The cawing of the rooks in February shows that the time is coming when their nests will be re-occupied. They resort to the trees, and perch above the old nests to indicate their rights; for in the rookery possession is the law, and not nine-tenths of it only. In the slow dull cold of winter even these noisy birds are quiet, and as the vast flocks pass over, night and morning, to and from the woods in which they roost, there is scarcely a sound. Through the mist their black wings advance in silence, the jackdaws with them are chilled into unwonted quiet, and unless you chance to look up the crowd may go over unnoticed. But so soon as the waters begin to make a sound in February, running in the ditches and splashing over stones, the rooks commence the speeches and conversations which will continue till late into the following autumn. The general idea is that they pair in February, but there are some reasons for thinking that the rooks, in fact, choose their males at the end of the preceding summer. They are then in large flocks, and if only casually glanced at appear mixed together without any order or arrangement. They move on the ground and fly in the air so close, one beside the other, that at the first glance or so you cannot distinguish them apart. Yet if you should be lingering along the by-ways of the fields as the acorns fall, and the leaves come rustling down in the warm sunny autumn afternoons, and keep an observant eye upon the rooks in the trees, or on the fresh-turned furrows, they will be seen to act in couples. On the ground couples alight near each other, on the trees they perch near each other, and in the air fly side by side. Like soldiers each has his comrade. Wedged in the ranks every man looks like his fellow, and there seems no tie between them but a common discipline. Intimate acquaintance with barrack or camp life would show that every one had his friend. There is also the mess, or companionship of half a dozen, or dozen, or more, and something like this exists part of the year in the armies of the rooks. After the nest time is over they flock together, and each family of three or four flies in concert. Later on they apparently choose their own particular friends, that is the young birds do so. All through the winter after, say October, these pairs keep together, though lost in the general mass to the passing spectator. If you alarm them while feeding on the ground in winter, supposing you have not got a gun, they merely rise up to the nearest tree, and it may then be observed that they do this in pairs. One perches on a branch and a second comes to him. When February arrives, and they resort to the nests to look after or seize on the property there, they are in fact already paired, though the almanacs put down St. Valentine's day as the date of courtship.