Red-crowned cranes are among the world's rarest birds and are primarily white with a patch of red bare skin on the crown. They let out sonorous calls and are often seen in wetlands and among reeds. In spring they usually breed in Heilongjiang province with the breeding season from April to June. Red-crowned cranes are monogamous and its lifespan is around 50 to 60 years, hence the name Xian He (crane of the immortals). The species can be found in northeastern China, eastern Mongolia, east of the Wusuli River in Russia, North and South Korea and Hokkaido in Japan.