Sexual dimorphism of Latham’s Snipe (Gallinago hardwickii)
Tatsuya Ura A B , Noriko Azuma A , Seiji Hayama A and Seigo Higashi AA Laboratory of Environmental Medicine and Informatics, Graduate School of Environmental Earth Science, Hokkaido University, Kita 10 Nishi 5, Kita-ku, Sapporo 060-0810, Japan.
B Corresponding author. Email: ura@wing-wbsj.or.jp
Emu 105(3) 259-262 https://doi.org/10.1071/MU04019
Submitted: 23 March 2004 Accepted: 15 August 2005 Published: 12 October 2005
Abstract
Latham’s Snipe has a characteristic and conspicuous display flight that includes power-diving and loud drumming sounds. However, the ecology of this Snipe has received little study, perhaps in part because the bird has been considered difficult to sex. We measured eight morphological traits and examined adult and juvenile birds to identify sexually dimorphic characteristics useful for sexing in the field. To confirm the sex determination, molecular sexing was also performed. Four traits in adults and juveniles showed marked differences between sexes, with males weighing less, having shorter bills and longer and more rectrices. A logistic regression model of two measurements, bill-length and number of rectrices, correctly allocated 81.9% of the sample birds to the correct sex. Sexual dimorphism in this Snipe may be a consequence of sexual selection on male agility while performing display flights.
Acknowledgments
We thank Dr O. Hasegawa for his valuable advice and help regarding molecular sexing; Tomatho Inc. for providing the study site; Messrs H. Ichikawa and M. Kato of the Botanic Garden of Hokkaido University for permitting us to measure the preserved specimens; and Ms Dwi Astuti for advising us about techniques for anatomical sexing. Many thanks also are due to Prof. Y. Fujimaki, Dr K. Edo, Dr T. Kikuchi, Mr T. Tomioka, and other staff members of the Lake Utonai Sanctuary Nature Center for their useful advice and assistance. The contributions of two anonymous referees are gratefully acknowledged. This work was financially supported in part by the Japan Society for the Promotion of Science (JSPS), Grant-in-Aid no. 17207003.
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