20 Wild Birds, Useful and Injurious. 
character for usefulness or the reverse. There cannot be much 
doubt, however, that in many districts rooks are too numerous, 
and that the greater their numbers, the greater is the harm 
they do in comparison with the benefits they confer. The 
home-bred birds are augmented by vast hordes, which come 
to us from the Continent in October and November. 
Rooks consume very large quantities of corn, particularly 
at seed-time, and castings composed entirely of the husk of 
oats may often be found underneath the trees of a rookery. 
They also do considerable damage at harvest, and not un- 
frequently attack ricks left in the field. It is advisable, 
however, to open any rooks shot on newly sown land, for they 
often contain a quantity of wire- worms or othei grubs, with 
only a few gi’ains of corn. There is, too, a simple method of 
preventing depredation, for a dressing of tar applied to the 
seed corn has proved very effective. Perhaps the most annoy- 
ing injury caused by rooks is the destruction of potatoes, which 
they unearth at seed-time as well as later in the season. They 
also pull up acres of turnips after they are singled, though in 
this case they are undoubtedly looking for grubs ; and in 
winter peck holes in the roots, causing them to rot. Walnuts 
have a great attraction for them, and the same may be said 
of cherries and other fruit. Their taste for eggs is now well 
known ; many nests of game-birds are plundered, and there 
can be little doubt that the eggs and young of skylarks and 
other ground-building birds share a similar fate. 
As is usually the case, the harm done by the birds is 
obvious, and it is possible to form an approximate idea of the 
damage. On the other hand, the good they do often escapes 
observation, and it is impossible to estimate the value of their 
services. It may, however, be pointed out that a very large 
proportion of their time is spent on grass fields and on newly 
ploughed land, where their presence can only be beneficial, 
and that they consume enormous quantities of wire-worms, 
leatherjackets, cockchafer grubs, slugs and surface caterpillars, 
as well as earthworms, clickbeetles, daddy longlegs, and other 
insects of all sorts and descriptions. Some of the insects are 
no doubt useful, for instance the ground-beetles which prey 
upon other species, and it appears that rooks eat a considerable 
quantity of them. A complete list of the food of the rook 
would comprise almost every edible substance, for it is practi- 
cally omnivorous, devouring carrion, bread, feeding-cakes, 
bone-meal, fish, shell-fish, small birds — even lapwings — the 
fleshy roots of couchgrass and other plants, maize, acorns, 
beechmast, and bilberries. An interesting account of an 
organised hunt for field mice by a flock of rooks appeared 
in The Zoologist for 1892, and I have taken the remains of 
