The Green Woodpecker. 15 
off or escaping, and when this method is inconvenient 
it will drag out the insect, using the barbs asa 
sort of rake. But there is yet another provision 
vouchsafed by the wonderful economy of Nature. 
On each side of the head there is a gland (Fig. 2), 
which secretes a strong mucilage, and these olands 
are so connected with the tongue that it becomes 
sticky at the moment in which it is thrust out to 
capture an insect. 
The Woodpecker’s tail is as interesting to examine 
as the tongue, being strangely modified to suit its 
requirements. We have said that the tail is kept 
pressed down upon the tree when the bird is climbing, 
and for a very good reason, as the tail thus affords a 
large amount of support. It is composed of wiry 
elastic feathers, each of which is wedge-shaped at 
the end, and beyond this it is curious to note that 
not only is each feather so shaped, but the whole 
tail is in the form of a wedge, the middle feather 
being the longest, and the rest tapering away on 
each side (Fig. 5, p. 26). It is when the bird is 
pecking at a tree that the utility of the tail is shown 
to the best advantage, for it then serves, one might 
almost say, as a third leg. As the bird clings to the 
bark with its feet, it throws its head right back to 
strike a blow, and the tail then acts as a support 
behind, and prevents it from falling backwards. 
