island before the commencement of winter, and proceed to the more
congenial warmth of Africa, to return with the next spring. The causes
assigned by naturalists for this peculiarity are, either a deficiency of
food, or the want of a secure asylum for the incubation and nourishment
of their young. Their migrations are generally performed in large
companies, and, in the day, they follow a leader, which is occasionally
changed. During the night, many of the tribes send forth a continual
cry, to keep themselves together; although one would think that the
noise which must accompany their flight would be sufficient for that
purpose. The flight of birds across the Mediterranean was noticed three
thousand years ago, as we find it said in the book of Numbers, in the
Scriptures, that "There went forth a wind from the Lord, and brought
quails from the sea, and let them fall upon the camp, and a day's
journey round about it, to the height of two cubits above the earth."

922. IF THE BEAUTY OF BIRDS were not a recommendation to their being
universally admired, their general liveliness, gaiety, and song would
endear them to mankind. It appears, however, from accurate observations
founded upon experiment, that the notes peculiar to different kinds of
birds are altogether acquired, and that they are not innate, any more
than language is to man. The attempt of a nestling bird to sing has been
compared to the endeavour of a child to talk. The first attempts do not
seem to possess the slightest rudiments of the future song; but, as the
bird grows older and becomes stronger, it is easily perceived to be
aiming at acquiring the art of giving utterance to song. Whilst the
scholar is thus endeavouring to form his notes, when he is once sure of
a passage, he usually raises his tone, but drops it again when he finds
himself unequal to the voluntary task he has undertaken. "Many
well-authenticated facts," says an ingenious writer, "seem decisively to
prove that birds have no innate notes, but that, like mankind, the
language of those to whose care they have been committed at their birth,
will be their language in after-life." It would appear, however,
somewhat unaccountable why, in a wild state, they adhere so steadily to
the song of their own species only, when the notes of so many others are
to be heard around them. This is said to arise from the attention paid
by the nestling bird to the instructions of its own parent only,
generally disrega