Zoological Studies

Vol. 57, 2018

(update: 2018.09.03; 10.15) 

Effectiveness of Morphological Sex Determination in the East Asian Barn Swallow (Hirundo rustica gutturalis) on Spring Migration

Hyun-Young Nam1,2, Seung-Yeon Lee1, Sook-Young Cho1, Chang-Yong Choi1,3,*, Se-Young Park1, Gi-Chang Bing1,4, Chang-uk Park1, Seul-Gi Seo1, and Yang-Mo Kim1


1Bird Research Center, National Park Research Institute, Korea National Park Service, Jeonnam 58863, Republic of Korea. E-mail: stern0223@gmail.com (Nam)
2School of Biological Sciences, Seoul National University, Seoul 08826, Republic of Korea
3National Instrumentation Center for Environmental Management, Seoul National University, Seoul 08826, Republic of Korea
4Natural History Research Office, National Science Museum, Daejeon 34143, Republic of Korea

(Received 3 October 2017; Accepted 30 July 2018; Communicated by Chih-Ming Hung)

Hyun-Young Nam, Seung-Yeon Lee, Sook-Young Cho, Chang-Yong Choi, Se-Young Park, Gi-Chang Bing, Chang-uk Park, Seul-Gi Seo, and Yang-Mo Kim (2018) Information on sexual dimorphism helps explain a species’ evolution in sexual selection and conservation issues such as sex-specific response in environmental changes. The Barn Swallow (Hirundo rustica) is a well-known sexually dimorphic species in which males have longer tail streamers than females. However, when compared with the European-African or American subspecies, little information is available on morphological sex determination in the East Asian subspecies H. r. gutturalis, especially outside the breeding season, when opportunities for molecular sexing are often limited and morphological clues may be the only ones available for sex determination. We collected morphological data on H. r. gutturalis during the northbound spring migration at a stopover site off the Korean coast. Two of eight measured variables - streamer length (the difference in length between the 5th and 6th rectrices; T6-T5) and length of the white patch on the outermost tail (6th rectrix; T6) - were selected as the best predictors for sex determination by stepwise discriminant analysis. Quadratic discriminant functions based on these variables showed that 92.4-93.5% of females and 82.9% of males were correctly classified. Our results provide baseline information that will benefit more accurate sex determination of the East Asian Barn Swallows, especially during the early months of a calendar year in non-breeding and stopover areas.

Key words: Barn Swallow, Discriminant function analysis, Hirundo rustica gutturalis, Sex determination, Sexual dimorphism.

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