| Titre : | The endangered Brown Shrike subspecies Lanius cristatus superciliosus has a male-biased sex ratio and only early arriving males are paired (2022) |
| Auteurs : | Haruka Mizumura, Auteur ; Kohei Kubota, Auteur ; Hiroyoshi Higuchi, Auteur |
| Type de document : | Article |
| Dans : | Bird Conservation International (32(1) March, 2022) |
| Article en page(s) : | 87-94 |
| Langues: | Anglais |
| Mots-clés: | arrival timing ; male-biased sex ratio ; migration ; shrike conservation |
| Résumé : | Along with many long-distance migrant passerine species in the East Asian-Australasian Flyway, the migratory Brown Shrike Lanius cristatus superciliosus has been sharply declining throughout its breeding range. Its breeding range in Japan shrank by 90.9% between the 1910s and 2010s. In contrast, the closely related but resident Bull-headed Shrike L. bucephalus bucephalus has been gradually declining but is still a common resident in Japan. To better understand the drastic decline of Brown Shrike, we compared the pairing success during three consecutive breeding seasons of these two species. About 60–70% of Brown Shrike males were unpaired, which was much higher than the percentage of unpaired male Bull-headed Shrike (c.0–20%). Brown Shrike males arriving later did not pair because the population’s sex proportion is heavily biased toward males. One of the factors of male-biased population of Brown Shrike may be female-biased mortality in wintering sites, or on the migratory journey, and tracking studies will be required to test this. |
| En ligne : | https://www.cambridge.org/core/journals/bird-conservation-international/article/endangered-brown-shrike-subspecies-lanius-cristatus-superciliosus-has-a-malebiased-sex-ratio-and-only-early-arriving-males-are-paired/23A6A3AA40E709AC3303E7772867DA3B |



