広島県東広島市七ツ池におけるカモ類の出現記録 : 特に，希少種メジロガモ，トモエガモの出現及び3種の越夏や渡りの遅れについて

広島県東広島市に位置するため池「七ツ池」においてカモ類の出現調査を実施した。国内では希少なメジロガモAythya nyroca（Güldenstädt, 1770）が2022 年5 月に市内では初めて記録された。2005 年以降の本種の広島県内の出現記録も整理した。環境省レッドリストで絶滅危惧II 類に選定されているトモエガモAnas formosa Georgi, 1775 も同年2–3 月に記録された。オカヨシガモAnas strepera strepera Linnaeus, 1758，コガモ Anas crecca crecca Linnaeus, 1758，ホシハジロ Aythya ferina（Linnaeus, 1758）の越夏及びキンクロハジロAythya fuligula（Linnaeus, 1758）の北帰行の遅れなども同所で確認された。

The seasonal occurrence of wild ducks in the Nanatsu-ike Pond, Higashi-Hiroshima, Hiroshima Prefecture, Japan, was investigated from May 2021 to May 2022. Twelve species were recorded during this period. An adult male ferruginous duck, Aythya nyroca (Güldenstädt, 1770), a very rare stray bird in Japan, was found in March 2022. This is the first record of the species in Higashi-Hiroshima City. Recent records of its presence in Japan are compiled here. A male Baikal teal, Anas formosa Georgi, 1775, designated as a vulnerable species by the Japanese Ministry of Environment, was also recorded between February 20 and March 13, 2022. Gadwall Anas strepera strepera Linnaeus, 1758; common teal Anas crecca crecca Linnaeus, 1758; and common pochard Aythya ferina (Linnaeus, 1758) were frequently recorded during the winter and spring of 2022. However, some of them clearly oversummered in 2021 and 2022. A female tufted duck, Aythya fuligula (Linnaeus, 1758), was observed at the end of May 2021 and may have delayed returning to the breeding area.