opulation annually produced? It is evident they must all die or be
killed, somehow; and as the increase is, on the average, about five to
one, it follows that, if the average number of birds of all kinds in our
islands is taken at ten millions--and this is probably far under the
mark--then about fifty millions of birds, including eggs as possible
birds, must annually die or be destroyed. Yet we see nothing, or almost
nothing, of this tremendous slaughter of the innocents going on all
around us. In severe winters a few birds are found dead, and a few
feathers or mangled remains show us where a wood-pigeon or some other
bird has been destroyed by a hawk, but no one would imagine that five
times as many birds as the total number in the country in early spring
die every year. No doubt a considerable proportion of these do not die
here but during or after migration to other countries, but others which
are bred in distant countries come here, and thus balance the account.
Again, as the average number of young produced is four or five times
that of the parents, we ought to have at least five times as many birds
in the country at the end of summer as at the beginning, and there is
certainly no such enormous disproportion as this. The fact is, that the
destruction commences, and is probably most severe, with nestling birds,
which are often killed by heavy rains or blown away by severe storms, or
left to die of hunger if either of the parents is killed; while they
offer a defenceless prey to jackdaws, jays, and magpies, and not a few
are ejected from their nests by their foster-brothers the cuckoos. As
soon as they are fledged and begin to leave the nest great numbers are
destroyed by buzzards, sparrow-hawks, and shrikes. Of those which
migrate in autumn a considerable proportion are probably lost at sea or
otherwise destroyed before they reach a place of safety; while those
which remain with us are greatly thinned by cold and starvation during
severe winters. Exactly the same thing goes on with every species of
wild animal and plant from the lowest to the highest. All breed at such
a rate, that in a few years the progeny of any one species would, if
allowed to increase unchecked, alone monopolise the land; but all alike
are kept within bounds by various destructive agencies, so that, though
the numbers of each may fluctuate, they can never permanently increase
except at the expense of some others, which must proportionately
decrea