There is yet another cla.s.s of facts to be adduced, which has an important bearing on the subject. At first sight, these facts appear less conclusive than the a.s.serted discoveries of the birds, because less direct; but I am inclined to attach more value to them, because they are attested by so many and so unexceptionable witnesses. I mean the sight of Swallows at large in these islands during the winter months. Let us see some examples.

White of Selborne records several cases: thus, in 1773, twenty or thirty House-martins were playing in the air all day on the 3d of November,[124] after having disappeared from the 22d of October. In 1772, he saw three House-swallows gliding by on the sea-sh.o.r.e at Newhaven, on the 4th of November.[125] On another occasion, (the year not being recorded,) he saw, on a sunny morning, a House-martin flying, at Oxford, on the 20th of November.[126] On the 26th of November 1768, one of his neighbours saw a Martin hawking briskly after flies.[127] And a very respectable gentleman a.s.sured him that on a remarkably hot day, either in the last week in December or the first week in January, he espied three or four Swallows in the moulding of a window of Merton College, Oxford.[128]

Colonel Montagu remarks that "there are a variety of instances of the Swallow and Martin having been seen flying in the months of November and December, roused probably from a state of torpidity by an unusual warmth of the air;"[129] and Captain H. W. Hadfield, commenting on this, affirms that he has "more than once had ocular proof of their presence during the winter months."[130] Yarrell gives examples of the late appearance of the Swift. One was seen by Mr Blackwall on the 20th of October 1815; a second in Perthshire on the 8th of November 1834; and a third in Devonshire, by the Rev. Mr Cornish, on the 27th November 1835.[131] In considering these cases, it is needful to bear in mind that the Swift migrates from this country annually from the 1st to the 15th of August.

Mr C. R. Bree mentions the following case, which I record, not because it was particularly late, but because the state of the season, and some other circ.u.mstances which he remarks on are interesting:--"On the 25th of October 1848, some workmen being engaged on the roof of my house, I was surprised by the appearance of three Swallows flying about the men.

I had not seen one since the beginning of the month. By the side of the edge of the gable-end of the house the plaster was broken away, forming a hole, which led under the roof. While watching the birds, which came occasionally quite close to my face, I saw first one, then another, alight upon the ledge of the gable-end, near the hole. Now, I thought, I am to settle the question of hybernation: but I was disappointed. Though I watched them for several hours--though I sent the workmen to another part of the house, yet, although they frequently settled about the hole, they never entered it. They were evidently young birds, and had been disturbed. One of them rested upon the chimney, and appeared weak and dull. I lost sight of them during the day; but the following morning, the weather being warm, I saw several flying about high up in the air.

There is some mystery about these things. Why have these late appearances been more remarked this year than other years? How did the birds obtain food during the three weeks of bitter cold weather when they were not seen in October?"[132]

On the 10th of December 1843, a specimen of the Swallow, _an adult bird, not a young of the season_, (an important circ.u.mstance,) in full plumage and good condition, was shot at Goole, in the West Riding, and was sent to Mr R. J. Bell, of Derby, a good ornithologist,[133] who records the fact. In 1852, that excellent naturalist, Mr Hewitson, of Oatlands, saw two Chimney-swallows at Eshar on the 18th of November, and on the 21st had four martins about his house.[134] In 1855, Mr E. Vernon Harcourt reports the occurrence of several Martins skimming about at Uckfield on the 23d of November; and on the 6th of December several Chimney-swallows about the house at Hastings.[135] In the same season flocks of Martins were hawking vigorously, in the vicinity of Penzance, to the 28th of November, as witnessed by Mr E. H. Rodd.[136] Captain Hadfield again, writing in 1856, gives extracts from his journals, whereby he records having seen Swallows and Martins as late as November 3, 1841, December 2, 1842, November 13, 1852, November 22, 1853, November (about the middle) 1854, and November 24 (Swallows) and December 2 (Martins) 1855.

Of the last-mentioned occurrence he gives the following interesting note:--"Dec. 2, 4 P.M. Observed eight Martins flying round the garden, and occasionally alighting on the perpendicular face of the wall of a house near my garden gate, to which they would cling for a few seconds, and then, dropping off, whirl round, returning to the same spot, seemingly quite unconscious of my presence and that of several others: they seemed bent on effecting an entrance under the eaves of the house, by a small opening they had discovered near a water-pipe that had been carried through the wall: they were, I believe, all young birds of the season, as they appeared small, their tails being also shorter than in the adults; they were weak on the wing, but that may have arisen from their being benumbed by the cold, the thermometer standing at 44 only at the above hour. There had been a bright sun during the greater part of the day, but I had observed a white frost in the morning. I conclude that these late birds were merely seeking a roosting-place for the night, and not a place of concealment for the winter, although I might have been excused, according to Cuvier, White, &c., had I thought they were taking up their winter quarters; but I have not sufficient faith in the theory to induce me to unslate a part of the roof to seek for them, which might be done, however, at a trifling cost, provided permission were obtained."[137]

It is rather a pity that the observer had not confidence enough to induce him to make the investigation which he suggests.

Mr William Bree mentions as many as fifteen or twenty Martins and Swallows sporting in the air near Temple Balsall on the 18th November 1846, adding that he has frequently seen individuals much later, but never recollects to have seen so great a number together at that late period. And, finally, Mr J. Johnston, jun., reports that he saw, in the afternoon of 18th January 1837, three Swallows dipping and hawking as in summer, near Wakefield.[138]

There is less evidence of the appearance of these birds before the ordinary time of arrival of the migrants. But White, when a boy, observed a Swallow for a whole day together on a sunny warm Shrove Tuesday, which day could not fall out later than the middle of March, and often happened early in February.[139] And Mr Samuel Gurney, jun., together with several other persons, saw either a Martin or Swallow, on the 27th of March 1844.[140]

If this last occurrence had stood alone, it would have been of slight importance; for Yarrell mentions a single Swallow as having been seen by a fisherman near the Eddystone as early as the 4th of April; and Sand-martins, even as far north as Carlisle, before the end of March. It is just possible that these may have been stragglers of the great army of migrants, arriving some ten or fifteen days before their time; but considering the whole great array of evidence, I rather believe that these too were hybernants, who had been prematurely awakened from torpidity by unusually warm days.

The accounts of _Hirundines_ having been found in a somnolent state in winter may or may not be true; though the great number of such statements in various and distant countries makes the indiscriminate rejection of them even more difficult than the acceptance. But still there remains the undeniable fact that it is quite an ordinary thing for birds of this family, including all our four common species, to be seen with us through November and December, and occasionally in January;--that is, for two or three months after the great body of migrants have left the country. No one, I suppose, pretends that migration of Swallows takes place in December or January; therefore it is manifest that a certain number--more or fewer--remain. What becomes of them? We certainly see them only occasionally: where are they on the days on which they do not appear,--days extending to several consecutive weeks? If they had not been torpid during those weeks, if the more active functions of life had not been suspended, would they not certainly have been starved? But the specimen shot on the 10th December, and examined by Mr Bell, was in good condition, which is consistent with but one alternative; either it had been well fed throughout the preceding six weeks, or it had been hybernating. But the former supposition implies that it had been habitually on the wing during that period, as Swallows feed only on the wing; which could not have been the case without its being noticed and recorded.

It is common to say that these occasional winter Swallows are the later broods of young, which, being too infantile to migrate, are compelled to linger in the country of their nativity, and becoming lethargic from the advancing cold, at length die before the spring. But when this hypothesis is looked at, it seems hardly tenable. In many of the instances recorded, the specimens seen even late into the winter, are represented as gaily and vigorously hawking for flies, or sweeping over the water as in summer. This does not look like poor deserted orphans starved with the cold, retiring to die; but birds in health, temporarily awakened from normal slumber by an unusual temperature, and instantly ready for a full use of their faculties. However, to settle the point by fact, Mr Bell distinctly states that his specimen of December 10th was "an adult bird, _not_ a young bird of the season."

If it should be asked why they do not appear in January or February, as well as November and December, the answer is obvious. The winter's lethargy of hybernating warm-blooded vertebrates is much more readily interrupted in the earlier part of the season than in the middle and latter part. And this is natural; for the more intense cold of January benumbs and suspends the vital functions far more completely, and the _coma_ so superinduced is sufficiently deep to resist the counteracting influence of a few warm days, even though the temperature should be as high as on those earlier days that awakened them, or even higher.

The aggregate evidence, then, seems to leave no room for reasonable doubt, that a certain number of our _Hirundinidae_,--few, indeed, as compared with the vast migrant population, but still considerable, looked at _per se_,--for some reason or other, evade the task of a southward flight, and remain, becoming torpid, occasionally betrayed into a temporary activity, and resuming their active life, about the same time, or occasionally a little _before_ the time, of the arrival of their congeners from abroad. It is, however, desirable for the absolute settlement of the question, that specimens, actually discovered in a lethargic condition, should come under the observation of competent scientific naturalists, _open to conviction_, who would leave them _in situ_, keeping an eye on them from time to time till the return of warm weather in spring. It is not enough to take them into a warm room, and to shew that they revive in such circ.u.mstances: we want to know positively whether they will be resuscitated normally and naturally by the vernal warmth, and come forth spontaneously to sport, and wheel, and skim, and soar, and stoop, and hawk, and twitter,--among their travelled fellows. Who will undertake to decide the point in this manner? He will have achieved a name in science.

[113] _Phys. Theol._, vii., Note _d_.

[114] _Regne Anim._, (Griffith's Ed.,) vii. 61.

[115] _Phil. Trans._, 1763.

[116] _Letter_ x.

[117] Stanley's _Fam. Hist. of Birds_, p. 263.

[118] _Edin. Journ._, viii.

[119] In Pennant's _Brit. Zool._

[120] _Brit. Zool._, App.

[121] _Zool._, 1136.

[122] Ibid., 2302.

[123] _Zool._, 2590.

[124] _Letter_ x.x.xviii.

[125] Ibid. xii.

[126] Ibid. xi.

[127] Ibid. x.x.xi.

[128] _Letter_ xxiii.

[129] _Orn. Dict._, Introd., xxvii.

[130] _Zool._, 5364.

[131] _Brit. Birds_, ii. 264.

[132] _Zool._, 2455.

[133] Ibid., 565.

[134] Ibid., 3753.

[135] _Zool._, 4945.

[136] Ibid., 4945.

[137] _Zool._, 4995.

[138] Ibid. 1639.

[139] _Letter_ xviii., 2d ser.

[140] _Zool._, 565.

VI.

THE CRESTED AND WATTLED SNAKE.

About the middle of the last century there existed in Amsterdam a Museum of natural history, which, though acc.u.mulated by the zeal and industry of a private individual, far exceeded in extent and magnificence any collection then in the world. It had been gathered by Albert Seba, a wealthy apothecary in the Dutch East India Company's service, who fortunately published an elaborate description of its contents. This great work, "_Locupletissimi Rerum Naturalium Thesauri accurata Descriptio_,"--in four volumes folio, published from 1734 to 1765,--is even now remarkable for the accuracy and beauty of its copious engravings, which still are referred to as authorities, though the descriptions are devoid of scientific value. Many of these figures and descriptions, about whose reality no shadow of doubt exists, are those of creatures which are altogether unknown to modern science, and some of them are highly curious.

Serpents seem to have been a special hobby of Seba's; and he has delineated a vast number of species. Among them are two[141] about which a singular interest hangs. They are of rather small size; the one pale yellow, marked with oval reddish spots, the other reddish, with five green transverse bands. The head in each case has a h.o.r.n.y-pointed muzzle, and the cheeks are furnished with depending wattles of a coral-red hue.

From the expressions of wonder with which Seba introduces his descriptions of these animals, it is evident that they were no ordinary forms. He does not know whether to call them Eels or Serpents, the critical characters, which in our day would instantly determine this point, being then scarcely heeded. He calls them "marine," but whether on any other evidence than the pendent processes of the cheeks, which he calls "fins," does not appear. But no fish known to naturalists will answer to these representations. The pointed head, indeed, resembles in some respects that of _Mur{oe}na_, but this genus of fishes is altogether dest.i.tute of pectoral fins, while the vertically-flattened tail, and the long dorsal and a.n.a.l fins confluent around the extremity of the body in _Mur{oe}na_, are totally unlike these figures. These and all similar fishes are, moreover, dest.i.tute of visible scales; but in these the scaling is decidedly serpentine, and the second, in particular, has large symmetrical plates across the belly, while the head in both is shielded with broad plates like a Colubrine Snake. The tail is drawn out to a long conical point, without the slightest appearance of compression or of bordering fins. In one figure there is seen a little projecting point at the edge of the lower belly, which at first sight suggests the idea of the a.n.a.l hook of a _Boa_, but which, by comparison with other figures, we discover to be intended to represent the projection of the pre-a.n.a.l scale. The very minuteness of this character makes it valuable: its value was doubtless unheeded by the artist, who merely drew what he saw; it is, however, a very decisive mark of distinction between a serpent and a fish.