Avian Research (Jan 2022)
Autumn migration routes of fledgling Chinese Egrets (Egretta eulophotes) in Northeast China and their implications for conservation
Abstract
The Chinese Egret (Egretta eulophotes) is a globally threatened bird species living on the coast and islands of Liaoning, northeastern China, mainly in summer. To further protect the breeding population of Chinese Egrets, it is important to understand the current protection status of their distribution sites at pre-migration period and migration routes. Thirty-three individuals were tagged with satellite transmitters at Fantuo Island in Changhai and Xingren Island in Zhuanghe, Liaoning Province, northeastern China, in July of 2016, 2017, and 2018, to identify important distribution sites during the pre-migration period, as well as detailed migration routes. The results showed that coastal mudflats in Liaoning and the west coast of North Korea were important feeding and roosting sites for fledgling Chinese Egrets from August to September. The home range sizes in August were significantly larger than in September. The eastern coast from Shandong to Guangdong, as well as Taiwan, China, and Manila Bay and Galileo Islands in the Philippines, were important stopover sites during fall migration. Specifically, we found that the egrets’ autumn migration could be divided into four routes, i.e., sea-crossing migration (SCM), coastal migration (CM), inland migration (IM), and mixed migration (MM). The migration distance, timing, speed, and straightness of the four routes also differed. The SCM routes were the straightest, and had the fastest migration speed and shortest travel time, while the IM routes had the lowest straightness and speed, and the longest duration. Manila Bay and Bohol Island in the Philippines, the west coast of Tanintharyi in Myanmar, and the Zengwun River Estuary in Taiwan, China, were wintering sites. Our findings on the key distribution sites along pre-migration and fall migration routes, including some stopover sites, have important implications for the conservation of and global action plan development for the vulnerable Chinese Egret.
