570 NORTH AMERICAN BIRDS. 



large enough to receive one acorn at a time. They are packed in, one above 

 the other, until the cavity is full. How did these Woodpeckers first learn 

 to thus use these storehouses, by nature closed against them ? The intelli- 

 gent instinct that enabled this bird to solve this problem Saussure regarded 

 as not the least surprising feature. With its beak it pierces a small round 

 hole through the lower portion into the central cavity, and thrusts in acorns 

 until the hollow is filled to the level of the hole. It then makes a second 

 opening higher up, and fills the space below in a like manner, and so pro- 

 ceeds until the entire stalk is full. Sometimes the space is too small to re- 

 ceive the acorns, and they have to be forced in by blows from its beak. In 

 other stalks there are no cavities, and then the Woodpecker creates one for 

 each acorn, forcing it into the centre of the pith. 



The labor necessary to enable the bird to accomplish all this is very con- 

 siderable, and great industry is required to collect its stores ; but, once col- 

 lected, the storehouse is a very safe and convenient one. Mount Pizarro is 

 in the midst of a barren desert of sand and volcanic debris. There are no 

 oak-trees nearer than the Cordilleras, thirty miles distant, and therefore the 

 collecting and storing of each acorn required a flight of sixty miles. 



This, reasons Saussure, is obviously an instinctive preparation, on the 

 part of these birds, to provide the means of supporting life during the arid 

 winter montlis, when no rain falls and everything is parched. His observa- 

 tions were made in April, the last of the winter months ; and he found 

 the W^oodpeckers withdrawing food from their depositories, and satisfied 

 himself that the birds were eating the acorn itself, and not the diminutive 

 maggots a few of them contained. 



The ingenuity with which the bird managed to get at the contents of each 

 acorn was also quite striking. Its feet being unfit for grasping the acorn, it 

 digs a hole into the dry bark of the yuccas, just large enough to receive the 

 small end of the acorn, which it inserts, making use of its bill to split it 

 open, as with a wedge. The trunks of the yuccas were all found riddled 

 with these holes. 



There are several remarkable features to be noticed in the facts observed 

 by Saussure,- — the provident instinct which prompts this bird to lay by 

 stores of provisions for the winter ; the great distance traversed to collect 

 a kind of food so unusual for its race ; and its seeking, in a spot so remote 

 from its natural abode, a storehouse so remarkable. Can instinct alone 

 teach, or have experience and reason taught, these birds, that, better far than 

 the bark of trees, or cracks in rocks, or cavities dug in the earth, or any 

 other known hiding-place, are these hidden cavities within the hollow stems 

 of distant plants ? What first taught them how to break througli the flinty 

 coverings of these retreats ? By what revelation could these birds have 

 been informed that within these dry and closed stalks they could, by search- 

 ing, find suitable places, protected from moisture, for preserving their stores 

 in a state most favorable for their long preservation, safe from gnawing 



