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arises from the aurelia of the Lepidoptera ordo, which furnish them with a plentiful table in the wilderness.
TO THE HONOURABLE DAINES BARRINGTON.
As the swift or black martin is the largest of the British hirundines, so is it undoubtedly the latest comer. For I remember but one instance of its ap
pearing before the last week in April; and in some of our late frosty, harsh springs, it has not been seen till the beginning of May. This species usually arrives in pairs.
The swift, like the sand-martin, is very defective in architecture, making no crust, or shell, for its nest; but forming it of dry grasses and feathers, very rudely and inartificially put together. With all my attention to these birds, I have never been able once to discover one in the act of collecting or carrying in materials : so that I have suspected (since their nests are exactly the same) that they sometimes usurp upon the house-sparrows, and expel them, as sparrows do the house and sand-martin; well remembering that I have seen them squabbling together at the entrance of their holes ; and the sparrows up in arms, and much disconcerted at these intruders. And yet I am assured by a nice observer in such matters, that they do collect feathers for their nests in Andalusia ; and that he has shot them with such materials in their mouths.
Swifts, like sand-martins, carry on the business of nidification quite in the dark, in crannies of castles, and towers, and steeples, and upon the tops of the walls of churches under the roof ; and therefore cannot be so narrowly watched as those species that build more openly; but, from what I could ever observe, they begin nesting about the middle of May; and I have remarked, from eggs taken, that they have sat hard by the gth of June. In general they haunt tall buildings, churches, and steeples, and breed only in such : yet in this village some pairs frequent the lowest and meanest cottages, and educate their young under those thatched roofs. I remember but one instance where they bred out of buildings; and that was in the sides of a deep chalkpit near the town of Odiham, in this county, where I have seen many pairs entering the crevices, and skimming and squeaking round the precipices.
As I have regarded these amusive birds with no small attention, if I should advance something new and peculiar with respect to them, and different from all other birds, I might perhaps be credited ; especially as my assertion is the result of many years' exact observation. The fact that I would advance is, that swifts propagate on the wing: and I would wish any nice observer, that is startled at this supposition, to use his own eyes, and I think he will soon be convinced. In another class of animals, viz. the insect, nothing is so common as to see the different species of many genera in conjunction as they fly. The swift is almost continually on the wing ; and as it never settles on the ground, on trees, or roofs, would seldom find opportunity for amorous rites, was it not enabled to indulge them in the air. If any person would watch these birds of a fine morning in May, as they are sailing round, at a great height from the ground, he would see, every now and then, one drop on the back of another, and both of them sink down together for many fathoms with a loud piercing shriek. This I take to be the juncture when the business of generation is carrying on.
As the swift eats, drinks, collects materials for its nest, and, as it seems, propagates on the wing, it appears to live more in the air than any other bird, and to perform all functions there save those of sleeping and incubation.
This hirundo differs widely from its congeners in laying invariably but two eggs at a time, which are milk-white, long, and peaked at the small end; whereas the other species lay at each brood from four to six. It is a most alert bird, rising very early and retiring to roost very late ; and is on the wing in the height of summer at least sixteen hours. In the longest days it does not withdraw to rest till a quarter before nine in the evening, being the latest of all day birds. Just before they retire whole groups of them assemble high in the air, and squeak, and shoot about with wonderful rapidity. But this bird is never so much alive as in sultry thundery weather, when it expresses great alacrity, and calls forth all its powers. In hot mornings, several, getting together in little parties, dash round the steeples and churches, squeaking as they go in a very clamorous manner: these, by nice observers, are supposed to be males serenading their sitting hens; and not without reason, since they seldom squeak till they come close to the walls or eaves, and since those within utter at the same time a little inward note of complacency.
When the hen has sat hard all day, she rushes forth for a few minutes, just as it is almost dark, to stretch and relieve her weary limbs, and snatch a scanty meal, and then returns to her duty of incubation. Swifts, when wantonly and cruelly shot while they have young, discover a lump of insects in their mouths, which they pouch and hold under their tongue. In general they feed in a much higher district than the other species; a proof that gnats and other insects do also abound to a considerable height in the air: they also range to vast distances; since locomotion is no labour to them, who are endowed with such wonderful powers of wing. Their powers seem to be in proportion to their levers ; and their wings are longer in proportion than those of almost any other bird. When they mute, or ease themselves in fight, they raise their wings, and make them meet over their backs.
At some certain times in the summer I had remarked that swifts were hawking very low for hours together over pools and streams; and could not help inquiring into the object of the pursuit that induced them to descend so much below their usual range. After some trouble I found that they were taking phryganea, ephemera and libellulæ (caddis-flies, mayflies, and dragon-flies) that were just emerged from their aurelia state. I then no longer wondered that they should be so willing to stoop for a prey that afforded them such plentiful and succulent nourishment.