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."