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 its numbers increase, until in parts of Scotland, 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.