Further comments on the ageing and sexing of the Red-flanked Bluetail

摘要

The recent increase in the numbers of Red-flanked Bluetails Tarsiger cyanurus reaching western Europe has led to discussions on published criteria for ageing and sexing of the species. Here, we present our observations of birds handled at Beidaihe Bird Observatory, in Hebei province, China, in spring 2011 and both spring and autumn 2012. This is supplemented by data from the bird observatories at Ottenby and Stora Fjaderagg (in Sweden) and by observations of Red-flanked Bluetails in the field in south-central Siberia, northeast China and Sweden.