2012 年 24 巻 1 号 p. 1-6
I reconsidered the sex determination technique of using white spots of the inner vanes on primaries in the Spotted Nutcracker Nucifraga caryocatactes japonica. Thirty-two stuffed specimens collected at Yamashina Institute for Ornithology were examined. My results indicate that the existence of the white spot is unsuitable for use in sex determination. There were no significant differences between juvenile males and females in length of the longer axis of the white spot on primaries, or in length of the axis of the white spot on the 4th primary.