This section is from the book "The Balance Of Nature And Modern Conditions Of Cultivation", by George Abbey. Also available from Amazon: The Balance Of Nature And Modern Conditions Of Cultivation.
The Pied Wagtail (Motacilla lugubris), Fig. 40, a member of the sub-family Motacillinae of Dentirostral Insessors and included in the family Sylviadae or Warblers, is notable for its well-known habit of jerking its tail when running or perching. The male is rather more than 7 in. in length, the female slightly over 6 in. from beak to tip of tail. The body is black above, breast, belly, and parts under the tail white. White feathers margin the wings and tail, while the legs and beak are black. In summer the throat is black, but becomes white in winter.
Fig. 40. - The Pied Wagtail.
The pied wagtail inhabits meadow-lands and pastures, and is fond of frequenting ponds, streams and rivers, marshes and flooded meadows. It delights in pastures and fields where cattle and sheep are grazing, and appears in close friendship with them and quickly dispatches tormenting flies, etc., roused by the feet of the animals. The nest of a pied wagtail is built in banks, in crevices among stones, or in the hole of a tree or wall, and always near the water. It is constructed of moss, dried grass, bents, and fine roots, and lined with wool, feathers and other soft materials. The eggs, usually four or five, are bluish-white, with brownish or purple-brown specks. Breeding begins in the spring, and there are often two broods in a season. The food consists of beetles, flies, moths, millipedes, woodlice, snails and slugs, the young being fed with aphides, small caterpillars, and other "soft" insects. The wagtails also scour shallow water of fresh-water molluscs, such as Limnaea truncatula and Limnaea pereger, known as hosts of the liver fluke (Distoma hepaticum), the scourge of the sheep farmer's flocks, and even wade into water after a caddis worm, the plague of watercress beds, and other grubs.
In autumn the pied wagtails move from the more northern to the southern parts of the kingdom, and some evidently pass to warmer climes, yet some remain throughout the winter in this country.