The martin, or house-martin, is as common and widely diffused in the British Islands as the swallow, and as it lives with man in the same way, making use of houses to build its nest on, it shares the affection with which that bird is generally regarded. Most people, in fact, regard them as one and the same species; for both are of one type, and are domestic in habit, and associate together, and unless looked at with attention they are not seen distinctly, and consequently not distinguished. The martin differs from the swallow in its slightly smaller size; in having its feet feathered and the rump and entire under parts pure white; and in its less sharply forked tail and shorter wings. On the wing it is not so perfectly free as the swallow: it cannot double so quickly, nor fly with such speed and grace. The martin cannot be called a songster. His most common expression is a somewhat harsh note, often uttered as he sports with his fellows in the air; in the pairing and nesting time he occasionally attempts to sing, usually when clinging to a wall and to the rim of his nest, and emits a slight warbling sound, somewhat guttural, and so low that it can only be heard at a distance of a few yards. He arrives in this country a little after the swallow, and immediately sets about making a new nest or repairing an old one. This is formed outwardly of mud or clay, and is placed under the eaves of a house, against the wall. He is able to build against a smooth brick or stucco wall, but prefers stone, which has a rougher surface. It is usual to find several nests near together, and the reason is, probably, that the surface of the wall is suitable to build on, and not, as is often stated, because the martins prefer to nest close to each other. The outer shell of the nest, like that of the swallow, is formed of mud or clay, mixed with hairs and fibres to strengthen it, and is placed against the wall at the side and the projecting eaves above, and forms a half or a portion of a hemisphere, a small opening being left at the top for entrance. The lining is composed of feathers and a little dry grass. Four or five pure white, unspotted eggs are laid. Two broods, and often three, are reared in the season. For some days after the young are able to fly the whole family roost at night in the nest. The young of the first brood, as in the case of the swallow, are the first to migrate. The old birds and the young of the later broods take their departure about the middle of October. Sand-Martin. Cotile riparia. Upper parts, cheeks, and a broad bar on the breast mouse-colour; throat, fore part of the neck, belly, and under tail-coverts white. Legs and feet naked, with the exception of a few small feathers near the insertion of the hind toe; tail forked, rather short. Length, five inches. * * * * *