Frequent preserve visitors often encounter deer, although they will likely run away if you are too close. The range of black-tailed deer extends from southern California to Canada, although individuals’ home territories extend only a mile or so. Deer prefer habitat that includes tree cover — for shelter and safety — and open grasslands or chaparral for tasty shrubs with new leaves, although they will eat a wide variety of plants, including oaks and berries. They are a key prey species for mountain lions. After rising for decades, California’s deer populations have been declining due to habitat loss.