156 BOMBAY DUCKS 
The hen bird differs but slightly from the male. She 
has the crimson chest, but the feathers of her head, 
instead of being tipped with crimson, are spotted with 
white. That so trivial a difference should be due to 
sexual selection I find it difficult to believe. The 
species nests in holes in trees; hence there is no reason 
why, so far as protection is concerned, the hen should 
not exactly resemble the cock in outward appearance. 
This is by no means the only point in the colouring 
of the woodpecker which needs elucidation. 
Although the tribe displays a great variety of colour, 
no tint of blue is, I believe, ever seen in the plumage. 
Again, the young birds of some species are more gaily 
coloured than the adults—a most unusual phenomenon. 
The woodpecker, being a highly specialized bird, is a 
perfect example of adaptation to environment. Its 
peculiar form is the expression of its unusual habits. 
Its beak is powerful, and is used asa pickaxe. With 
it the bird can excavate a nest in decaying wood, or 
dig out the insects which lurk in rotten timber. The 
bird also, by tapping its beak, frightens out of their 
lair insects which are hiding in the bark; and woe 
betide them when once they show themselves! 
The woodpecker is provided with a chameleon-like 
tongue, which is armed with backwardly-directed bristles 
and a plentiful secretion of saliva of the “ stick-fast” 
variety. The tongue is shot out at the insect with 
lightning speed, and in less than the twinkling of an 
eye the luckless creature is being hustled down the 
woodpecker’s gullet. 
One enthusiast thus describes the bird’s tongue : 
