826. Motacilla alba.
The White Wagtail.
Motacilla alba, Linn. Syst. Nat. i, p. 331 (1766) ; Hume, Cat. no. 591 ter; Scully, S. F. viii, p. 314; Oates, B. B. i, p. 156 ; Sharpe, Cat. B. M. x, p. 464. Motacilla dukhunensis, Sykes, P. Z. S. 1832, p. 91; Blyth, Cat. p. 137; Horsf. & M. Cat. i, p. 349; Brooks, S. F. ii, p. 457, vii, p. 137; Hume, Cat. no. 591 bis; Barnes, Birds Bom. p. 236.
Coloration. In normal full summer plumage, the forehead, anterior portion of crown, sides of the head and of the neck are pure white; remainder of crown, nape, and hind neck, chin, throat, fore neck, and breast deep black; upper plumage, scapulars, and lesser wing-coverts grey ; upper tail-coverts more or less black, margined exteriorly with white; wing-coverts and tertiaries blackish, broadly margined with white; primaries and secondaries black, narrowly margined with whitish; the four middle pairs of tail-feathers black, the others nearly entirely white; lower plumage from the breast downwards pure white.
In normal winter plumage the chin, throat, and fore neck become white, and the black on the breast is reduced to a narrow crescentic patch, sometimes extending narrowly up the sides of the fore neck.
The nestling is uniform greenish ashy above, and the lower plumage is yellowish grey with indications of a pale pectoral crescent.
After the first autumn moult, the young bird resembles the adult in normal winter plumage, but has the posterior part of the crown, the nape, and the hind neck grey like the back, and the white parts of the head tinged with primrose-yellow.
The full summer plumage is probably assumed the first spring, except in the case of the females, which appear to be much longer than the males in acquiring the black on the crown, nape, and hind neck, these parts being at first a pale brown, and afterwards for some time black mottled with brown.
Bill black, bluish below ; iris brown ; legs and claws dark brown or nearly black.
Length nearly 8; tail 3.6; wing 3.5; tarsus .85; bill from gape .75.
Distribution. A winter visitor to the whole Empire, as far south in the peninsula of India as Belgaum, and in Burma as Moulmein. A few specimens of this species are occasionally killed in summer, and I have seen a July specimen from Sambhar. Indian birds of this species appear to winter in Northern Asia. The range of this Wagtail extends to Europe and Northern Africa.
M. baicalensis is a race of M. alba with the wing-coverts almost entirely white. It inhabits Eastern Siberia, and in the British Museum there is a specimen said to have been killed in " India." No reliance can, however, be placed on this locality.
M. persica is another race of M. alba, with the wing-coverts almost entirely white, and the black of the hind neck almost in contact with the black of the breast. It inhabits Persia.