Six white-tailed deer and six sika deer were enclosed in a pasture for observation during an eight-year study in central texas. white-tailed deer are a native species to central texas, while sika deer are a nonnative species to central texas. white-tailed deer feed on flowering plants and the tips of trees and shrubs but do not eat grass. sika deer feed on flowering plants, the tips of trees and shrubs, and grass. all other grazing animals were kept out of the pasture during the study. the number of sika deer more than doubled after the eight years, while the population of white-tailed deer decreased by 50 percent. six white-tailed deer and six sika deer were enclosed in a pasture for observation during an eight-year study in central texas. white-tailed deer are a native species to central texas, while sika deer are a nonnative species to central texas. white-tailed deer feed on flowering plants and the tips of trees and shrubs but do not eat grass. sika deer feed on flowering plants, the tips of trees and shrubs, and grass. all other grazing animals were kept out of the pasture during the study. the number of sika deer more than doubled after the eight years, while the population of white-tailed deer decreased by 50 percent.