on must account for the presence of the myrtle,
with its small blue berry; the laurustinus with its currant-like fruit;
the elder-tree, the canary laurel, the local sweet-gale, and the
peculiar juniper. Before these shrubs were introduced thus
unconsciously by our feathered guests, there were no fruits on which
berry-eating birds could live; but now they are the only native trees
or large bushes on the islands--I mean the only ones not directly
planted by you mischief-making men, who have entirely spoilt my nice
little experiment.

It was much the same with the history of some among the birds
themselves. Not a few birds of prey, for example, were driven to my
little archipelago by stress of weather in its very early days; but
they all perished for want of sufficient small quarry to make a living
out of. As soon, however, as the islands had got well stocked with
robins, black-caps, wrens, and wagtails, of European types--as soon as
the chaffinches had established themselves on the seaward plains, and
the canary had learnt to nest without fear among the Portugal
laurels--then buzzards, long-eared owls, and common barn-owls, driven
westward by tempests, began to pick up a decent living on all the
islands, and have ever since been permanent residents, to the immense
terror and discomfort of our smaller song-birds. Thus the older the
archipelago got the less chance was there of local variation taking
place to any large degree, because the balance of life each day grew
more closely to resemble that which each species had left behind it in
its native European or African mainland.

I said a little while ago we had no mammal in the islands. In that I
was not quite strictly correct. I ought to have said, no terrestrial
mammal. A little Spanish bat got blown to us once by a rough
nor'easter, and took up its abode at once among the caves of our
archipelago, where it hawks to this day after our flies and beetles.
This seemed to me to show very conspicuously the advantage which winged
animals have in the matter of cosmopolitan dispersion; for while it was
quite impossible for rats, mice, or squirrels to cross the intervening
belt of three hundred leagues of sea, their little winged relation, the
flitter-mouse, made the journey across quite safely on his own leathery
vans, and with no greater difficulty than a swallow or a wood-pigeon.

The insects of my archipelago tell very much the same story as the
birds and the plants. Here, t