I2O Summer Studies of Birds and Books CHAP. 



of the motion is to aid the bird in balancing itself. 

 It is true enough, no doubt, that the tail of every 

 bird is of use to it in this way, especially in the air ; 

 but the peculiar motion of the tails I am writing of 

 cannot possibly be needed for this purpose. If the 

 bird were likely to topple over into the water while 

 sitting on the edge of a stone, a supposition in 

 itself absurd, I imagine that it would most natu- 

 rally keep its tail well down, rather than wave it 

 up and down rapidly. But surely no bird needs 

 any peculiar action to enable it to keep its equi- 

 poise ; even a sparrow without a tail can do this 

 perfectly well. Again, if the Wagtails need long 

 tails and a peculiar motion to keep them steady, 

 how does the Dipper manage a bird that needs 

 balancing on slippery stones as much at least as 

 they ? His tail is short, his form less shapely than 

 that of a Wagtail, and as he sits on the edge of a 

 stone making bows at you, he takes no such pre- 

 cautions to save himself from a tumble as in his 

 ignorance of a bird's make and habits this writer 

 attributes to the Wagtails. 



For several years I have closely observed the 

 tail-motions, not only of Wagtails, but of a great 

 variety of birds, and I may fairly venture to express 

 an opinion about them. It is a familiar fact that 

 many animals use their tails to express certain 

 emotions ; for the tail is directly connected with the 



