TH ROOK AND HIS KIN. 123 
spot perpendicularly under them by any other pro- 
cess so short and rapid.” 
Such is Waterton’s comment upon the subject, in 
which, however, he fails to explain why it is that the 
birds should at one time ascend to so great a height, 
while at others they content themselves with a much 
lower elevation. 
As already stated, the rook may be easily distin- 
guished from the carrion crow, which otherwise it 
much resembles, by the fact that the skin at the base 
of the bill is destitute of feathers. It was for many 
years supposed that this nudity was due to the fre- 
quency with which the beak is thrust into the ground, 
the feathers being in consequence worn down by the 
incessant friction. But this theory has been shown 
to be altogether incorrect, for not only do the feathers 
fall out in rooks brought up by hand, although their 
owner has never had an opportunity of plunging its 
beak into the ground at all, but the growth of the 
feathers in the wild bird wholly ceases, whereas, were 
they merely worn away, Nature would as constantly 
attempt to replace their loss. 
