THE VOICE OF THE DESERT 



32 



in size but carefully nursed by the owner of a rather large 

 house. The robin was digging for worms for all the world 

 as though he were on a New England lawn and any 

 worms he found had been introduced by man. No doubt 

 if large estates with artificially sustained lawns and trees 

 were more numerous and closer together than they are, 

 then the robins would move in. 



Still other creatures range naturally over vast and vastly 

 different areas simply because the few things indispensa- 

 ble to them are found everywhere, even in desert areas. 

 Not too long ago, for instance, a neighbor brought me a 

 large bat which had fallen into his swimming pool. Neigh- 

 bors are very generous with such gifts once they know that 

 you are willing to take the responsibility for them, and this 

 one I was glad to get. He rested for a while hanging upside 

 down in a cardboard box and then flew away, apparently 

 none the worse for his experience. But what interested me 

 particularly was the fact that, though I had never before 

 seen out here this particular sort of bat close enough to 

 recognize him, the white-tipped fur of his back was enough 

 to identify him as the hoary bat which is found all over 

 the United States except for the southern tip of Florida, 

 and which ranges well northward into Canada. Like our 

 other native bats, he is dependent upon flying insects for 

 food and that means that he must either hibernate in win- 

 ter or fly south to some place where insects are on the wing 

 the year around. But grant the hoary bat his necessary 

 food, and it appears that mountains, valleys, plains and 

 even deserts are all one to him. 



Ecologists like to "explain" the survival of a particular 

 animal or plant by noting its various "fitnesses." One crea- 

 ture, so they say, is peculiarly adapted to the temperature 



