The Red-crowned Crane (Grus japonensis) is a globally endangered species. Although this species has received much attention by scientists, conservationists and the general public, the continental population of the Red-crowned Crane continues to face serious threats which affect not only its population dynamics but also its breeding and wintering habitats. Habitat loss and deterioration are the main causes of the decline of its population. With the massive loss of habitats in all parts of its range ― breeding, stopover and wintering grounds ― the cranes have been forced into crops and farmlands where cranes are more vulnerable to human activities, such as poisoning the cranes and conflicts with farmers. From our review of studies done over 30 years, the eastern flyway subpopulation has been stable or slightly increasing and the western flyway subpopulation of the Red-crowned Crane has sharply declined in recent years. The wintering population for the western flyway has declined from over 1100 to less than 500 birds. Not only is the size of the population reduced to less than 50%, but most recently the decline has occurred with frightening speed, by 50- 150 birds per winter. The current wintering range for the west flyway is only about 8% of its extent in the 1980s. Urgent actions for habitat protection, law enforcement and education need to stop the declining trend for this species.