Rectification of Abnormal Migration Recorded in Hand-reared Red-crowned Cranes (Grus japonensis)

Abstract

Understanding the complexities of avian migration is important for ecological and conservation biological studies. While much progress has been made in studying relatively small-sized birds, migratory behavior of large and long-lived species such as cranes is not fully understood and experimentation on such species is difficult. In December 2015, four hand-reared Red-crowned Crane (Grus japonensis) subadults were found in northeast China, which is not the normal wintering ground for this species. Using GPS-GSM transmitters, migration performance of four hand-reared and three wild Red-crowned Cranes was monitored between 2015 and 2018. Wild individuals followed a north-south migration route along the east coast of China, while hand-reared cranes took an abnormal west-east migration route for the first two years. After reaching sexual maturity in 2017, one of the hand-reared individuals rectified its abnormal migration route and obtained a regular north-south migration route. Results indicate that it is critical to include experienced migrants in the releasing group to guarantee correct migration direction when implementing re-wilding projects in Red-crowned Cranes.