The mortality amongst these autumn migrants can scarcely be over-estimated. Young birds of course predominate in every species, and it is among them that the death-rate is highest. Gales and dark nights, with driving rain or fog, are exceptionally fatal to these journeying birds across the German Ocean. Some of the scenes at the lighthouses and light-ships along the coasts of these northern shires are most impressive on such nights as these. The lost bewildered birds, attracted by the glare of the flashing brilliant lamps, crowd round the lanterns, and many of them not only kill themselves by dashing against the glass but are observed to fall exhausted into the sea below. Birds of many species compose these lost and bewildered flocks. Adversity makes strange companions, as the old saying has it, and never perhaps was it better illustrated than by a crowd of birds at the lantern of a lighthouse. Significantly enough, the return passage in spring is invariably undertaken by numbers scarcely a tithe as great as in autumn--the bulk of the little pilgrims having met their fate either on passage or during the intervening winter.
In the northern shires birds of some species or another are almost constantly moving about throughout the winter months. Even in inland localities this fact is abundantly apparent to the most casual observer of birds. Rough weather and snow-storms are almost invariably accompanied or heralded by wandering flocks of Lapwings and Larks; Finches and Fieldfares are constantly moving about as the food supply becomes exhausted or inaccessible in various districts; Ducks and other water-fowl change their haunts as frost compels them. We might also here allude to the considerable amount of vertical migration that takes place in the northern shires--that movement between the uplands and the low-lying country and littoral districts, undertaken by such species as Twites, Merlins, Meadow Pipits, Lapwings, Plovers, Curlews, Mallards, and some few other Ducks. This movement has already been described in detail in our accounts of these various species, so it is not necessary to treat with it here at greater length. It is, however, a migrational movement of no small interest, though not a little overlooked by ordinary observers. Thus does the migration of birds progress, in spring and in autumn, across these northern shires, the phenomenon being very similar in its general aspects from year to year. Variety is, however, furnished in the numbers of the several species that so migrate, in the dates of their movements, and also in the occurrences of those abnormal migrants for which these shires have an exceptionally abundant share. We have not space here to chronicle the species that have paid these shires such abnormal visits, but the subject is certainly an interesting one and worthy of passing mention at least.