Monitoring population dynamics of the migratory Red-crowned Crane (Grus japonensis) at Shuangtaihekou National Nature Reserve, northeastern China, from 1991 to 2012

We studied migratory Red-crowned cranes from 1991-2012 in order to track population dynamics and trends for these cranes over time at Shuangtaihekou, northeastern China. Our results show that the earliest arrival date of the Red-crowned Crane (Grus japonensis) was usually around 1 March in the spring and the latest departure date of the cranes around 8 November. The peak period for the number of cranes observed in the spring was 10-20 March over these 22 years. The staging period in the spring is about 25 days. Comparing the highest number of Red-crowned cranes observed in the spring, the migratory population was around 400 birds in the 1990s, then, increased to over 800 birds in 2000. For a short while, the population maintained itself around 600-800 birds. After that, the population started to decline, until during the most recent years, we observed around 400 birds at peak times of each season. Our results match a similar population change pattern observed in the wintering area for a western population, which has been declining since 2000. There is an urgent need to reinforce protection and management, as well as to maintain and improve the quality of their habitats.