Alca torda, Razorbill.—April 14th, St Tudwal's, hundreds of Puffins, Guillemots, and Razorbills arrived at sunrise. They left the island on August 14th. Longships, numerous from August 20th to October 28th.
Lomvia troile, Guillemot.—March 12th, St Tudwal's, 200 arrived at sunrise. Another arrival on April 14th. They left St Tudwal's on the 14th of August. Longships, observed from September 25th to October 29th.
Fratercula arctica, Puffin.—April 14th, St Tudwal's, hundreds arrived at sunrise along with Guillemots and Razorbills, leaving on August 14th. July 4th, Menai, Puffins at 5 A.M. Longships, observed going S.W. between August 14th and October 26th.
General Remarks.
The Report for the West Coast of England and Wales, and the Isle of Man, refers to the movements during the spring and autumn migrations of about one hundred species.
The spring immigration commenced on the 25th of March with the advent of the Swallow at the Bahama Bank light-vessel, and continued until the 15th of May, when "very many" Swallows appeared between 4 P.M. and 7 P.M. at Langness. A noteworthy incident of the vernal immigration was the great rush of Wheatears observed at the Bahama Bank vessel and at Langness on the night of the 13th of April, when many perished or were captured.
The spring emigration did not escape attention, for on the night of the 20th of April the returning Fieldfares, Goldcrests, etc., were observed at 11 P.M. at the Chickens Rock. Perhaps the continuous movements of Thrushes and Blackbirds observed throughout February, and especially between the 11th and 17th, are referable to this class of migrants.
The autumn emigration, so far as our summer visitants are concerned, may be said to have been initiated with the appearance of the Cuckoo at Langness on the 25th of July, and was prolonged until the 25th of October, when the last Swallow was noted.
The first immigrant winter visitant from Northern Europe was the Redwing, whose appearance at Carlisle was noted on the 20th of September. The chief general movements which usually characterise the southward autumnal passage were two in number, and affected the stations along the entire coast from the Isle of Man and the Eddystone. The first commenced on the 16th of October, and continued until the 20th. The second extended from the 8th to the 12th of November.
In connection with these general movements, which are so often—indeed, we might say usually—participated in by a great variety of species of very different orders seemingly seized by a simultaneous migratory impulse, it would be, perhaps, well to consult the meteorological record for an explanation of the phenomenon. Mr J. A. Allen tells us that "birds discern approaching meteorological changes," and that in the monthly weather reports of the United States Signal Service Bureau reference is often made to the movements of birds. "From these reports it appears that the southward migration of Geese and other Waterfowl usually precedes, often only by a few hours, the approach of heavy storms, and a sudden and very great reduction of temperature, which they often wholly avoid by keeping in advance of the change." It would seem probable, too, that birds await the approach of favourable meteorological conditions, and then, having been detained by unfavourable conditions, migrate en masse. Deeming that it would be interesting in connection with the great movements during the autumn of 1885, an examination of the weather reports issued by the Meteorological Office has been made. The first of these, as we have seen, commenced on the night of the 16th of October, and continued until the night of the 20th. "The [weekly] Summary of Changes in the Weather over the British Islands and their Neighbourhood[17] from the 11th to the 17th of October informs us that throughout this week the pressure over our islands and their neighbourhood has been mainly cyclonic; from the 11th to the 14th the type of gradient was northerly, but on the 15th and 16th it was easterly. Two well-marked depressions appeared in addition to the one which was passing away from us on the morning of the 11th. The second of these depressions, which had become a shallow subsidiary disturbance on the 15th over the south of France, moved westward from our area during the 16th; and as this system passed away, an anti-cyclonic "col" was formed over our islands, uniting an anti-cyclone over France with another off our extreme western coasts. With this anti-cyclone the cold northerly winds which had prevailed changed, and on the 16th the weather became very fine over England, the temperature rose, and the wind became a southeasterly breeze. The summary for the 18th to the 24th of October informs us that "the distribution of pressure over our islands and France was anti-cyclonic, with light or moderate south-easterly and easterly winds, till the 20th, then cyclonic and complex, with northerly winds."