It is also important to note, that while so abundant at the outlying station of Isle of May and Bell Rock on the E. coast, there should have been an almost complete absence of any of these species at the next station, a little higher up the Firth of Forth, viz., at Inch Keith; and to record that it appears to be always with westerly winds that birds occur there. While there were hundreds of records at Isle of May, there were none with the same winds at Inch Keith, and only about ten records in all. Its somewhat landlocked position accounts for this, and its being sheltered from the S.E. winds places it on a similar footing with Chanonry and Cromarty, in the Moray Firth. Weather.—Upon our E. coasts, easterly and south-easterly winds prevailed throughout the greater part of the migratory seasons, both in spring and autumn, and reached forces of from fresh to gales. On the W. coast the wind was for the most part westerly and north westerly, rarely S. during spring, at the greater part of the stations, and was easterly and south-easterly in autumn, seldom reaching fresh or strong, or gales, as on the E. coast, usually light, or from light E. or S.E. to variable. The above facts will be considered, whilst we state next the distribution of the migratory waves on the W. coast, in relation to those on the E. coast. As in 1881, records on the W. coast begin to bulk more largely towards the southern stations. All north of Rhinns of Islay and MacArthur's Head the records of land-birds are very scanty, and the lighthouse keepers remark upon the scarcity. At usually (normally) crowded stations, such as Skervuile, they are reported as yielding "fewer birds than for many years back." Even at Rhinns of Islay the records are not large, but they begin to show an increase at this point. Unfortunately I have no autumn returns between Rhinns of Islay and Corsewall, which latter is south of the Firth of Clyde.
Now, if anything additional to the general bulk of the records is required to show the line of migration of 1882, it is the significant record of the Golden-crested Wren at Rhinns of Islay on Oct. 10th, and at Corsewall and stations to the south, but nowhere to the north of the former station. Now, it seems that the strong easterly to S.E. gales on our E. coast, which brought over such streams (rather than rushes) of birds,—such countless thousands,—did not carry them forward across the breadth of Scotland to any appreciable extent, but that the birds, tired and storm-tossed, rapidly sought rest and shelter on arrival; and that we have only on the W. coast indications that such a great stream broke upon the E. coast. These indications, however, are strong enough to enable us to mark out, with some degree of certainty, the lines and turning-points of the stream.
If we do this, by comparing the records of the various schedules, we find that, south of the Firth of Clyde, the records bulk most largely; and we also find that the dates agree with those of the E. coast.
MacArthur's Head and Rhinns of Islay appear to me, from the bulking of records, similarity of dates, continuance of light E. winds, and species occurring, to represent the turning-point of the autumn migration from E. to W. Rhinns of Islay is a salient angle, catching glimpses of passing birds from N.W. to S.E. Otherwise, if the strong gales did not cause all birds to drop for shelter on Scotland, it must have carried many far out over the Atlantic, as in 1880. Isle of May sends in 19 schedules, and Pentland Skerries 8. Bell Rock sends 2—thickly filled—and North Ronaldshay 3, but bulking less than Bell Rock. What has become of the many birds passing through the Pentland Firth? We find little indication of them at the nine northerly W. coast stations. Have many overshot the land and passed out over the Atlantic?
Another point worth noting, is the occurrence of many birds in spring at the same stations frequented by the species in autumn. Thus, at Mull of Galloway on March 8th and 9th, with westerly winds. Goldcrests were abundant, and at the same station on Oct. 15th and 16th, an autumn-rush took place, with easterly and N.E. wind and haze. The same double records occur at Bell Rock and Isle of May as regards many species, and especially Turdidæ and Regulus cristatus. This "returning" upon old lines has already been remarked upon by my colleague, Mr. J. Cordeaux, in our Third Report (p. 38). Since these last sentences were written, I have received the first of the 1883 schedules from the Isle of May, and may here state what the effects of the succession of N.E. gales in March have been on the spring migration, leaving however the details of Mr. Agnew's schedules to be worked into our next—1883—Report. I give this in Mr. Agnew's own words, as I entirely coincide with the opinions expressed. Mr. Agnew writes on the back of the schedule as follows:—"With reference to your note on the schedules sent, as to the effect of the N.E. gale of March 6th, 7th, and 8th, 1883, you will see from the entries inside that the effect of that gale was almost to stop migration at the Isle of May. Migration that had set in pretty briskly on the 2nd almost ceased on the 5th, and from that date we had only a few stragglers of the strongest wings, up to the 19th. I believe the effect of that gale was to drive the birds that should have come this way, away to the southward. Had the gale been from the S.E. it would have been different here."
In fact, a N.E. wind reaching such strengths as those of March 1883 did, acts very much in the same way upon spring migrants, pressing them more to the southward, as north-westerly strong winds and gales act upon the autumn migrants, whose normal course is from E. to W., or S. of E. to N. of W. It will be interesting to trace this further from the schedules returned from other stations, when they come in for 1883. Another point to note in spring migration of 1883, will be the greater westering of the return migrants, if we may use the expression, partly consequent upon the greater westering of the autumn migrants, caused by the long-continued and strong south-easterly winds of the preceding autumn, and partly upon the north-easterly winds of March pressing them down and deflecting their course to more inland and sheltered lines.
In this connection I would speak here of the great assembly of the Pied Wagtails on the narrow stone horizontal moulding above the upper windows of the General Post Office, Edinburgh, where, upon March 17th, 1883, A. B. H., who recorded the facts in the 'Scotsman' of that date, counted more than sixty; and he adds, in a subsequent letter to me, "there was at least one in every niche of the carved capitols of the columns. I think I am quite within the mark when I say there were 150 birds altogether." This flock roosted there on March 17th and 18th, but disappeared on the 19th, owing, Mr. H. thinks, to a rise of temperature and the wind going round from N.E. to S.E. Mr. H. was informed that numbers, probably the same birds, were seen feeding at Duddingstone Loch on the 18th. Now, several years ago, a similar assemblage was noted at the same locality, by a well-known Edinburgh ornithologist, but it occurred, not in spring but in autumn, and a general movement was at that time also noted by Mr. H., and recorded in the Proc. Ryl. Phyl. Soc. of Edinburgh, on Jan. 15th, 1879, from which last noted records of autumnal migration it would appear that he saw about seventy Pied Wagtails on the roof a house in Edinburgh, in the middle of September, 1878, and Mr. Scot Skirving, of Edinburgh, on a previous occasion, saw some 300 at the General Post Office, but the exact date of this latter record has unfortunately been lost or mislaid, as we are unable, of course, to find out definitely the meteorological phenomena accompanying the record.
Further, my friend Mr. Eagle Clarke, notes the arrival of the same species in the neighbourhood of the Ure River, near Masham, Yorkshire, as early as Feb. 5th, 1883. Though resident in the lowlands about Leeds, it is migratory to and from the higher lands. Mr. Eagle Clarke has often seen as many as 200 in a flock, on a large lawn near Leeds.
Mr. Agnew informs me, that with a S. wind there is little migration past the Isle of May, and that S.E. is the best wind in spring to permit of observations being made. Five Wagtails were seen at Isle of May on the 29th and 30th, however, during a gale from the S.
The Spring Migration of 1883 seems to me to indicate the direct effects of the N.E. gale, causing these Wagtails to keep inland by a more sheltered route, which Wagtails in ordinary weather would probably have passed up the coast-line and crossed the entrance of the Firth of Forth, showing themselves at Isle of May and Bell Rock stations. Mr. Robert Gray has, I believe, frequently observed the spring arrivals of this species on the west coast—in Ayrshire; and it will be interesting to see if we can trace the movement up the west coast, on the returning lines, when schedules are returned for 1883, from Mull of Galloway and other west coast stations.