The dam betakes herself immediately to the business of a second brood as soon as she is disengaged from her first, which at once associates with the first broods of house-martins, and with them congregates, clustering on sunny roofs, towers and trees. This _hirundo_ brings out her second brood toward the middle and end of August. All summer long, the swallow is a most instructive pattern of unwearied industry and affection: for from morning to night, while there is a family to be supported, she spends the whole day in skimming close to the ground, and exerting the most sudden turns and quick evolutions. Avenues, and long walks under the hedges, and pasture-fields, and mown meadows where cattle graze, are her delight, especially if there are trees interspersed; because in such spots insects most abound. When a fly is taken, a smart snap from her bill is heard, resembling the noise at the shutting of a watch-case; but the motion of the mandibles is too quick for the eye. The swallow, probably the male bird, is the _excubitor_ to house-martins and other little birds; announcing the approach of birds of prey. For as soon as a hawk appears, with a shrill alarming note he calls all the swallows and martins about him; who pursue in a body, and buffet and strike their enemy till they have driven him from the village; darting down from above on his back, and rising in a perpendicular line in perfect security. This bird will also sound the alarm, and strike at cats when they climb on the roofs of houses, or otherwise approach the nest. Each species of _hirundo_ drinks as it flies along, sipping the surface of the water; but the swallow alone in general washes on the wing, by dropping into a pool for many times together: in very hot weather house-martins and bank-martins also dip and wash a little. The swallow is a delicate songster, and in soft sunny weather sings both perching and flying; on trees in a kind of concert, and on chimney-tops: it is also a bold flier, ranging to distant downs and commons even in windy weather, which the other species seems much to dislike; nay, even frequenting exposed seaport towns, and making little excursions over the salt water. Horsemen on the wide downs are often closely attended by a little party of swallows for miles together, which plays before and behind them, sweeping around and collecting all the skulking insects that are roused by the trampling of the horses' feet: when the wind blows hard, without this expedient, they are often forced to settle to pick up their lurking prey....