INTRODUCTION 



spent in trees may be any color. The latter have little need 

 of protective colors, for the leaves screen them from above, 

 and, viewed from below, even brightly colored birds like 

 our Scarlet Tanager are less conspicuous than one would 

 think, owing to the kaleidoscopic effect produced by the 

 green leaves, the patches of blue sky and spots of yellow 

 where the sun's rays filter through the openings. 



Birds whose plumages are in harmony with their surround 

 ings often trust to this fact for avoiding detection. The 

 Green Heron and Bittern often allow a person to pass within 

 a few feet of them as they stand statue-like beside a few 

 rushes, many doubtless remaining unseen. Sparrows sit 

 upon their eggs in little grass nests on the ground until there 

 is danger of their being trod upon, before they take wing, 

 and the Woodcock is so sure of the efficacy of her plumage as 

 a protection that she will sometimes allow one to touch 

 her. 



Migration of Birds. — Twice each year most birds per- 

 form their wonderful migratory feats. It seems almost 

 beyond belief that tiny birds can start from their home site 

 here, travel several thousand miles across water and land to 

 northern South America, spend several months there and 

 then, with nothing but their memory and probably some 

 landmarks to guide them, find their way back to the exact 

 place from which they started. A person could not do it; 

 in fact many would become hopelessly lost in a piece of woods 

 a mile across. Birds have a keen sense of direction and, 

 traveling at high elevations as they do, they are able to pick 

 up familiar landmarks far ahead. Birds also have very acute 

 hearing and keen sight, which qualifications enable young and 

 less e.xperienced birds to follow the correct course by sound 

 and sight of the older ones. Doubtless you have noticed that 

 migrating small birds are calling to one another every few 

 minutes, probably for the very purpose of keeping in touch 

 with the ones that do not know the way. 



Migration, first performed to escape severe cold or because 

 of lack of food, has become a fixed habit with those species 

 that do regularly migrate. Many of them, long before it is 



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