The Sparrow shall tell us first how his nest-building art stood in the days when there were no lodgings in walls and roofs. A hollow in a tree, high enough to shelter him from prying eyes, with a narrow mouth to keep out the rain and a fairly generous cavity, gives him an excellent dwelling, of which he readily avails himself even when there are plenty of old walls and roofs in the neighbourhood. The youngest bird’s-nester in my village knows all about it and abuses his knowledge. The hollow tree then is one lodging which the Sparrow employed, long before using Evander’s cabin and David’s stronghold on the rock of Zion.
His architectural resources go even further. His shapeless mattress, an incoherent jumble of feathers, down, flock, straw and other incongruous materials, seems to demand a broad and stable support. The Sparrow laughs at the difficulty and, from time to time, for reasons that remain hidden from me, he conceives a bold plan: he decides to build a nest having no support but that of three or four tiny branches at the top of a tree. The clumsy maker of [[139]]mattresses tries to obtain aerial suspension, a swinging house, the prerogative of weavers and basket-makers well-versed in the art of plaiting. And he succeeds.
In the fork of a few branches he accumulates everything suitable for his work that he can pick up near a house: rags, scraps of paper, ends of thread, flocks of wool, bits of hay and straw, dry blades of grass, flax dropped from the distaff, strips of bark retted by lying long in the open; and of his various gleanings, clumsily matted together, he contrives to make a large, hollow ball with a narrow opening in the side. It is bulky to a degree, the thickness of the dome having to be as good a defence against the rain as the shelter of a tile would be; it is very roughly constructed, without any attempt at artistry; but, when all is said, it is stout enough to last for a season. This is how the Sparrow must have worked in the beginning, when there was no hollow tree at hand. Nowadays, that primitive art, too costly in time and materials, is seldom practised.
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, [[140]]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 [[141]]of the Sparrow. What will the Swallows tell us in their turn? Two species frequent our dwellings: the Window-swallow (Hirundo urbica)[3] 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. [[142]]
The Wall-swallow, who is much less common than the other, never chooses a site within our houses for his structure. It must be outside for him and it must stand high, far removed from inquisitive eyes; but at the same time a shelter against the rain is indispensable, for the damp is almost as dangerous for his mud nest as for that of the Pelopæus. He therefore settles by choice under the eaves and cornices of buildings. He visits me every spring. My house pleases him. Just below the roof is a cornice made up of a few courses of ordinary “half-round” coping-tiles, corbelled out from the face of the wall in such a way as to give a long line of round-headed niches which are sheltered from the rain and enjoy plenty of sunshine on the south front. Among all these nooks, so healthy, so well-protected and moreover so excellently adapted to the shape of the nest, the bird has only to choose. There is room for all, however numerous the colony may become one day.
Apart from sites of this kind, I see none approved by the Swallow in the village, except the under part of a few cornices of the church, which is the only edifice of a monumental character. In short, the support of [[143]]a wall, in the open air, with some shelter against the rain, is all that the Swallow asks of our buildings.
But the natural wall is a perpendicular rock. If the bird here finds overhanging projections, forming a penthouse, it must adopt them as the equivalent of the ledge of our roofs. Ornithologists know, in fact, that in mountainous districts, far removed from human dwellings, the Wall-swallow builds against the vertical sides of the rocks, so long as his ball of clay is under cover of some kind.
Near where I live are the Gigondas Mountains, the most curious geological structure that I have ever seen. Their long chain displays so steep a slope that it is almost impossible to stand upright near the summit; and the ascent of the accessible part has to be made on all-fours. You then find yourself at the foot of a perpendicular cliff, an enormous slab of sheer rock which, like some Titanic rampart, tops the precipitous ridge with a jagged crest. The people of the country call this Cyclopean wall les Dentelles. I was one day botanizing at its base, when my eyes were attracted by the evolutions of a flock of birds in front of the rugged face of the rock. I [[144]]easily recognized the Wall-swallow: his silent flight, his white belly and his ball-shaped nest fastened to the cliff told me all about him. I in my turn now learnt, apart from the books, that this species fixes its nests to perpendicular rocks when the cornices of our buildings and the ledges of our roofs are missing. Even so must it have nested in the ages that preceded our stone structures.
The problem becomes thornier with the second species. The Domestic Swallow, who has much more confidence in our hospitality and is also perhaps more susceptible to cold, establishes himself as often as possible inside our houses. The embrasure of a window, the under surface of a balcony will satisfy his requirements at need; but he prefers the shed, the loft, the stable or an empty room. His familiarity even reaches the point of cohabitation with man in the same apartment. No more timid than the Pelopæus in taking possession of the premises, he installs himself in the farm-kitchen and builds upon the peasant’s smoke-blacked rafters; more venturesome even than the pot-making insect, he appropriates the drawing-room, the study, the bedroom or any well-kept chamber [[145]]that leaves him at liberty to come and go.