54 
SEXUAL SELECTION : BIEDS. 
Part II. 
the sake of charming the female, is not at all incom- 
patible ; and, indeed, might have been expected to go 
together, like decoration and pugnacity. Some authors, 
however, argue that the song of the male cannot serve 
to charm the female, because the females of some few 
species, such as the canary, robin, lark, and bullfinch, 
especially, as Bechstein remarks, when in a state of 
widowhood, pour forth fairly melodious strains. In 
some of these cases the habit of singing may be in part 
attributed to the females having been highly fed and 
confined,^^ for this disturbs all the usual functions con- 
nected Avith the reproduction of the species. Many in- 
stances have already been given of the partial trans- 
ference 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 in- 
stance, of the robin, sing during the autumn.^ But 
nothing is more common than for animals to take plea- 
sure ill practising whatever instinct they follow at other 
times for some real good. Hoav often do we see birds 
which fly easily, gliding and .sailing through the air 
obviously for pleasure. The cat plays with the cap- 
tured 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 betAveen. 
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 some- 
times hold their halzens or leks at the usual place of 
32 D. Barrington, ‘ Phil. Transact.’ 1773, p. 262. Bechstein, ‘ Stu- , 
benvogel,’ 1810, s. 4. 
This is likewise the case with the water-ouzel, see Mr. Hepburui 
in the ‘Zoologist,’ 1845-1846, p. 1068. 
