GENERAL REMARKS.
Our thanks are again due to the numerous Reporters, whose names are given under the "Diaries" of the two coasts.
Additions to our List of Stations are Fidra in the Firth of Forth, and also very shortly after this will be added a light-vessel off the Carr Rock, coast of Fife, holding an intermediate position between Bell Rock and Isle of May; and on the west coast the light upon Ailsa Craig. It is intended to introduce the electric light at Isle of May, and machinery and works are at present in course of erection.
We regret to learn that an order has been issued that lighthouse keepers shall no longer be allowed to read or write in the lantern-rooms; and we are glad that some little notice has been taken of the fact in the House of Commons on the 12th April 1886.
The 1885 schedules show distinctly the compressed nature of the migration, which, while very considerable in numerical importance, was, at the same time, short, sharp, and decisive. The principal spring rush was similar, occupying only a few days at the comparatively late date of the beginning of May, particulars of which can be gleaned directly from the Diaries of the stations, and especially under Turdidæ, Fieldfares being unusually plentiful. This appears to have been the heaviest movement, taking all species together, but Saxicolinæ travelled all April and May, and Silviinæ about the middle of April.
Shortly, we may describe the migration of 1885 thus:—
In spring of 1885 the rush was pronounced, somewhat late, compressed, and in many respects very similar, but not so extensive as 1884. The prevailing winds were easterly and southeasterly in April and May, and had been very continuous. The effect was the compression spoken of—a closed fan. The largest migration ever witnessed at the Isle of May was on 3d May 1885.
In autumn the rushes partook of a similar nature,—short, sharp, and decisive, but very considerable in numerical importance. Previous to middle of October, migration was very slight at any stations, but great rushes took place between then and about the middle of November. An interesting note of the cross-migration of Woodcocks, and other birds, is given at the Isle of May. Woodcocks travelling towards the N.W., and striking the S.E. side of the glass, whilst other species were flying S.E., and striking on exactly the opposite side of the lantern, both flights being equally favourable, or nearly so, by the light E. wind. Another N.W. to S.E. rush took place during the day-time, of what must have been a very extensive migration, upon the 10th November; wind light south, and birds flying high. An unprecedentedly high gale as coming from the S.E. is recorded at Isle of May on the 23d.
We would like to ask our readers, and the British Association, of which we are a Committee, to recognise that the more we know about migration, apparently the less reason is there for scientists to use the term "Accidental." At present "Abnormal" is better. "Of accidental occurrence" is a term or phrase which ought to be expunged, root and branch, from scientific records of migration. Every year's statistics prove this more and more fully. "Probably an escape" is, no doubt, a safeguard against undue admission to the British List; but we think it possible to carry this phrase too commonly into use, ignoring the fact that migration may account much more simply for such occurrences, under certain conditions, than escapes. A list of localities where foreign fowls, like Porphyrio melanotus, are kept throughout the United Kingdom, would greatly facilitate positive records of "occurrences;" and all such species as Canada Geese and ornamental Waterfowl, which are kept in confinement or partial domestication, might be returned to the Committee, or to the Association, by the proprietors, if they were asked to do so by circular.
From every succeeding year's statistics, we have come almost to similar conclusions regarding the lines of flight. Three salient routes on to our East Coast of Scotland are invariably shown, viz.: (1st) viâ the entrance of the Firth of Forth, and as far north as Bell Rock, both coming in autumn and leaving in spring; (2d) viâ the Pentland Firth and Pentland Skerries, both in spring and autumn; and (3d) viâ the insular groups of Orkney and Shetland, which perhaps may be looked upon as part of No. 2; and a fourth with almost certainty passes into the Moray Firth, but avoids the high cliffs of the east coast of Aberdeenshire.
On the other hand, three great areas of coast-line, including both favourably placed and favourably lighted stations, almost invariably, save in occasionally protracted easterly winds, and even then but rarely, send in no returns or schedules of the very scantiest description. These areas are Berwickshire, the whole E. coast south of the Moray Firth, and Caithness and E. Sutherland. Each and all of these areas possess high and precipitous coast-lines, if we except the minor estuaries of the rivers of Tay and Dee, and a small portion of lower coast-line in Sutherland, which face towards the east. Nevertheless these areas partake to a very large extent of the numbers of migrants which visit Scotland. Nowhere in Scotland, perhaps, is summer bird-life more abundant than in, at least, the two more southern of these areas—Berwickshire, and the interior of Aberdeen and Banff, and the valley of Spey and its tributaries. The question appears a natural one: by what route do these summer visitants reach us? or, by what route do birds reach us in autumn? Not, I believe, over the high cliff edge in the latter case, otherwise some migration would certainly be visible from the rock-bound stations. As shown in one case, positive assurance is given by the reporter at Noss Head, that for eleven years scarcely a bird "had been observed on migration day or night," and we have scarcely any statistics to show a contrary view, as regards the said area all through our seven reports.
How, it is known with considerable certainty that Caithness owes its periodical passing visits of such species as Blackcap and Pied Flycatcher, both in spring and autumn, to its immediate proximity to one of the chief highways of migration—the Pentland Firth; and the configuration of the N.E. peninsula of that county clearly points to the route by which spring passing migrants reach the E. coast of the county, as we have already explained in previous remarks. They cross over a low-lying depression in the land from Dunnet Bay, and cut off the peninsula of Canisbay. Coming again in autumn, the same birds, to some slight extent, may return across this peninsula, but the undoubted fact remains that the compressed and strongest flights cross over the Pentland Skerries and through the Firth.
In the same way, it appears that while scarcely a bird is ever recorded at the stations along the E. cliff-edge of Aberdeen, yet, in autumn, a well-marked stream of migration enters the N.E. counties at a point westward of Troup Head, which forms the northern abutment of the dividing ridge, or watershed, between what are known as the Faunal areas of "Moray and Dee;" and that thence up the wide open valley of the Spey, and over the low-lying portions of the south coast of the Moray Firth, this stream is clearly traceable at many points. It is also known that an equally decided spring "return" descends the same great valley, and enters it across the dividing range between the head waters of Spey and Spean or Pattack. We have studied this subject locally—at many points personally—especially in spring, and notes we have taken, dating back for many years, all tend to strengthen the statement.
In the same way it appears almost equally certain, that while few birds fly across over the cliff-edges of Berwickshire, but pour in vast streams up the open and wide Firth of Forth, still Berwickshire, and the interior of the south of Scotland, are well supplied with migrants; and the "return" is equally apparent. A study of our previous remarks by our readers cannot, we think, fail to give them the idea of the process of the population of these interior portions of the country in Scotland.
England is differently circumstanced to a great extent, owing principally to its low-lying sea-board. There is no occasion there to have the great migration waves compressed into grooves and firths and depressions.
The further question naturally may be asked, "But why should they not fly in over the cliff tops?" We think there are already many reasons stated in our previous remarks why such is less likely to happen, during normal migration, whether by day or by night, and that they should avoid obstacles, and choose an easier if not a shorter route.
The population of these interior parts, which are bounded by precipitous coast-lines, appears to us almost certainly to arrive by the innumerable veins—if I may so call them—which run into and join the main arteries,—and thus a circular migration is evinced.
Birds in normal migration against a beam wind fly low, and on reaching low-lying sea-board pass on inland without resting. But on approaching high land, say 200 or 300 feet in height, while at night the greatest darkness is ahead of them, and the greatest light to the north or south of their course; during the day-time, if the wind is off-shore—a beam wind,—on approaching the lee shore, they enter upon a calm belt of sheltered air and water, and choose the easier path along shore. According to whether the off-shore wind is strong or light, will they approach nearer or keep further out; and, skirting the coast-line, so enter upon one of the great open highways of normal migration. This, which appears almost undoubted, will in great measure account for the invariably slender returns sent in by nearly all the rock-bound stations of the more precipitous portions of the Scottish Coast.
Regarding the migration of Woodcock generally, the following notes may prove of some interest. These I culled from the note-books and game register of a naval friend stationed at Corfu and the Albanian coast in 1879.
The first flight of Woodcock occurs about the first ten days of November, and it remains a very short time before passing on, unless abnormal "south winds keep them in cover." The second and heavy flight occurs about the middle of December, and may remain a mouth, and odd birds are shot even in February in the lower covers. Thomas Wood, Esq., British Consul at Patras,—an authority for the locality,—says that Woodcock come in November with a N.W. wind most freely, but in December with a N.E. wind.
By a study of the area over which the Woodcock breeds, of the time they take in flight, and of a comparison of the dates of arrivals at Heligoland and East British Coasts with the above,—it seems pretty clear, I think, that the early flight, which extends along the whole Albanian coast is composed entirely of birds bred amongst the higher levels of their southern range, coming probably from the Carpathians and as far south as the Balkans, as well as from high localities even nearer to the Albanian coast and coverts. It seems to us also equally clear that the December flight, preferring the beam wind from the N.E., comes from the western parts of North Europe, having originally started from the breeding areas of the extreme north. On starting, we will say, from the N. of Scandinavia, or Scandinavia, and other parts of the breeding range, they arrive on our coasts about October {our first flight). This corresponds with the first flight on the Albanian coast a month later. Birds reaching us congregate upon our islands under the genial influence of the Gulf Stream, but may finally be drawn off by December, and constitute a portion at least of the great flight at Corfu, where one ship's sportsmen have been known to kill something like 300 cock in a day or two (I have not the figures, but they are accessible, if necessary).
Regarding the subject of the arrival of young' birds in advance of the adults in autumn, the Committee, we think, should look at the movements exhibited by, and distinctly observable in, certain species. Those, perhaps, most easily observed are the larger Natatores, such as Geese and Swans and Gannets, whose distinct movements can be watched year after year, and recorded with almost absolute certainty. We do not intend to dilate upon the importance of this method at present, but in the connection will merely quote a significant passage from Mr Robert Gray's "Birds of the West of Scotland,"[1] and to supplement it by saying that there can be no doubt as to the accuracy of the observations made, as they are well known to the inhabitants. Mr Gray says: "Previous to leaving, the Barnacle Geese assemble in immense flocks on the open sands, at low tide, in the Sounds of Benbecula and S. Uist; and as soon as one detachment is on the wing, it is seen to be guided by a leader, who points the way with strong flight northwards, maintaining a noisy bearing until he gets the flock into the right course. After an hour's interval, he is seen returning with noisy gabble alone, southwards to the main body, and taking off another detachment as before, until the whole are gone. A notice of this singular habit was first communicated to me by Mr Alex. Carmichael, and has since been corroborated by Mr Norman M'Donald, who informs me that the inhabitants of the Long Island have been long familiar with it."
[1] Op. cit., pp. 349, 350.