246 



USEFUL BIRDS. 



draws back his head and body to the greatest possible dis- 

 tance from the tree, and then strikes with all his force, send- 

 ing his strong beak powertiilly into the wood. The skull of 

 the typical Woodpecker is very thick and hard. Its connec- 

 tion with the beak is strong, but at the same time springy, 

 and somewhat jar-deadening. The membrane which sur- 

 rounds the brain is very thick and strong. 



jNIaurice Thompson says that no person can doubt, after 

 an examination of Woodpecker habits, that the birds are 

 hard of hearing. He apparently believes that the continual 

 concussion has deadened this sense. However this may be, 

 it has not interfered with the bird's sight, which seems pre- 

 ternaturally keen . 



The bill is shaped somewhat like a stout chisel, and is used 

 as one. It strikes out small chips, and so drills its way, if 



necessary, even to the 

 heart of the tree ; but 

 the most highl}' spe- 

 cialized organ of the 

 Woodpecker is its 

 tongue, which serves 

 as an accessory to the 

 bill in brino-ino: to 

 light the deep-lurking 

 enemies of the tree. 

 The subjoined cut of the AVoodpecker's skull (Fig. 103) 

 shows the tongue slightlj^ protruding from the open beak. 

 Ordinarily the tongue lies in the depression of the lower 

 mandible. It is slender, nearly round, and its upper sur- 

 face is covered with very minute 

 spines, directed backward ; its tip 

 is as hard as horn, with many 

 strong barbs, which make of it a 

 weapon more etfective in its way 

 than a fish spear. The machinery 

 for thrusting it forth is most perfect. The bone of the 

 tongue, called the hyoid, has two branches wdiich pass down- 

 ward and backward from the lower jaw, up and around the 

 back of the head, and over the top of the skull, where they 



Fig. 103. — Skull and tongue of Woodpecker. 

 (From Samuels.) 



Fig. 104. — Spearlike tongue-tip 

 of Downy Woodpecker, much 

 enlarged. 



