The Green Woodpecker. 15 



off or escaping, and when this method is inconvenient 

 it will drag out the insect, using the barbs as a 

 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 glands 

 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. 



