NORTH AMERICA AND THE WEST INDIES 43 



(Pinus ponder osa) is found. It is largely dependent on this 

 tree for food and shelter as are its relatives of the Abert's 

 squirrel type, which, wherever they occur, "are rarely or never 

 seen beyond the local range of this tree. On the Kaibab 

 Plateau the altitudinal range is mainly from 7,000 to 8,500 

 feet" (Goldman, 1928). Major Goldman (1928) writes: 

 "Yellow pines are rarely hollow and I have never seen one of 

 these squirrels enter a hole. Dome-shaped nests, about 2 feet 

 in diameter, made of cut pine branches, are usually well con- 

 cealed among crowded limbs in the upper part of a tree. Like 

 most squirrels, the white-tail is most active during the early 

 morning and late afternoon, but may be found abroad at any 

 time of day. Practically nothing seems to be known of its 

 breeding habits." Although it depends partly for food upon 

 the seeds of the yellow pine, which it extracts by gnawing away 

 the scales, this supply is more or less precarious in years when 

 the crop is poor. Its main reliance is therefore the cambium 

 beneath the bark of the newer twigs of the yellow pine, which 

 provides an unfailing food supply. "In feeding, the leaf- 

 bearing branch tip is commonly severed and allowed to drop 

 to the ground. A subterminal section of tender stem 2 to 4 

 inches in length is cut off, scaled, and when the cambium sought 

 as food has been neatly removed, the peeled wood remaining 

 is also dropped ... In summer, however, they evidently 

 indulge in a more varied diet. Much time is spent in foraging 

 upon the ground and I have at various times observed them 

 feeding upon mushrooms and other funguses, and they doubt- 

 less eat many other things. " 



Although it is known that these squirrels are occasionally 

 taken by hawks, Major Goldman believes that their numbers 

 are no more seriously affected by these enemies than are those 

 of other forms of Abert's squirrel. "The destruction of much 

 ground cover through overbrowsing by deer may, however, 

 expose the squirrels to some additional danger from hawks. 

 Squirrels everywhere vary in numbers from year to year owing 

 to causes imperfectly understood, but at present there seems 

 to be no great danger of the extinction of the white-tail. These 

 beautiful squirrels are objects of great interest to tourists along 

 the Grand Canyon highway that bisects the Kaibab plateau, 

 and efforts should be made to establish them in other yellow 

 pine forested areas. " He adds the caution that care should be 



