Closely resembling the last-named in form and general appearance, the White Wagtail long escaped observation as an annual summer migrant to this country. Its distinctive characters, however, are now almost universally admitted, and ornithologists experience little difficulty in recognizing the two species. The particular respects in which the White Wagtail differs from its congeners are noticeable chiefly in the summer, or breeding plumage, when the former has a black cap clearly defined against a grey back, while in the latter the black colour of the head merges in the black of the dorsal plumage and no such cap is discernible. In summer both species have the chin black, and in winter the same parts in both are white. In the immature and winter dress it is not so easy to distinguish them, and in form and structure at all ages and seasons no real difference seems to exist. This has naturally raised some doubt in the minds of many as to the validity of the so-called species, a doubt which is strengthened by the circumstance that in regard to haunts and habits the two may be said to be inseparable. This much, however, seems to be certain, that whereas the Pied Wagtail is generally distributed as a resident species, migrating southward at the approach of winter, the White Wagtail spends only the summer months in this country, and is then very local in its distribution. Beyond the British Islands the White Wagtail has a much more extensive range than its congeners, being found throughout the whole of Europe, penetrating to the North Cape and even to Iceland, and travelling southward beyond the Mediterranean into Africa, to within a few degrees of the equator. [Illustration: GREY WAGTAIL] THE GREY WAGTAIL. (_Motacilla sulphurea._) Except 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.