During the summer season the food supply of some animals is greatly augmented and their numbers about development centers are increased thereby. In Yosemite Valley this is certainly the case with black bears and, very probably, with mule deer. When fall comes this artificial food is no longer available and the drain on the natural food becomes very heavy, with detrimental results to both forage and animals. Where man's presence influences one species adversely, the fact that it also keeps enemies of that species away is a compensating factor. But for species that thrive near civilization, the absence of the controlling predators increases the problem.
Mountain lions shun the valley.
Even if their numbers were normal for the park as a whole, they would not linger where there are so many people. Both wild cats and coyotes frequent the valley, but do not hunt too near the camps and buildings. The same is generally true of the larger hawks. Consequently man has not only favored the California ground squirrels with an excellent food supply, but he has protected them against their natural enemies until they have multiplied greatly. This is one instance where safe control measures applied to those particular areas would be actually beneficial to wild-life values.