that
the other inmates of the nest are maliciously thrown out. Others,
again, say that the foster birds throw their own young ones out. It
is certain that the young are sometimes treated thus, for they have
been seen on the ground when the young cuckoo was too small to eject
them itself.

[Illustration: CUCKOO.]

"But why do not cuckoos make nests and sit on their eggs like other
birds?" said Jack. Such a question is more easily asked than answered;
nevertheless I hope you will always try to discover reasons for
things. "It is now," writes a celebrated naturalist, "commonly
admitted that the more immediate and final cause of the cuckoo's
instinct is, that she lays her eggs, not daily, but at intervals of
two or three days; so that if she were to make her own nest and sit on
her own eggs, those first laid would have to be left for some time
unincubated, or there would be eggs and young birds of different ages
in the same nest. If this were the case the process of laying and
hatching might be inconveniently long, more especially as she has to
migrate at a very early period, and the first hatched young would
probably have to be fed by the male alone." The cuckoos come to this
country about the middle of April; the male birds arrive before the
females. Whether this arrangement is ungallant conduct on the part of
the gentlemen birds, who prefer to come alone, or whether, just when
the gentleman cuckoo is ready and almost impatient for a start, her
ladyship has all at once discovered some important matter that ought
to be finished before leaving the country, some adjustment of her
dress, some tiresome feather that will ruffle itself up in spite of
every effort to keep it smooth, I know not, but the fact remains, that
my Lord and Lady Cuckoo do not travel together. Let us suppose that
both sexes have arrived in this country, we will say about the 23rd of
April. It is natural they want a little time to look about them; at
any rate, no egg is ready for being sat upon till some weeks after the
arrival of the birds, say the 15th of May. The eggs require fourteen
days' setting before they are hatched; this brings the date to the
29th of May. The young ones will require three weeks in the nest and
constant feeding all the time; we now arrive at about the 20th of
June, when the young ones would be ready to leave the nest. But they
want five weeks' more feeding by the parents, after they leave the
nest, before they are able to pro