The SOCIAL WEAVER BIRD (_Philetaërus socius_) stands alone in the peculiarities that distinguish it from its congeners. This species is recognisable by its conical and elongated beak, which is somewhat compressed at the sides; its upper mandible rises into a slight arch, and is furnished at its edges with a tooth-like appendage; the wings are of moderate length, scarcely extending beyond the root of the tail: their first quill is much shorter than the succeeding four, which are of equal length; the tail is rounded at its extremity. In this species, as in the whole family of Weaver Birds, the tarsus is strong and high. The plumage is extremely simple: the top of the head, sides, and front of the neck and breast are of uniform deep grey; the upper part of the head marked with dark spots; the nape and back grey, with undulating lines of black; the wing-covers, quills, and tail-feathers deep brown, edged with light grey; the feathers on the sides of the belly are blackish, bordered with a paler shade; the region of the beak and a small spot over each eye are black; and the beak and legs horn colour. Its length is about six inches and nine lines, and the wing measures rather more than two inches and ten lines. The female is known by the paler colour of the back, and the young by the brown tints upon the head; the latter are without the black spot upon the lower mandible and sides of the body. It is generally considered that the Social Weaver Bird never crosses the Orange river, though how far it may penetrate in a northerly direction has not as yet been ascertained. Patterson, who wrote at the end of the last century, mentions having seen mimosa forests densely inhabited by these birds, who congregate in the hope of preserving their eggs from the numerous snakes. For this purpose, hundreds of them build their nests beneath one large roof, resembling a thatched house in its appearance. This roof (see p. 168) is fixed to a large branch or portion of the tree, and under it the actual nests are placed so closely together that it would be quite impossible for a snake or any other enemy to penetrate to the interior. All day long the busy crowd of workers hurry to and fro, resembling a swarm of bees in their industry, and, like them, return laden with everything needful for the construction or improvement of their homes, while year by year the settlement increases in size, until at last the tree literally bends beneath the weight of the superincumbent colony. The entrances to the interior are very numerous, and situated underneath the massive edifice, each opening leading to a kind of corridor or street, on both sides of which are the small and very secure apartments provided for the young. These birds subsist upon the seeds of the grasses employed in the construction of their dwellings. The above account has been verified by Mr. A. Smith, a well-known traveller and naturalist, from whom we learn that each couple works at its own portion