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THE GREY WAGTAIL.
I 7* XCEPT for the purpose of a momentary -"—comparison, it would be beyond the scope of the present volume to notice the Grey Wagtail here, for this bird does not come under the definition of a Summer Migrant.
It is rather a winter visitant, being most frequently observed in the cold season, although many pairs remain in suitable localities throughout the country to nest and rear their young. Upon this point Professor Newton has remarked that "a line drawn across England from the Start Point, slightly curving round the Derbyshire hills, and ending at the mouth of the Tees, will, it is believed, mark off the habitual breeding-range of this species in the United Kingdom; for southward and eastward of such a line it never, or only occasionally breeds, while to the westward and northward its nest may be looked for in any place suited to its predilections, as above described, whether in this island or in Ireland, where, according to Thompson, it is extensively, though not universally distributed. In Scotland, says Macgillivray, it is rare to the north of Inverness, but it is an occasional summer visitor to Orkney, and in Shetland it occurs towards the end of summer, though it is not known to have been met with in the Outer Hebrides. In the south-west of England its numbers are in summer comparatively small, but it breeds annually in Cornwall and on Dartmoor; and as we pass northward
perhaps, they attain their maximum. Nests have been reported from Dorset, Wilts, Hampshire, Sussex, and even Kent; but in those counties they are confessedly casual, and only in the case at Chenies, in Buckinghamshire, mentioned by Mr. Gould (" Contr. Orn." 1849, p. 137), does the species seem to have been more than an accidental settler."
The Grey Wagtail may be at once distinguished by having the vent and upper tail coverts of a sulphur-yellow, and by its great length of tail. In summer it has a black patch upon the throat, of a triangular shape when viewed in profile, and bordered with white, but in winter this black patch disappears, and the throat is then of a pale yellowish-white.
It has been stated by Temminck and other naturalists who have followed him, that the black throat is the peculiar attribute of the male bird in the summer or breeding plumage; but this is a mistake. Both sexes have a black throat in the breeding season, as I know from having observed them when paired, and from having examined numerous specimens of which the sex had been carefully ascertained by dissection.
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.