THE ROOK. 
139 
trace their misfortunes to her crowing hen. How- 
ever, the experiment with the two young rooks, 
though not perfect, has nevertheless been of some 
use. It has shown us that the carrion crow makes 
no distinction betwixt its own eggs and those of the 
rook ; that it can know nothing of the actual time 
required to sit upon eggs in order to produce the 
young ; that the young of the rook will thrive under 
the care of the carrion crow, just as well as under 
that of its own parents ; and, finally, that the feathers 
fall off from the root of the rook's bill by the order 
of nature, as was surmised by the intelligent Bewick, 
and not by the process of the bird's thrusting its 
bill into the earth, in search of food, as is the opinion 
of some naturalists. 
The rook advances through the heavens with a 
very regular and a somewhat tardy beat of wing ; 
but it is capable of proceeding with great velocity 
when it chooses : witness its pursuit and attack on 
the sparrowhawk and kestrel. It is apt to injure, 
in the course of time, the elm trees on which it 
builds its nest, by nipping off the uppermost twigs. 
But this, after all, is mere conjecture. The damage 
may be caused by an accumulation of nests, or by 
the constant resort of such a number of birds to 
one tree. Certain, however, it is, that, when rooks 
have taken possession of an elm tree for the purpose 
of incubation, the uppermost branches of that tree 
are often subject to premature decay. 
Though the flocks of rooks appear to have no 
objection to keep company, from time to time, with 
the carrion crows, in a winter's evening, before they 
