CHAPTER XIX 



BIRDS, CONCLUDED. VARIOUSLY INVOLVED PRINCIPLES OF PROTECTIVE COL- 

 ORATION OF THE BIRDS OF TROPICAL FORESTS. WINTER BIRDS OF 

 THE SNOWY NORTH. CONCLUDING REMARKS ON BIRDS 



THE dim, brown underworld of tropical forests is tenanted by a race of 

 birds and beasts which show a wonderful uniformity in coloration and 

 degree of counter shading. The daylight in these solenm depths is diffuse 

 and weak; hence the animals which live in them are as a rule very slightly 

 shaded from dark to light, and many have pale-brown undersides. Brown 

 is their prevailing color, and there is one particular tone of rich chestnut-brown 

 which occurs almost unvaried on many hundred species. Such sameness of 

 coloration is remarkable; but it is in perfect keeping with the monotony of the 

 realm in which the creatures live. Almost nowhere else can one find such a wide- 

 ly extended prevalence, throughout the year, of a particular degree of light and 

 a few simple tones of color, as exists inside the shell of the great tropical forests. 

 On the outside of that shell everything is different. There, in the blazing 

 sunshine toward which the closely crowded trees and vines are ever struggling, 

 the victors heave their leafy heads, flashing and dancing with a thousand tints 

 of gold and green and sky-reflected blue — ^jeweled with gorgeous fruits and flow- 

 ers. In this gay realm of scintillating lights and colors live almost all the bril- 

 liant birds and butterflies, for which the tropics are famous; and they are as 

 closely fitted to their environment in colors and patterns as are their dull-brown 

 relatives of the somber shades below. The tropics are as rich in dull-colored 

 birds and butterflies as in bright ones; but the dull kinds are not often collected 

 and exported except by naturalists, and do not attract popular attention. 



The transition from the tree-top to the ground type, in habits and in col- 

 oration, is beautifully gradual and consistent. Blue— clear, skyey blue — 



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