Two forms of black-tailed deer or blacktail deer that occupy coastal temperate rainforests in the Pacific Northwest are subspecies of the mule deer (Odocoileus hemionus). They have sometimes been treated as a species, but virtually all recent authorities maintain they are subspecies.The Columbian black-tailed deer (Odocoileus hemionus columbianus) is found in western North America, from Northern California into the Pacific Northwest and coastal British Columbia.