A strong prejudice is felt by many persons against Rooks, on
account of their destroying grain and potatoes, and so far is this
prejudice carried, that I know persons who offer a reward for
every Rook that is killed on their land; yet so mistaken do I deem
them as to consider that no living creature is so serviceable to
the farmer as the Rook, except his own live stock.
In the neighbourhood of my native place is a rookery belonging to
William Vavasour Esq., of Weston in Wharfdale, in which it is
estimated there are 10,000 Rooks, that 1 lb. of food a week is a
very moderate allowance for each bird, and that nine-tenths of
such food consists of worms, insects, and their larvae: for
although they do considerable damage to the crops for a few weeks
in seed-time and harvest, particularly in backward seasons, yet a
very large proportion of their food, even at these times, consists
of insects and worms, which (if we except a few acorns, walnuts,
and potatoes in autumn) at all other times form the whole of their
subsistence.
Here, then, if my data be correct, there is the enormous quantity
of 468,000 lbs., or 209 tons of worms, insects, and their larvae
destroyed by the birds of a single rookery, and to everyone who
knows how very destructive to vegetation are the larvae of the
tribes of insects (as well as worms) fed upon by Rooks, some
slight idea may be formed of the devastation which Rooks are the
means of preventing. I have understood that in Suffolk and in some
of the southern counties, the larvae of the cockchafer are so
exceedingly abundant that the crops of corn are almost destroyed
by them, and that their ravages do not cease even when they have
become perfect insects. Various plans have been proposed to put a
stop to their ravages, but I have little doubt that their
abundance is to be attributed to the scarcity of Rooks, as I have
somewhere seen an account that these birds are not numerous in
those counties (I have never been there), either from the trees
being felled in which they nested, or from their having been
destroyed by the prejudiced farmer. I am the more inclined to be
of this opinion, because we have many Rooks in this neighbourhood
where the cockchafer is not known as a destructive insect, and I
know that insects of that class and their larvae are the most
favourite food of the Rook, which may be seen in the twilight
catching both cockchafers and the large blackbeetles which are
flying at that time in the evening.
I will mention another instance of the utility of the Rook which
occurred in this neighbourhood. Many years ago a flight of locusts
visited Craven, and they were so numerous as to create considerable
alarm among the farmers of the district. They were, however, soon
relieved from their anxiety, for the Rooks flocked in from all
quarters by thousands and tens of thousands, and devoured the
locusts so greedily that they were all destroyed in a short time.
Such, at least, is the account given, and I have heard it repeatedly
mentioned as the reason why the late Lord Ribblesdale was so partial
to Rooks. But I have no means of ascertaining how far this is true.
It was stated in the newspapers a year or two back that there was
such an enormous quantity of caterpillars upon Skiddaw, that they
devoured all the vegetation on the mountain, and people were
apprehensive they would attack the crops in the enclosed lands;
but the Rooks (which are fond of high ground in the summer) having
discovered them, put a stop to their ravages in a very short time.
(June 30th, 1832.)
These remarks are confirmed by a writer in the "Essex Herald" and
by Mr. Waterton. The former says:--"An extensive experiment
appears to have been made in some of the agricultural districts on
the Continent, the result of which has been the opinion that
farmers do wrong in destroying Rooks, Jays, Sparrows, and, indeed,
birds in general on their farms, particularly where there are
orchards."
That birds do mischief occasionally among ripe corn there can be
no doubt; but the harm they do in autumn is amply compensated by
the good they do in spring by the havoc they make among the insect
tribes. The quantity of grubs destroyed by Rooks and of
caterpillars and grubs by the various small birds, must be
annually immense. Other tribes of birds which feed on the wing--as
Swifts, Swallows, and Martins--destroy millions of winged insects
which would otherwise infest the air and become insupportably
troublesome. Even the Titmouse and the Bullfinch, usually supposed
to be so mischievous in gardens, have actually been proved only to
destroy those buds which contain a destructive insect. Ornithologists
have of late determined these facts to be true, and parish officers
would do well to consider them before they waste the public money
in paying rewards to idle boys and girls for the heads of dead birds,
which only encourages children and other idle persons in the
mischievous employment of fowling instead of minding their work or
their schooling. But to return to the experiment alluded to. On some
very large farms in Devonshire the proprietors determined a few
summers ago to try the result of offering a great reward for the
heads of Rooks, but the issue proved destructive to the farms, for
nearly the whole of the crops failed for three succeeding years, and
they have since been forced to import Rooks and other birds wherewith
to re-stock their farms.
Of late years the extensive destruction of the foliage and young
fruit in orchards by a species of caterpillar has excited the
attention of the naturalist, and it has been found to have arisen
from the habit of destroying those small birds about orchards
which if left unmolested would have destroyed or kept down those
rapacious insects.
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