We are unable to speak with certainty as to whether both parents brood, although