SWALLOW, the Common, or Chimney-swallow, Hirundo rustica, L. a well-known bird of passage, appearing in this country about the middle of April, and generally departing early in October. This bird constructs its nest, about the middle of May, in the upper part of chimnies. The female deposits from 4 to 6 white eggs, spotted with red, producing her first brood about the latter end of June, or beginning of July; and the second in August.
Swallows delight to skim along avenues, extensive walks, under hedges, pasture fields, and mown meadows; because, in such situations, flies and gnats generally abound. They also frequently settle on newly-ploughed gravelly soils, particles of which they instinctively swallow, for promoting the digestion of their food. These birds are caught, and sold as food, in the markets of France, Spain, and Italy; but not in Britain. By the myriads of insects which every single brood of swallows destroys in the course of a summer, they, in a great measure, defend mankind from the annoyance of flies, gnats, &c. Farther, by devouring multitudes of vermin, either in the grub, or winged state, which would otherwise render the labours of the husbandman abortive, the breed of these birds ought, by every possible means, to be encouraged.
It is remarkable, that some species of these useful creatures retire to warmer climates, while others remain during the winter at the bottom of swamps and morasses, in a torpid state, till they are recalled into life by the genial warmth of the vernal sun.