The haunts of the Grey Wagtail are somewhat different to those of its congeners. It affects pools and streams, especially where there is a good current, and may frequently be seen perched upon boulders and mill-dams, where it feeds upon the freshwater limpets (Ancylus fluviatilis), and other small mollusca which are found attached in such situations.
The nest is generally placed not far from the water, in some inequality of the bank, or crevice of an overhanging rock. Upon a rugged mountain stream in Northumberland some years since, I daily observed a pair of these birds, and derived much pleasure in watching their building operations. It was some time before I could discover the nest, so skilfully was it concealed, for the birds had selected a crevice in a rock which was much overgrown with moss, and by constructing their nest entirely of this moss, it would easily have escaped observation, had I not patiently watched for the ingress and egress of the owners.
The geographical range of the Grey Wagtail beyond the British Islands has not been satisfactorily determined, in consequence of the difficulty of identifying the species amongst other allied forms which are to be met with in the confines of Europe and Asia. It certainly does not go far north in Europe, perhaps not beyond Northern Germany, but southward it is met with in winter in most of the countries bordering the Mediterranean, as well as in North Africa, Madeira, and the Azores.
THE YELLOW WAGTAIL.
(Motacilla Rayi.)
By many authors the Yellow Wagtails have been separated from the Pied Wagtails under the generic term Budytes, proposed by Cuvier, not only in consequence of their very different colouration, but also on account of their possessing a longer and more strongly-developed hind claw. The numerous intermediate forms, however, which the researches of modern naturalists have brought to light from various parts of the Old World, have rendered this subdivision less necessary or desirable than it may originally have appeared to be. In outward form, internal structure, and habits, they are all Wagtails, and one generic term for the whole has, at all events, the merit of simplicity.
The Yellow Wagtail, whose plumage in the breeding season equals in brightness that of the Canary, is one of the most attractive of all our summer migrants. When running over the pastures and fields of sprouting wheat, the olive-green colour of the dorsal plumage renders it very inconspicuous, but when perched upon some rail, or clod upon the bare fallow, the bright yellow of the under-parts contrasts vividly with the duller surroundings, and at once attracts the attention of the passer-by. Its favourite haunts are the marshes and water-meadows where cattle are pastured. Here it finds plenty of food amongst the insects which are disturbed by the grazing kine, and the numerous small and thin-shelled mollusca which abound in such situations.
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.