32 GRAMINIVORyE. 



times requires to a wonderful degree at that time) to protect 

 them. Whether it be that instinct leads the female to hus- 

 band her heat for the purpose of hatching her eggs, or simply 

 that the thinning of the under plumage which takes place at 

 that time, and is the more conspicuous the more closely that 

 the bird sits, it is certain that the female of most birds avoids 

 the sun, and that all cover their eggs from the light during 

 the period of incubation. 



One can understand why the eggs should be covered, in- 

 asmuch as the germs of life, whether animal or vegetable, do 

 not perform their first action unless in the dark, or at least 

 in the shade. The sunbeams bring all living things to what 

 may be considered as their highest state of development and 

 perfection ; but it is all too powerful for the first or rudi- 

 mental stages ; and if life continues in what we are accus- 

 tomed to call a rudimental state, as in an earth-worm, an 

 oyster, or the moss which grows on the walls of ruins, the 

 clear and full light of day is too much for it. 



In the female bird there is thus an avoiding of the solar 

 influence as well as a want of excitability by it, and the one 

 of these may be the cause of the other ; and the two together, 

 though their effect would at first seem to take the other way, 

 show why the female should be the first to follow the sun in 

 his southward destination in the autumn. If a bird is perched 

 on a bush or stump that rises above the snow, the rays of the 

 slanting sun beat more ardently upon it than if they came 

 perpendicularly, while it perched on the succulent leaf of a 

 tropical plant. They are augmented by reflection from the 

 snow, and they strike the bird lower dpwn, and not so much 

 on the back, which from its gloss is the best calculated for 

 deflecting off the heat. The hideling bird, on the other hand, 

 would necessarily be subject to the excess of cold that pre- 

 vails in the shade. 



Besides, the plumage of motion is not so much worn in 



