When the nest has to be constructed—and it is always upon the ground—more sheltered spots are selected, such as a tussock of rough grass, or the foot of a bunch of tares or clover, and I have occasionally discovered a nest under an overhanging clod upon a bare fallow. Thus in regard to its mode of nesting it differs essentially from the well-known Pied Wagtail. Its note, too, is very different, and its flight much sharper, and with bolder curves. The eggs are quite dissimilar, being so closely freckled over with yellowish-clay colour, like those of the Grey Wagtail, as to appear at a little distance almost uniformly so coloured; whereas the eggs of the Pied and White Wagtails are white, freckled with ash-grey, chiefly at the larger end. The Yellow Wagtail generally arrives in this country during the first week of April (for many years I have noted the 5th of that month as the average date for its appearance), and it departs during the first week of September. For some time previous to its departure, the young and old assemble in flocks, and it is not unusual to see several united family parties in the meadows, numbering from a dozen to a score of individuals. Although generally distributed during the summer months throughout the greater part of England and Scotland, it is said to be somewhat rare in Ireland, where its presence has been detected by comparatively few observers. So much more attention, however, is paid to ornithology now-a-days, that this species, like many others, may be reported to be more common than formerly because more observed. In the central and southern portions of Europe it is not uncommon, and crossing the Mediterranean, as winter approaches, it passes down both the east and west coasts of Africa as far as Natal on the one side and Angola on the other. A considerable number, however, pass the winter in Africa, a good many degrees further north. THE GREY-HEADED WAGTAIL. (_Motacilla flava._) Similar in form and general colouration to the last-named, amongst the flocks of Yellow Wagtails that visit us in the spring the grey-headed species no doubt often escapes observation. But it is not on this account to be considered rare. On the contrary, there is good reason to believe that it is a regular migrant to this country, and this is not surprising when we consider that it is the common Yellow Wagtail of northern Europe, the true _Motacilla flava_ of Linnæus. It differs chiefly from Ray’s Wagtail in having a well-defined cap of a grey colour on the head, a white instead of a yellow streak over the eye, and a white chin instead of a yellow one.[37] It frequents the same situations as the last-named, and its habits are very similar.