202 ASIMAL LI hi-: IS Till: YOSEMITE 



The coiulnct of the California Gray S(iiiirrel in cuttinpr down the frreen 

 cones of the two important lumber trees, yellow and sugar pine, has been 

 commented upon adversely by foresters. The claim is made that the 

 squirrels consume so much of the seed that not enough is left for natural 

 reforestation. This point, so far as we know, has not been thoroufrhly 

 tested by experimentation ; the issue now stands between the judprment 

 of the forester on one hand, and that of the naturalist on the other. We 

 do know that many other factors, such as parasitism of the grrowing trees 

 by mistletoe or funjrus, destruction by fire started by lifrhtninpr or by 

 human agency, and killing of young growth by grazing, ojierate to limit 

 the numbers of the trees. And of the seeds which remain in cones on 

 the tree, a very considerable percentage is attacked by certain insects whose 

 young subsist on the embryo plant. The squirrels thus comprise but one 

 factor out of many ; attention is likely to be focused upon their work 

 because of its conspicuousness ; it is carried on in the open. Other agencies 

 fully as significant operate in an unobtrusive manner, and their importance 

 is thus likely to be underestimated. 



It is our opinion that in most places where natural conditions still 

 obtain, the necessary reseeding progresses as fast as is possible anyway, 

 and that the activities of the squirrels do not retard the regeneration of 

 the forest. Where man has interfered by logging off much of the timber 

 or by close grazing, the case may be different. 



One resident at Snyder Gulch stated to us that he believed tliat Gray 

 Squirrels indirectly do damage to sugar pines by leaving lieaps of cone 

 scales at the bases of trees when shucking out seeds. When a forest fire 

 sweeps over the country these piles take fire easily and start 'burns' at the 

 bases of the trees. As bearing on this contention we noted many sugar 

 pine trees with kitchen middens at their bases, and many trees showed 

 basal burns which may have been made in the manner indicated. At Hazel 

 Green there were heaps of scales about several oak trees, and at one par- 

 ticular tree there was a kitchen midden fully 18 inches high within the 

 hollowed base of the tree. 



The California Gray Scpiirrel, so far as known, rears but one brood 

 of young each year, and this is brought off during the early summer 

 months. None of the female squirrels which we obtained contained 

 embryos ; but litters elsewhere are known to range from 2 to 4. By mid- 

 summer the young animals are beginning to api)ear abroad, being then, 

 on the average, aboul lialf llie size of adults. 



The Gray S(juirrel poi)ulafion is aff'ected by a number of factors. Birds 

 of prey capture a certain percentage of the animals; some young are killed 

 by falling out of the nest ; other young animals are caught by dogs, and 

 in wild country prol)al)ly also liy native carnivores; disease greatly reduces 



