Sex bias in a wintering population of Dunlin Calidris alpina in central Taiwan

作者：Yang Dzung Yun; Chiang Chungyu; Hsu Yu Cheng^*

来源：Forktail, 2012, (28): 67-70.

The sexes of many migratory shorebird species differ timing and distance of their migrations, but this phenomenon has been little studied for birds in the East Asian-Australasian Flyway (EAAF). Using molecular sexing techniques (but also taking morphometric data), we compared the sex ratio of Dunlin Calidris alpina sampled on the west coast of Taiwan between September 2007 and May 2008. We found an overall sex bias (59.2%) toward females, including juveniles. A discriminant function deduced from three morphological measurements correctly identified 89.0% of Dunlin, but performed better in identifying males than females. Since Taiwan is at the southern end of the Dunlin's East Asian winter range, our results support the 'arrival-time' hypothesis whereby the sex that arrives earlier on the breeding grounds winters closer to them. To maintain stable populations, conservation must take account of this differential use of wintering grounds by the two sexes.

• 出版日期2012-8
• 单位东华大学