THE ROOK AND HIS KIN. 1T7 
wireworm for five years underground, during almost 
the whole of which time their depredations continue, 
and as both destroy far more than they actually 
devour, it may well be understood that the agricul- 
turist has no more bitter foes, and none whose 
slaughter confers upon him a greater benefit. 
And that these three insects are among the favourite 
food of the rook may be seen from the following 
extracts, which are of so valuable and conclusive a 
character that, although I have already made use of 
them elsewhere, I offer no apology for quoting them 
again. 
The first, which is taken from Mr. Curtis’s valuable 
work upon “ Farm Insects,” and quoted by him from 
the Magazine of Natural History, is as follows :— 
“In the neighbourhood of my native place, in the 
county of York, is a rookery in which it is estimated 
that there are 10,000 rooks; that 1 lb. of food is a 
very moderate allowance for each bird; and that 
nine-tenths of their food consists of worms, insects, 
and their larvee; for, although they do considerable 
damage to the fields for a few weeks in seed-time and 
a few weeks in harvest, particularly in backward 
seasons, yet a very large proportion of their food, 
even at these seasons, consists of Insects and worms, 
which (if we except a few acorns and walnuts in 
autumn) compose at all other times the whole of their 
subsistence. Here, then, if my data be correct, there 
is the enormous quantity of 468,000 Ib., or 209 ons, 
of worms, insects, and their larve destroyed by the 
rooks of a single rookery in one year. To every one 
