Using bird banding and recovery to study the migration of Black-necked Cranes ( Grus nigricollis ) in China

Abstract

In this present study, by reorganizing and classifying the bird banding and recovery records from 1985 to 2012, we discussed the current research status of the migrations of Black-necked Cranes (Grus nigricollis) in China. The results showed that 94 Black-necked Cranes in total were banded and 13 among them were also attached with satellite transmitters. Whereas, only 66 counts were recovered, i.e., 27 or 28 birds (same color ring combinations were used on two individuals repeatedly, but were recovered at different places), indicating a recovery rate of 28.72% or 29.79%, while, most of the recovery (63 counts, 95.45%) happened in wintering sites. Data of banding showed that Black-necked Cranes hit their sexual maturity at the age≥5 years, and the morphological indexes of the sub-adults are all smaller than those of the adults. After being banded, the average life span of banded individuals was 40±40 months (n=26, 1-161 months). Moreover, the recovery records indicate three migration routes of Black-necked Cranes: (1) the eastern flyway: from the Greater Ruoergai wetland area (breeding ground) of Sichuan and Gansu Provinces to northeastern Yunnan and northwestern Guizhou Provinces; (2) the central flyway: from the Longbaotan Nature Reserve of Qinghai Province (breeding ground, several other breeding sites along this route are located in northwest Sichuan Province) to the Napahai Natural Reserve, Yunnan Province (wintering ground); (3) from the vast area of northwestern Qinghai, Xinjiang, and northern Tibet (breeding ground) to the Yarlung Zangbo valley, southcentral Tibet and Bhutan. Our findings provide useful information to the relevant conservation and research facilities and institutes upon the banding, recovery and protection of the Black-necked Cranes. We recommend carrying out bird banding at breeding sites, while intensifying banding recovery and observation at wintering sites. Moreover, to establish long-term and stable information platforms and facilitate communication, it is urgent and necessary to standarize the banding and morphology measuring systems.