88 THE WOODPECKERS 



while the creeper's habits are almost precisely 

 like the woodpecker's, so much so that when 

 we first make his acquaintance, some of us will 

 be sure we have discovered a new kind of wood- 

 pecker, the chimney swift has but one habit 

 in common with the woodpecker, that of cling- 

 ing to an upright surface and propping himself 

 by his tail. If the bird with the tail most like 

 the woodpecker's has the woodpecker's habits, 

 is it not a fair inference that this form of tail is 

 better fitted to this way of living than the other 

 would be ? 



Next, what variations in shapes do we observe 

 among the woodpeckers themselves ? The log- 

 cock and the ivory-billed woodpecker have the 

 longest tails because they are the largest 

 birds. When we compare the length of the 

 tails with the length of the birds we are surprised 

 at the results. On measuring sixteen species, 

 representing seven genera, I find that the tail is 

 from three tenths to thirty-five hundredths of the 

 entire length ; that it is, in proportion, as long 

 in the flicker as in the ivory-bill, as long in the 

 downy as in the logcock, and longer (in the 

 specimens measured) in the almost wholly ter- 

 restial flicker than in the wholly arboreal logcock. 

 Without much more study all that we can safely 

 infer is that the woodpecker's tail is not far from 



