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 
mandibles. The skin where these feathers grew 
puts on a white scurfy appearance. Now, if these 
feathers have 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 moulting 
time, and new feathers would soon make their ap- 
pearance. If, again, these feathers have been loos- 
ened at their roots by the process of thrusting the 
bill into the ground (which I consider next to im- 
possible), and in consequence of this have fallen 
out from their places, new feathers would be observed 
in a few weeks ; for when once a feather is eradi- 
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 the ground. 
