My house is shaded by two great plane-trees; their branches reach the roof, on which generations of Sparrows, too many for the welfare of my cherries and my peas, succeed one another throughout the warm weather. This vast mass of greenery is the first stopping-place after the exodus from the nest begins. Here the young birds assemble and for hours chatter and scream before flying off on their pilfering-expeditions; here the well-filled squads take their stand on returning from the fields. The adults meet here to keep an eye on their recently-emancipated offspring, to caution the imprudent and encourage the timid; family-quarrels are fought out here and the events of the day discussed. From morning till evening there is a continual going to and fro between the roof and the plane-trees. Well, in spite of these constant visits, I have only once, in the past twelve years, seen the Sparrow build his nest in the branches. The couple that decided in favour of a mid-air nest on one of the plane-trees were not particularly satisfied, it seems, with the results obtained, for they did not repeat the experiment next year. Since then, none has placed before my eyes for the second time a big ball of a nest swaying in the wind at the end of a branch. The steadier and less costly shelter of the tile is preferred. We now know enough about the early art of the Sparrow. What will the Swallows tell us in their turn? Two species frequent our dwellings: the Window-swallow (Hirundo urbica) [51] and the Chimney-swallow (H. rustica), both of whom are very badly named, both in the scientific and the everyday language. Those epithets of urbica and rustica, which make a town-dweller of the first and a villager of the second, can be applied indifferently to either, since they both take up their abode at one time in the town, at another in the village. The terms window and chimney possess a precise meaning which is rarely confirmed and very often contradicted by the facts. For the sake of clearness, the supreme condition of all tolerable prose, and to confine myself to the habits peculiar to the two species in my part of the world, I will call the first the Wall-swallow and the second the Domestic Swallow. The shape of the nest constitutes the most striking difference. The Wall-swallow gives his the form of a ball, with a round aperture just large enough to admit the bird. The Domestic Swallow fashions his into a cup with a wide opening.