IN THE SHETLANDS Qi 
female not rising to the height of such a definition. 
To how great an extent this law prevails I have not 
the knowledge to say, but it is not universal. The 
female canary, robin, lark, and bullfinch all sing, 
especially when widowed, though their song is not 
equal to that of the male, whilst in the red oven-bird 
of Argentina both sexes frequently join one another 
for the express purpose of singing a duet. Surely in 
this last case, especially, if it be assumed that the song 
of the male is uttered with the purpose of pleasing 
the female, or has that effect, the converse ought also 
to be assumed : and if so, why should not the hens, 
as well as the cocks, be sometimes chosen for their 
song ? 
But all nuptial notes of birds are equally song, in 
the sense that they are uttered under the impulse of 
sexual passion, and many of these are the same in 
both the sexes. Here, again, there is a danger of 
assuming, without sufficient evidence, that the char- 
acteristic courting or love-note is uttered only by 
the male. A mistake of this kind has been made in 
the case of the nightjar—both sexes of which I have 
heard “‘churr” together on the nest—and no doubt 
in many other instances, including, very possibly, the 
cuckoo. In a vast number of cases, however, the 
cries of the two sexes during the love-season are 
known to be the same. They may not always, when 
this is the case, be either very wonderful or very 
beautiful, but to suppose that the nuptial actions and 
notes of male birds are intended to attract and charm 
