50 FOREHEAD OF THE ROOK. 
tagu says, that it is acquired by the bird's " habit 
of thrusting its bill into the ground after worms and 
various insects." From the study of Professor 
Rennie, this error is renewed to the public, in the 
second edition of the Ornithological Dictionary, 
Let us look into this error. 
Every observer of birds must know that when the 
young rook leaves its nest for good and all, there is 
no part of its head deficient in feathers. Before 
winter, this young bird loses the feathers on the | 
forehead, under the bill, and at the base of both j 
mandibles. The skin where these feathers grew I 
puts on a white scurfy appearance. Now, if these \ 
feathers had been worn down to the stumps by \ 
means of the bird thrusting its bill into the ground, > 
these stumps would fall out at the regular moult- j 
ing time, and new feathers would soon make their f 
appearance. If, again, these feathers have been l 
loosened at their roots by the process of thrusting | 
the bill into the ground (which I consider next to j 
impossible), and in consequence of this have fallen j 
out from their places, new feathers would be observed! 
in a few weeks; for when once a feather is eradi-i 
cated, nature instantly sets to work to repair the loss 
by producing another ; nor do we know of any process 
that can be applied with success, to counteract this! 
admirable provision of nature. Again ; these new 
feathers being full of blood at the roots, any appli- 
cation tending to grind them down, or to eradicate 
them, would be so painful to the rook, that it! 
would not be able to thrust its bill deep into th^' 
ground. I 
