THE GREEN WOODPECKER. 



aesthetic preference. Dominant types always 

 show these peculiarities. His ground-tone 

 of green, indeed, serves, no doubt, a mainly 

 protective function, by enabling him to escape 

 notice among the leaves of the woodland ; 

 and even on a tree-trunk he readily assi- 

 milates with the tone of the background ; 

 but his brilliant crimson cap is a genuine 

 piece of decorative adornment, which owes 

 its origin, no doubt, to the selective pre- 

 ferences of his female ancestors for endless 

 generations. 



2 43 



