CHAPTER X 
PARENTAL AND SEXUAL CHARACTERS 
Mention has been made that among birds, 
for instance, there are many which do not 
present conspicuous colouring, in either sex. 
It has also been shown (under parental 
instincts) how these birds protect their 
young by making themselves conspicuous 
other than by means of colour; similarly 
it has been noted that female protection 
is accomplished in these birds by pre-copu- 
latory displays on the part of the male, 
quite apart from colour. In these crypti- 
cally coloured birds, another male character 
is also possibly used for female protection, 
namely—Song. 
The production of sounds during pre- 
copulatory displays are obviously a part of 
the display. But the songs of birds cannot 
be thus classed. 
Singing birds are conspicuous in nature, 
