Sika Deer (Cervus nippon) John Collins. Two species of deer take advantage of the island's interior forests and shrub habitats, the native white-tailed deer (Odocoileus virginianus) and the non-native sika deer (Cervus nippon), actually a diminutive species of oriental elk. Ongoing research is evaluating the ecological effects of sika deer on both native vegetation communities and other wildlife such as the white-tailed deer.