98 THE WOODPECKERS 



tail, and the momentum of a blow delivered from 

 a greater height. When the little hairy wood- 

 pecker does so much with his weak body, we can 

 imagine what great birds like the logcock and 

 the ivory-billed woodpecker, with their tremen- 

 dous beaks, their huge claws, their springy tails, 

 and their great physical strength can do. They 

 are magnificent birds, the terror of all the grubs 

 that hide in tree-trunks. 



One point we have left unexplained : What 

 is the advantage, if there is any, in the sharper 

 curve to the tails of the arboreal woodpeckers ? 

 It is a simple question. The curve is caused by 

 the unequal length of the tail feathers ; each 

 tail feather is a prop, and by their inequality 

 they become props of different lengths. Now 

 ask any carpenter which will best support a 

 tottering wall props all of the same length 

 set at the same angle, or props of different 

 lengths set at different angles ? His answer 

 will help you to solve the problem. But if a 

 little is good, why are not all the pairs used as 

 props ? Partly, perhaps, because the woodpecker 

 is always crowded for houseroom, and while he 

 must have tail enough, he cannot afford to have 

 any which he does not use. Did you ever think 

 what an inconvenience any tail at all must be in 

 a woodpecker's hole ? 



