pretension to song, but uses a little inward wailing note, when it thinks its young in danger from cats or other annoyances: it breeds but once, and retires early.*

Selborne parish alone can and has exhibited at times more than half the birds that are ever seen in all Sweden: the former has produced more than one hundred and twenty species, the latter only two hundred and twenty-one. Let me add, also, that it has shown near half the species that were ever known in Great Britain.‡

On a retrospect, I observe that my long letter carries with it a quaint and magisterial air, and is very sententious: but when I recollect that you requested stricture and anecdote, hope you will pardon the didactic manner for the sake of the information it may happen to contain.

LETTER LXI.

TO THE HON. DAINES BARRINGTON.

SELBORNE, Sept. 28, 1774. DEAR SIR,-As the swift, or black-martin, is the largest of the British hirundines, so it is undoubtedly the latest comer: for I remember but one instance of its appearing 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

*The muscicapa grisola, Linn.-W. J.

Mr. Yarrell has informed us that near seventy species of birds have been noticed in Kensington Gardens, which considering the situation, as well as the confined nature of the locality, is an unusually great number.-YARRELL'S British Birds.

Sweden 221; Great Britain 252 species.

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 nidifi cation 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 9th 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. We remember but one instance where they breed out of buildings, and that is in the sides of a deep chalk pit near the town of Odiham, in this county, where we 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 tread, or copulate 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, were 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 into 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 just as it is almost dark, and stretches and relieves her weary limbs, and snatches a scanty meal for a few minutes, and then returns to her duty of incubation. Swifts, when wantonly and cruelly shot while they have young, discover a little 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 flight, 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 their pursuit, that induced them to descend so much below their usual range. After some trouble I found that they were taking phryganec, ephemera, libellula (cadew-flies, may-flies, 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.

They bring out their young about the middle or latter end of July; but as these never become perchers, nor, that ever I could discern, are fed on the wing by their dams, the coming forth of the young is not so notorious as in the other species.

On the 30th of last June I untiled the eaves of a house where many pairs build, and found in each nest only two squab, naked pulli. On the 8th of July I repeated the same inquiry, and found they had made very little progress towards a fledged state, but were still naked and helpless; from whence we may conclude, that birds whose way of life keeps them perpetually on the wing, would not be able to quit their nest till the end of the month. Swallows and martins that have numerous families, are continually feeding them every two or three minutes; while swifts, that have but two young to maintain, are much at their leisure, and do not attend on their nests for hours together.

Sometimes they pursue and strike at hawks that come in their way, but not with that vehemence and fury that swallows express on the same occasion. They are out all day long on wet days, feeding about, and disregarding still rain; from whence two things may be gathered, first, that many insects abide high in the air, even in rain; and next, that the feathers of these birds must be well preened to resist so much wet. Windy, and particularly windy weather with heavy showers, they dislike, and on such days withdraw, and are scarcely ever seen.

*

There is a circumstance respecting the colour of swifts, which seems not to be unworthy our attention. When they arrive in the spring. they are all over of a glossy dark soot colour, except their chins, which are white; but, by being all day long in the sun and air, they become quite weatherbeaten and bleached before they depart, and yet they return glossy again in the spring. Now, if they pursue the sun into lower latitudes, as some suppose, in order to enjoy a perpetual summer, why do they not return bleached? Do they not, rather, perhaps, retire to rest for a season, and at that juncture moult and change their feathers, since all other birds are known to moult soon after the season of breeding?

Swifts are very anomalous in many particulars, dissenting from all their congeners, not only in the number of their young, but in breeding but once in a summer; whereas all the other British hirundines breed invariably twice. It is past all doubt that swifts can breed but once, since they withdraw in a short time after the flight of their young, and some time before their congeners bring out their second broods. We may here remark that, as swifts breed but once in a summer, and only two at a time, and the other hirundines twice, the latter, who lay from four to six eggs, increase, at an average, five times as fast as the former.

But in nothing are swifts more singular than in their early retreat. They retire, as to the main body of them, by the 10th of August, and sometimes a few days sooner; and every straggler invariably withdraws by the 20th: while their congeners, all of them, stay till the beginning of October, many of them all through that month, and some occasionally to the beginning of November. This early retreat is mysterious and wonderful, since that time is often the sweetest season in the year. But what is more extraordinary, they begin to retire still earlier in the more southerly parts of Andalusia, where they can be nowise influenced by any defect of heat, or, as one might suppose, defect of food. Are they regulated in their motions with us

Mr. Yarrell says that the swift departs before its moult, and when its plumage is at the worst from wear and tear. Our summer visitors generally complete their moult before they leave us, but not the Hirundinidæ.