378 



SCIENCE 



[N. S. Vol. XL/TV. No. 1133 



dead trees for a livelihood. In these they find 

 food during the colder months of the year, 

 when the insects elsewhere are in great scar- 

 city. Here, too, they excavate their nesting 

 holes. Some of the squirrels and chipmunks 

 also seek shelter in dead or partially dead trees. 

 Even down timber is an essential factor in up- 

 holding the balance of animal life, for fallen 

 and decaying logs provide homes for wild rats 

 and mice of various kinds, and these in their 

 turn support many carnivorous birds and 

 mammals, such as hawks, owls, foxes and 

 martens. 



No more undergrowth should be destroyed 

 than is absolutely necessary. To many birds 

 and mammals thickets are protective havens 

 into which their enemies find it difficult to 

 penetrate. Moreover, the majority of the chap- 

 parral plants are berry-producers and give sus- 

 tenance to wild pigeons, mountain quail, robins 

 and thrushes, and to chipmunks and squirrels 

 — this, too, at the most critical time of the 

 year, when other kinds of food are scarce or 

 altogether wanting. The removal of such plant 

 growth will inevitably decrease the native ani- 

 mal life. If any change is to be made at all, 

 it would, indeed, seem preferable to increase 

 the number of indigenous berry-producing 

 plants, especially in the vicinity of camps and 

 buildings. This would compensate for the 

 shrubbery lost in constructing roads and 

 buildings, and would also serve to attract 

 berry-eating species to the points where they 

 might be seen by the largest number of people. 



It goes almost without saying that the ad- 

 ministration should strictly prohibit the hunt- 

 ing and trapping of any wild animals within 

 the park limits. A justifiable exception may 

 be made when specimens are required for sci- 

 entific purposes by authorized representatives 

 of public institutions, and it should be re- 

 marked in this connection that without a sci- 

 entific investigation of the animal life in the 

 parks, and an extensive collection of speci- 

 mens, no thorough understanding of the con- 

 ditions or of the practical problems they in- 

 volve is possible. But the visiting public 

 should be warned against injuring, and even 

 against teasing or annoying any of the mam- 



mals, against destroying lizards and snakes 

 (except the rattlesnake), and against disturb- 

 ing the nests of birds, or their young. In the 

 last instance a very slight disturbance will 

 often lead to subsequent destruction. The 

 principle underlying these suggestions is ap- 

 parent. The native complement of animal life 

 must everywhere be scrupulously guarded, 

 particularly along the most traveled roads and 

 paths, where the animals are likely to be ob- 

 served by the greatest number of visitors. It 

 is there that each individual animal is of 

 highest intrinsic value from an esthetic view- 

 point. 



As a rule predaceous animals should be left 

 unmolested and allowed to retain their primi- 

 tive relation to the rest of the fauna, even 

 though this may entail a considerable annual 

 levy on the animals forming their prey. We, 

 as naturalists, are convinced that the normal 

 rate of reproduction among the wild non-pre- 

 daceous species, such as mice and squirrels, has 

 adjusted itself to meet a certain annual draft 

 on their population by carnivorous enemies. 

 Another point worth emphasizing is that many 

 of the predatory animals, like the marten, the 

 fisher, the fox and the golden eagle, are them- 

 selves exceedingly interesting members of the 

 fauna, and as their number is already kept 

 within proper limits by the available food 

 supply, nothing is to be gained by reducing it 

 still further. Here again may be recognized 

 the special and intimate relations everywhere 

 existing among the various plants and ani- 

 mals. 



The rule that predaceous animals be safe- 

 guarded admits of occasional exceptions, ac- 

 cording to season, place and circumstance. 

 Coyotes and bob-cats, especially the latter, 

 when they are numerous, are likely to kill a 

 great many grouse, quail, rabbits and squir- 

 rels. Cooper and sharp-shinned hawks, and, to 

 a lesser extent, blue jays, are proven menaces 

 to small birds, and it might be advisable to re- 

 duce them in the neighborhood of camps and 

 much-traveled roads. Caution, however, 

 should be exercised in doing so, and no step 

 taken to diminish the numbers of any of these 

 predators, except on the best of grounds. 



