With such favourable passages as light head winds afford, our immigrants are so little fatigued that they will not alight on reaching land, but keep on their course into the interior. I have watched for hours flock after flock arriving on the east coast, coming directly from westward, Rooks, Starlings, Lapwings, and Snow Buntings, and keeping on in a direct westerly direction as far as the eye or a good glass were able to follow. Often, too, when on the hills, miles from the sea, I have seen migrating flocks passing inland. Larks in straggling flocks, carrolling cheerily as they pass; there is no bird which migrates so cheerily and light-heartedly as the Lark, ever ready to burst into song on the least occasion. At other times, with adverse winds, I have watched migrants scarce able to struggle on shore dropping in the first shelter, or even on the bare wind-swept coast. At Lynn Well light-vessel large numbers of migrants passed day by day, and for the entire day, during October, from S.E. or S.S.E., and even S. to N.W. From the position of this station off Lynn Deeps at the bottom of the Wash, under the shelter of the north-westerly trend of the coast, these migrants must have first crossed the northern part of the county of Norfolk, without alighting, on their way to the fens of Lincolnshire and Cambridge, and this both by day and night.
"Yet stoop not, weary, to the welcome land,
Though the dark night is near."
It is very remarkable how suddenly the stream of migration commences running, and how suddenly it stops again. We watch, at early morning, a flock of Larks or Hooded Crows come to land; others soon follow, and then for some hours—it may be from 8 a.m. to 1 p.m.—there is a constant arrival of migrants; and then migration, at least for that day, is over, and not a single wanderer will be seen.
As a rule, the young of the year migrate some weeks in advance of the old birds; this holds good with all orders and species. In the spring the males often migrate in advance of the females.
The time of migration of any particular species extends over a considerable period; sometimes it is over in four or five weeks, in other cases going on for months, and even half a year; for, practically, such birds as the Lark and Starling are migrating all the year round. In every case the migration of a set species will continue, day by day, or week by week, till it attains the maximum by a "great rush," the main body passing, and then gradually falling off, till the migration of that species is completed.
Independent of the normal or ordinary migration, we have frequently local migrations, due to sudden changes of weather, or in search of fresh feeding-grounds. These "great rushes" of immigrants, coming helter-skelter on to our east coast, are often accompanied or followed very closely by outbursts of severe weather; and a sudden increase of cold in winter will almost clear a whole district of its birds; in fact, all birds are very susceptible to changes of weather, and, if closely watched, will indicate by their movements the coming change. On Jan. 12th, in this year, when in the Humber marshes, I noticed Larks and Snow Buntings passing from N. to S. from 9 a.m. to 2 p.m., separate flocks for some hours, and after 11 p.m., when the snow commenced, continuous.
Birds in the early autumn do not, it is evident, migrate for lack of food, for the young of the Limicolæ are on our coast at a time when the supply of insect-food in high northern latitudes is the most abundant; and our own insect-eating birds are often away long before there is, or can be, any falling off in food. On the same grounds it is not changes in the seasons which can induce young birds, having no knowledge from experience, to return south in the heat of the Arctic latter-summer; as to the how and the why of the whole matter, we must be content for the present to say nothing, but continue to collect facts.
In 1880 the main body of the migrants crossed between the 15th and end of October, the greater number perhaps on the 17th of that month.