The distributions and seasonal changes in the number of water birds and raptors in the coastal area of Osaka Bay

Abstract

010 年９月〜 2013 年９月に、大阪湾岸 40 ヶ所の水鳥と猛禽類の個体数を毎月調査した。水鳥 66 種と猛禽類 6 種が記 録され、多くの水鳥は冬期に多かった。冬期のカモ類、オオバン、カンムリカイツブリ、ユリカモメ、カモメが湾奥部に多い一方で、 冬期のウミネコとオオセグロカモメは淡路島から湾口部に多く記録された。湾奥部のウミネコは夏期には多いが、冬期は姿を消 した。ユリカモメは、2011 年と 2012 年の３月頃に明石海峡周辺で増加した。The number of individuals of water birds and raptors was counted in 40 study sites in the coastal area of Osaka Bay, monthly from September 2010 to September 2013. Sixty-six species of water birds and 6 species of raptors were recorded. Most water birds were abundant in winter. Ducks, Coots, Great Crested Grebes, Black-headed Gulls and Common Gulls were abundant in the inner area of Osaka Bay. Although, Japanese Gulls and Slaty-backed Gulls were mainly distributed in the mouth of Osaka Bay in winter. In the inner area, Japanese Gulls were abundant in summer, but disappeared in winter. Black-headed Gulls increased around Akashi Strait in March in 2011 and 2012.departmental bulletin pape