The Birds’ Calendar 
one dropped out of the air, leaving the forest 
to the solemn stillness of the night, there 
sounded last of all, out of the gathering 
gloom, the distant, sad refrain of the pewee, 
like a mournful ‘finis’’ to the day. It 
seemed the essence of darkness transmuted 
into song. , 
It is interesting to note how every physical 
condition of the globe peculiarly fosters its own 
forms of life. Heat and cold, moist and dry, 
light and darkness, are each promotive of its 
own species, vegetable and animal, for which 
any other condition would be injurious or fatal. 
The edelweiss flourishes in the arctic clefts of 
the Alps, the coral polyp deep beneath the ocean, 
the soil itself teems with life; and while in gen- 
eral sunlight is so essential to healthful vitality, 
yet darkness hath its charms as well, and vege- 
tation sometimes reserves its blossoming for the 
night, while the setting sun is the signal for 
many a beast and bird, crawling reptile and 
hovering insect, to awake and resume its daily 
activity. 
While birds are chiefly diurnal, a few, like 
the owls, are nocturnal, and a few are crepus- 
184 
