212 
MOTACILLID.E. 
with green; the head darkens by degrees, and the forehead 
becomes of a dirty yellowish-Avhite. 
Great changes yet remain to be effected before the spring 
plumage is attained. These changes used to be attributed 
to the actual shedding and renewing of the feathers in spring, 
as Avell as in autumn ; but later observations appear to con¬ 
tradict this supposition, and we are assured by Mr. Yarrell, 
that these changes of colour take place in the feather itself; 
and, consequently, that the Wagtail is subject only to a 
single and not a double moult. 
The entire length of the Pied Wagtail is seven inches and 
a half. The beak from the tip to the forehead measures five 
lines. The wing from the carpus to the tip is nearly three 
inches and a half. The tail-feathers measure three inches 
and three quarters, and extend two and a half inches beyond 
the tips of the folded wings. The tarsus measures eleven 
lines, and the expanse of the foot, from the tip of the hinder 
to that of the middle claw, one inch and four lines. In 
this species Avhen the wing is closed, the first, second, and 
third quill-feathers, and the tip of the longest tertial, are of 
equal length. The twelve feathers of the tail are nearly 
equal in length ; the central pair, although the broadest at 
the base, are much narrowed towards the tip : the upper tail 
coverts are very long, covering nearly half the tail. 
The female of this species is half an inch less in entire 
length, and all other measurements in proportion. 
The adult male in winter plumage, as represented in the 
loAver figure of Plate 85, from a specimen shot in December, 
is as follows :—crown of the head and nape, crescent upon the 
breast, rump, and upper tail-coverts, and the eight middle 
feathers of the tail, perfect inky black : the head and rump 
with purple reflections. The back and scapulars are also 
black, but the feathers in the middle of the back broadly 
fringed with hoary ash, slightly tinged with green. The 
