miles from home towards the coast, the sun broke out into a delicate warm day. We were then on a large heath or common, and I could discern, as the mist began to break away, great numbers of swallows (hirundines rustica) clustering on the stunted shrubs and bushes, as if they had roosted there all night. As soon as the air became clear and pleasant, they all were on the wing at once; and, by a placid and easy flight, proceeded on southward towards the sea; after this I did not see any more flocks, only now and then a straggler. I cannot agree with those persons that assert that the swallow kind disappear some and some, gradually, as they come, for the bulk of them seem to withdraw at once; only some stragglers stay behind a long while, and do never, there is the greatest reason to believe, leave this island. Swallows seem to lay themselves up, and to come forth in a warm day, as bats do continually of a warm evening, after they have disappeared for weeks. For a very respectable gentleman assured me, that, as The causes influencing the migration of birds appear more difficult to solve, than the possibility of the execution of it. They seem to be influenced by an innate law, which we do not, and cannot, comprehend, though in some measure dependent on the want of food or climate congenial to the sys tems of each, and which acts almost without the will of the individual. Neither this, however, nor the duties incumbent on incubation, can be the only exciting causes, as we may judge by the partial migrations of some to different parts of the same country, where food and the conveniences for breeding are alike; by the partial migration only, of a species from one country to another, differing decidedly in temperature, and where the visiting species thrives equally with the resident one; and by the males of some species migrating, while the females remain.-W. J. he was walking with some friends under Mertonwall, on a remarkably hot noon, either in the last week in December or the first week in January, he espied three or four swallows huddled together on the moulding of one of the windows of that college. I have frequently remarked that swallows are seen later at Oxford than elsewhere; is it owing to the vast massy buildings of that place, to the many waters round it, or to what else? When I used to rise in a morning last autumn, and see the swallows and martins clustering on the chimneys and thatch of the neighbouring cottages, I could not help being touched with a secret delight, mixed with some degree of mortification: with delight to observe with how much ardour and punctuality those poor little birds obeyed the strong impulse towards migration, or hiding, imprinted on their minds by their great Creator; and with some degree of mortification, when I reflected that, after all our pains and enquiries, we are yet not quite certain to what regions they do migrate; and are still farther embarrassed to find that some do not actually migrate at all. These reflections made so strong an impression on my imagination, that they became productive of a composition that may perhaps amuse you for a quarter of an hour when next I have the honour of writing to you. XXIV. THE Scarabæus fullo I know very well, having seen it in collections; but have never been able to discover one wild in its natural state. Mr Banks told me he thought it might be found on the sea-coast. On the 13th of April, I went to the sheepdown, where the ringousels have been observed to make their appearance at spring and fall, in their way, perhaps, to the north or south; and was much pleased to see three birds about the usual spot. We shot a cock and a hen; they were plump and in high condition. The hen had but very small rudiments of eggs within her, which proves they are late breeders; whereas those species of the thrush kind that remain with us the whole year have fledged young before that time. In their crops was nothing very distinguishable, but somewhat that seemed like blades of vegetables nearly digested. In autumn they feed on haws and yew-berries, and in the spring on ivy-berries. I dressed one of these birds, and found it juicy and well-flavoured. It is remarkable that they make but a few days' stay in their spring visit, but rest near a fortnight at Michaelmas. These birds, from the observations of three springs and two autumns, are most punctual in their return; and exhibit a new migration unnoticed by the writers, who supposed they never were to be seen in any of the southern counties. One of my neighbours lately brought me a new salicaria, which, at first, I suspected might have proved your willow-lark,* but on a nicer examination, it answered much better to the description of that species which you shot at Revesby, in Lincolnshire. My bird I describe thus: "It is a size less than the grasshopper-lark; the head, back, and covert of the wings, of a dusky brown, with For this salicaria see Letter XXV. p. 85: out those dark spots of the grasshopper-lark; over each eye is a milk-white stroke; the chin and throat are white, and the under parts of a yellowish white; the rump is tawny, and the feathers of the tail sharp-pointed; the bill is dusky and sharp, and the legs are dusky, the hinder claw long and crooked."* The person that shot it says that it sung so like a reed-sparrow, that he took it for one; and that it sings all night: but this account merits farther enquiry. For my part, I suspect it is a second sort of locustella, hinted at by Dr Derham in Ray's Letters: see p. 74. He also procured me a grasshopper-lark. The question that you put with regard to those genera of animals that are peculiar to America, viz. how they came there, and whence? is too puzzling for me to answer; and yet so obvious as often to have struck me with wonder. If one looks into the writers on that subject, little satisfaction is to be found. Ingenious men will readily advance plausible arguments to support whatever theory they shall choose to maintain; but then the misfortune is, every one's hypothesis is each as good as another's, since they are all founded on conjecture. The late writers of this sort, in whom may be seen all the arguments of those that have gone before, as I remember, stock America from the western coast of Africa, and the south of Europe; and then break down the isthmus that bridged over the Atlantic. But this is making use of a violent piece of machinery: it is a diffi, culty worthy of the interposition of a god! "Incre dulus odi." Sylvia phragmites. Bechst. Sedge-warbler-Selby's Ornith.-W. J. TO THOMAS PENNANT, ESQUIRE. THE NATURALIST'S SUMMEREVENING WALK. equidem credo, quia sit divinitus illis Ingenium. VIRG. GEORG. WHEN day, declining, sheds a milder gleam, The angler's May-fly, the ephemera vulgata, Linn. comes forth from its aurelia state, and emerges out of the water about six in the evening, and dies about eleven at night, determining the date of its fly state in about five or six hours. They usually begin to appear about the 4th of June, and continue in succession for near a fortnight. See Swammerdam, Derham, Scopoli, &c. +Vagrant cuckoo; so called because, being tied down by no incubation or attendance about the nutrition of its young, it wanders without control. Charadrius oedicnemus. |