But it does not often condescend to walk on the ground. When it alights, to knead the plaster for its nest at a puddle's edge, or for any other purpose, it springs up into the air from the spot on which it settled. And its nest once built, it has no reason for coming to the ground at all. It does so from choice sometimes, where it suspects insects are congregated, or sometimes to drink, but, as a rule, it both eats and drinks on the wing. When it rests, it is on a house-roof, a railing, or dead branch, and often when thus seated it sings a very sweet, simple little song, loud enough to puzzle the passer-by, who can hear but not see the songster, and pretty enough to astonish those who imagine that swallows only twitter. [Illustration: "_Waiting for the signal to start_"] While the hen-bird is brooding she is busily fed by her mate, and the compliments that pass whenever the two birds meet are very sweet to listen to. Every time he comes there is a scrap of conversation, and when she has eaten what he has brought, there is a little exchange of twittered love-nothings. There are always two broods in the year, the first scattering over the country and eventually straggling away in small migratory parties across the sea, the second going with their parents in the great annual exodus in October. It is then that these birds congregate in vast companies, lining the telegraph-wires for miles, till they loop with their weight, or crowding upon every available foothold of some range of buildings. How irresistible the discipline of these little creatures is, as you look at them sitting there by the thousand, waiting for the signal to start on a journey the object and end of which is a mystery to all the young ones. You will see how impatient they are, how they keep on trying their wings by wheeling round in the air. With what restlessness they take short flights and resettle. And all this time, and up to the very last, the old ones keep on busily feeding the young, as if they knew what a trial was before them, and how urgent their need of all the strength possible. Here and there are broods hatched too young to join in the great Hegira, and here and there nestlings with some infirmity that unfits them for boisterous travel. These are found lingering in our islands all through October into November, but the great army of the swallows musters at the rendezvous punctually to date. And there they sit in their myriads, but the whole obedient as one, and lo! next morning, before the sun is up, they are gone, every one of them--gone towards the sea, towards the Nile and the Cape, gone till next Spring. For "the year is overgrown, Summer like a bird hath flown." [Illustration] CHAPTER II