NORTH AMERICA AND THE WEST INDIES 269 



from Jackson Hole and Yellowstone Park . . . We now 

 have approximately 3,500 head on the ranges" (Cook, 1936, 

 p. 187). In Wyoming, Montana, and Idaho they have been 

 completely saved from extinction through adequate protective 

 measures. In 1932 there were, in national parks of the United 

 States, an estimated total of 15,420 and in national forests 

 over 96,800 (Phillips, 1935). 



In a recent survey of the elk situation, it is shown by Skinner 

 (1928) that in the Yellowstone region, for example, any ade- 

 quate plan for maintaining the elk population should consider 

 providing a sufficient food supply for winter as well as summer. 

 This seems to consist under natural conditions of "browse" 

 as well as grass, so that the hay supplied in recent years for the 

 Jackson Hole herd in winter is probably not an adequate 

 diet. He gives a partial list of food plants used from month 

 to month. Protection against unusually heavy snows and cold 

 is another problem, for when elk are forced out from Yellow- 

 stone Park into the surrounding low country in winter, thou- 

 sands are killed by hunters, without supervision or restraint. 

 There is the further problem of competition with bison herds 

 of the region for food, the depredations of coyotes, wolves, 

 and mountain lions, though these are less important. Finally 

 diseases, some of which may be introduced through domestic 

 stock, and parasites are as yet insufficiently known. Murie 

 (1930) has made a special study of winter losses among the 

 elk at Jackson Hole, Wyoming, and attributes a large portion 

 of them to necrobacillosis, the symptoms and general etiology 

 of which he describes and illustrates. The sharp awns of the 

 squirreltail grass, which produce lesions in the skin of mouth, 

 tongue, or throat and so afford entrance for the disease organ- 

 isms, seem to be a contributory factor in this. The elimination 

 of this grass, if that is possible, might aid in preventing the 

 trouble. All these problems are matters of importance in 

 maintaining the elk herds and increasingly demand careful 

 consideration. A beginning in this had already been made by 

 the U. S. Biological Survey, in concert with the Forest Service 

 and a program of management laid 30 years ago (see Graves 

 and Nelson, 1919). The present excellent condition of the 

 herds in Yellowstone Park reflects the wisdom of the policies 

 pursued. 



A decade ago, during prohibition days, a number of elk 



