26 BIRDS OF THE ROCKIES 



and New England States than that of the Colorado 

 region. 



Perhaps the reason is largely, if not chiefly, physiolog- 

 ical. Evidently there are birds that flourish best in a 

 rai'e, dry atmosphere, while others naturally thrive in an 

 atmosphere that is denser and more humid. The same 

 is true of people. Many persons find the climate of 

 Colorado especially adapted to their needs ; indeed, to 

 certain classes of invalids it is a veritable sanitarium. 

 Others soon learn that it is detrimental to their health. 

 Mayhap the same laws obtain in the bird realm. 



The altitude of my home is eight hundred and eighty 

 feet above sea-level ; that of Denver, Colorado, six 

 thousand one hundred and sixty, making a difference of 

 over five thousand feet, which may account for the 

 absence of many eastern avian forms in the more elevated 

 districts. Some day the dissector of birds may find a 

 real difference in the physiological structure of the 

 eastern and western meadow-larks. If so, it is to be 

 hoped he will at once publish his discoveries for the 

 satisfaction of all lovers of birds. 



If one had time and opportunity, some intensely in- 

 teresting experiments might be tried. Suppose an 

 eastern blue jay should be carried to the top of Pike's 

 Peak, or Gray's, and then set free, how would he fare ? 

 Would the muscles and tendons of his wings have suffi- 

 cient strength to bear him up in the rarefied atmos- 



