194 Union Bay 



so scientists persist in evolving theories and in testing their 

 validity. 



Joseph Grinnell, in his Philosophy of Nature, makes these 

 statements: 



The more I reflect upon the observed actions of birds, and of ani- 

 mals generally, the more I am convinced that there is no such thing 

 as wasted effort. . . . Really, every movement, every phase of activity, 

 has its explicit meaning in the bird's program of maintaining existence. 



That means that such habits are not accidental or useless but 

 serve some purpose that may or may not be concealed. 



If I accepted this premise I thought that it' should not be 

 too difficult to discover why our spotted sandpiper went 

 through its sinuous bobbing motions. The bird's problem is 

 to maintain existence. Food, shelter, survival, and reproduc- 

 tion are concerned with this problem. There should be some 

 simple connection between these motions and the bird's 

 needs. 



I recalled the people I have talked with and the books and 

 articles I have read. I was quite impressed by the arguments 

 of a physician, a serious bird student with a great interest in 

 optics. He said that when a person tries to look beneath the 

 surface of water he invariably raises and lowers his head 

 until it reaches an angle which gives him the best view. He 

 thought it quite likely that shorebirds bobbed and teetered 

 to obtain the same results. It appeared to be the most reason- 

 able explanation I had heard, but it hardly explained why 

 the pipits wagged their tails while hunting grasshoppers on 

 the heights of Welcome Pass. 



I found a statement by Bradford Torrey: 



Can it be that such frequenters of shallow water are rendered less 

 conspicuous by this wave-like up-and-down motion, and have actually 

 adopted it as a means of defense, just as they and many mere have 

 taken on a color harmonizing with that of their ordinary surroundings? 



