162 PROBLEMS OF BIRD LIFE. 



trees. Who would expect to find a sage cock away from 

 sage brush ? or a spruce partridge (Canada grouse) outside of 

 the spruce forests ? It may not be chance alone that makes 

 the pine warbler haunt the pitch-pine country, and the blue 

 yellow-backed warbler always seek the neighborhood of the 

 hanging usnea, or swamp-moss. All these are facts of distri- 

 bution, and it is part of the good naturalist's work to observe 

 whether certain birds and plants always are found together. 



The study of distribution needs long training and wide 

 observation to be of any great worth, but a beginner may do 

 several things that will have a scientific value. One of the 

 simplest is to make a list of all the birds found within certain 

 limits; another is to notice carefully the kind of locations 

 preferred by each bird, whether open hard-wood, soft-wood, 

 thickets, brook-sides, meadows, and the like ; while a third is 

 to explore carefully some hill or mountain near home, with 

 the aid of a map, marking every hundred feet in elevation, 

 and to note carefully the elevations at which every kind of bird 

 and flower is seen, together with the slope of the hill, north, 

 east, south, or west, on which they are seen. By such explora- 

 tions, year after year, over any mountain, noting its zones and 

 the trees, plants, birds, and insects, the exposure to sun, the 

 amount of rain received, the character of the rock beneath, and 

 always the elevation, a patient observer could accomplish 

 much. But studies of this kind require more time and pains- 

 taking observation than most amateur naturalists are able to 

 spend. 



