The Grey Wagtail has been repeatedly observed to indulge in a fancy which might well obtain for it the name of 'window-bird'. The first recorded instance occurs in an early number of the _Zoologist_, where it is stated, that every morning for a period of between three and four months, from the beginning of October to the end of January, a Grey Wagtail came to the window of a country house as soon as the blinds were drawn up, and darted against the panes of glass, pecking with its beak as if it saw some object. It would then retire, and after a pause repeat the operation, but from what motive no one could conjecture. A lady writes to me from Dewlish House, Dorsetshire: 'We are constantly being disturbed by a yellow-breasted Water-Wagtail, which comes tapping at the windows or skylights, from the first streak of light till evening. What may be his object no one can say. It is too cold at present (March) for flies or spiders, and, had there been any hybernating there he would have eaten them long ago, he comes so frequently. When, on going upstairs, or when sitting down in my room, I hear this loud repeated tapping, it is vain for me to open the window and try to entice him in with crumbs; he does not even notice them. This morning he woke me at about four o'clock. You would have said, 'Some one rapping at my window as a signal that I must get up. An old servant tells me, "Ah, 'twere just the same last spring, when the family were in London; they say that it do mean something."'
The Grey Wagtail does not commonly build its nest in the southern counties of England, although instances have occurred. It prefers hilly and rocky districts. More frequently it repairs in spring to the north of England and south of Scotland, and builds its nest on the ground, or in the hole of a bank, or between large stones, and never at any great distance from the water. It is composed of stems and blades of grass, mixed with moss and wool, and lined with wool, hair and feathers.
THE BLUE-HEADED (OR GREY-HEADED) WAGTAIL MOTACILLA FLAVA
Top of the head, lore, and nape lead-grey; over the eye a white streak; scapulars, back, and upper tail-coverts greenish olive, tinged with yellow; chin white, in the young male yellow; under parts bright yellow. Length six inches and a half. Eggs mottled with yellow, brown, and grey.