47 strange forest 



peckers. In fact one species of the latter, the gilded flicker, 

 seldom nests in anything except a hole which it has ex- 

 cavated in the saguaro, and its range is almost coexten- 

 sive with that of the giant cactus. Moreover, this particular 

 bird insists upon digging a new home ever so often, leaving 

 abandoned dwellings to be used by quite a few other 

 species of nesting birds — by cactus wrens, elf owls and 

 others, even sometimes, as I have happened to observe, 

 by honeybees who have left their man-made hive. The 

 result of all this is that there are very few mature saguaros 

 which do not have from one to a dozen cavities in their 

 trunks. But the saguaro handles this situation very success- 

 fully. The wound inflicted by the flicker is quickly sealed 

 off by a layer of extraordinarily tough scar-tissue. Not 

 infrequently one finds among the bleached ribs of some 

 long dead saguaro a curious boot-shaped receptacle which 

 represents the lining of a flicker's nest. The Sonoran Desert 

 must be one of the few places in the world where one 

 may come home from a walk carrying a hole — and a very 

 dinrable one at that. 



For plants which grow only in one or more isolated and 

 very restricted areas the botanists have a word: "endemic." 

 Endemics contrast most sharply with "cosmopolitans" 

 which sometimes almost circle the globe, somewhat less 

 sharply with other species or genera which cover large 

 areas without being actually cosmopolitan. But there are 

 few species whose endemism is more striking than that of 

 the saguaro which is limited to this one small area. And 

 there are few if any endemics which are so striking a 

 feature of the one region where they are at home. 



Both cosmopolitanism and endemism present problems 



