Abstract. On 17th May 2009 an individual Brewster's Brown Booby Sula leucogaster brewsteri was observed and photographed, on Nakanokamishima Island, a breeding ground for six seabird species, including the related subspecies S. l. plotus. Diagnostic characteristics of the individual included a whitish head, cheeks and throat, becoming gradually pale brown on the neck. The coloration of the facial skin around the eyes was rich blue, which is characteristic of the male. The absence of dark mottles on the normally white area from the lower breast to belly, which constitute juvenile and immature stages, indicate that the individual was an adult. This is the first record of this subspecies from Japan.Key words: Brewster's Brown Booby, Brown Booby, Nakanokamishima Island, subspecies, Sula leucogaster brewsteri. ῏ῌῑῌῐ῍ ̮̮ Brewster's Brown Boobyῌ ῑῒῐΐῌ ῗῖῙῌ ̮̮ῌ Sula leucogaster brewsteri.

Abstract. The Brown Booby Sula leucogaster is divided into four subspecies and is distributed throughout the tropical and subtropical seas of the world. This species was believed to show little movement and low or no gene flow among populations, however, there exist several records of dispersal and breeding across the East Pacific Basin, both by S. l. plotus and S. l. brewsteri inhabiting the western and eastern sides, respectively. We observed a male of S. l. brewsteri visiting Nakanokamishima, Japan, which is one of the breeding sites of S. l. plotus in the West Pacific. Presumably, it was this same individual that was observed intermittently until 2014 and bred and produced offspring with a S. l. plotus female, adapting to the breeding schedule of the Nakanokamishima population from 2012 to 2014. Another male having a white head and neck was recorded at another location on the island since 2011. Although this male often courted a female, they have not yet formed a pair. These are the first records of S. l. brewsteri breeding behaviour in Japan and provide important ecological information regarding the process of pair formation and breeding at the breeding sites of other S. leucogaster subspecies.

2 東海大学 沖縄地域研究センター(〒907-1541 沖縄県八重山郡竹富町上原870-277) 3 正会員 (国研)防災科学技術研究所 水・土砂防災研究部門(〒305-0006 茨城県つくば市天王台3-1) 本研究の目的は，温暖化時に東京湾，伊勢湾および大阪湾に来襲すると予測される強大な台風に匹敵する 台風下の流速・波浪の実測データ取得である．そこで，地理的条件から強大な台風の来襲確率が高い沖縄 県西表島網取湾においてWavesADCPを用いた現地観測を実施した． その結果，最大瞬間風速46.5 m/sの台風1513号，54.1 m/sの台風1515号および44.9 m/sの台風1521号時の 流速・波浪データの取得に成功した．そして，最も大きな暴風をもたらした台風1515号下において，短時 間ではあるものの海面付近から底面に向かって流速が大きくなるなどの特徴を示した．

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