LEAF AND TENDRIL 



stronger the light, the more the pigments are devel- 

 oped. All fish that I am acquainted with are light 

 beneath and dark above. If this condition helps 

 to conceal them from their enemies, it is merely 

 incidental, and not the result of laws working to 



that end. 



Ill 



" The danger of the mother bird during incuba- 

 tion " is a phrase often used by Darwin and by more 

 recent writers. This danger is the chief reason as- 

 signed for the more obscure coloring of the female 

 among so many species. Now it would seem that the 

 dangers of the mother bird during incubation ought 

 to be far less than those of her more brilliantly col- 

 ored mate, flitting from tree to tree and advertising 

 his whereabouts by his calls and song, or absorbed 

 in procuring his food ; or than those of other females, 

 flying about exposed to the eye of every passing 

 hawk. The life of most wild creatures is like that 

 of a people engaged in war : enemies lurk on every 

 hand, and the danger to the sitting bird may be 

 compared in degree to that of the wife rocking the 

 cradle by her fireside; while her roving mate must 

 face perils equal to those of a soldier on a cam- 

 paign. The mother bird is generally well hidden, 

 and has nothing to do but to use her eyes and ears, 

 and she usually does this to good purpose. Indeed, 

 I believe the sitting bird is rarely destroyed. I 

 have never known it to happen, though this fact 

 72 



