functions connected with the reproduction of the species. Many
instances have already been given of the partial transference of
secondary masculine characters to the female, so that it is not at all
surprising that the females of some species should possess the power of
song. It has also been argued, that the song of the male cannot serve
as a charm, because the males of certain species, for instance of the
robin, sing during the autumn. (33. This is likewise the case with the
water-ouzel; see Mr. Hepburn in the Zoologist, 1845-46, p. 1068.) But
nothing is more common than for animals to take pleasure in practising
whatever instinct they follow at other times for some real good. How
often do we see birds which fly easily, gliding and sailing through the
air obviously for pleasure? The cat plays with the captured mouse, and
the cormorant with the captured fish. The weaver-bird (Ploceus), when
confined in a cage, amuses itself by neatly weaving blades of grass
between the wires of its cage. Birds which habitually fight during the
breeding-season are generally ready to fight at all times; and the
males of the capercailzie sometimes hold their Balzen or leks at the
usual place of assemblage during the autumn. (34. L. Lloyd, Game Birds
of Sweden, 1867, p. 25.) Hence it is not at all surprising that male
birds should continue singing for their own amusement after the season
for courtship is over.
As shewn in a previous chapter, singing is to a certain extent an art,
and is much improved by practice. Birds can be taught various tunes,
and even the unmelodious sparrow has learnt to sing like a linnet. They
acquire the song of their foster parents (35. Barrington, ibid. p. 264,
Bechstein, ibid. s. 5.), and sometimes that of their neighbours. (36.
Dureau de la Malle gives a curious instance ( Annales des Sc. Nat. 3rd
series, Zoolog., tom. x. p. 118) of some wild blackbirds in his garden
in Paris, which naturally learnt a republican air from a caged bird.)
All the common songsters belong to the Order of Insessores, and their
vocal organs are much more complex than those of most other birds; yet
it is a singular fact that some of the Insessores, such as ravens,
crows, and magpies, possess the proper apparatus (37. Bishop, in
Todd s Cyclopaedia of Anatomy and Physiology, vol. iv. p. 1496.),
though they never sing, and do not naturally modulate their voices to
any great extent. Hunter asserts (38. As stated by Barrington in
Philosophical Transactions, 1773, p. 262.) that with the true
songsters the muscles of the larynx are stronger in the males than in
the females; but with this slight exception there is no difference in
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