関伸一, 所崎聡, 溝口文男, 高木慎介, 仲村昇, ファーガス・クリスタル (2011) トカラ列島の鳥類相, 森林総合研究所研究報告 10: 183-229.
Shin-Ichi Seki, Satoshi Tokorozaki, Fumio Mizoguchi, Shinsuke Takagi, Noboru Nakamura, Fergus Crystal (2011) Avifauna of the Tokara Islands, northern Ryukyu Archipelago. Bulletin of the Forestry and Forest Products Research Institute 10:183-229. <PDF> (外部リンク external link)
要旨：琉球列島北部のトカラ列島は、屋久島と奄美大島の間に位置する地域であり、火山活動に由来す る 12 の島とそれに付属する岩礁が約 160km にわたって連なっている。トカラ列島における鳥類記 録を、1997 ~ 2010 年の現地調査、1892 ~ 2011 年の観察記録についての既存の文献とデータベー スの調査および聞き取り調査から集約し、種および島ごとに記録頻度の季節的変化を明らかにした。 トカラ列島における記録種数は 318 種で、島ごとの記録種数は最も面積の小さい上ノ根島の 9 種 から、面積が最大で最大標高も高い中之島の 257 種まで大きく異なっていた。このうち、営巣や巣 立ち雛の観察記録により繁殖が確認されたのは 31 種で、カラスバト Columba janthina、アカヒゲ Erithacus komadori、アカコッコ Turdus celaenops、イイジマムシクイ Phylloscopus ijimae など、分 布が限定的で保全の必要性が高い種が含まれていた。トカラ列島の繁殖種を、隣接する屋久島およ び奄美大島の繁殖種と比較すると、3 地域の中ではトカラ列島にのみ繁殖するものが 10 種と少な からず存在することから、トカラ列島の繁殖鳥類群集が単に面積や標高、種の供給源となりうる島 からの距離などにより制約されているだけではなく、トカラ列島独自の地史的背景の影響を受けて 形成された可能性があると考えられた。繁殖が示唆されなかった種の多くでは春期および秋期の渡 りの時期の記録頻度が高いが、冬期を通して記録されるものも 37 種あった。その中には、九州本 土では冬期の記録が希な種も含まれており、越冬地としてのこの地域の位置づけについては今後の 検討が必要であると考えられた。
Abstract: The Tokara Islands are a chain of 12 volcanic islands, located in the northern part of the Ryukyu Archipelago, stretching for 160 km between Yaku-shima (60 km to the north of the chain) and Amami O-shima (60 km to the south). The seasonal and spatial variation of avian records of this area was investigated, based on original observations recorded during the period 1997-2010, and also on existing records from the period 1892-2011, obtained by reviewing relevant literature and conducting interviews with birdwatchers active in the area. A total of 318 species was recorded, although the number of recorded species on each island differed widely from 9 species on the smallest island, Kaminone-jima, to 257 species on the largest and highest, Nakano-shima. Nesting pairs or young fledglings were observed in 31 species, including species of conservation concern like Japanese wood pigeon Columba janthina, Ryukyu robin Erithacus komadori, Izu thrush Turdus celaenops and Ijima's leaf warbler Phylloscopus ijimae. Among these breeeding species, 10 occur neither as breeders on Yaku-shima nor on Amami O-shima, suggesting the breeding bird community of Tokara has been formed under the effects of an unique geological history of the area, as well as historical immigrations from nearby source populations, including movement following local extinctions. The majority of non-breeding species was thought to consist of passage or accidental visitors, but 37 non-breeding species were recorded through the winter, including three species that are rare during winter on Kyushu main island to the north. Winter surveys have so far been few, and further research is needed to fully assess the wintering bird community in the Tokara Islands.
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関伸一 (2012) 自動撮影カメラとタイマー付録音機で記録されたトカラ列島の無人島群における鳥類相, Bird Research 8: A35-A48.
Shin-Ichi Seki (2012) Use of automatic photo and sound recording systems for avian inventory collections on three uninhabited islands located in the Tokara Islands, Japan. Bird Research 8: A35-A48. <extarnal links to Full text> (全文への外部リンク)
要旨：トカラ列島の３つの無人島（臥蛇島，上ノ根島，横当島）に上陸して直接観察を行なうとともに，森林内に自動記録装置（赤外線センサー式自動撮影カメラとタイマー機能付録音機）を１年以上にわたり設置して鳥類相を調査した．３島で記録された種数はそれぞれ40 種，30 種，28 種であったが，繁殖の可能性が示唆された種は 13 種，９種，８種であった．直接観察でのみ記録されたのは海鳥類やサギ科など森林を利用することが稀な種であった．また，いずれの島でも自動記録装置でのみ記録された種が約３分の１を占め，渡りの途中で一時的に滞在したり，越冬したりする渡り鳥で，上陸調査の実施可能な時期には観察しにくい種が多く含まれた．森林性で繁殖していると推測された種は複数の手法で共通して記録されることが多かったが，繁殖の可能性を判断する根拠となったのは主に録音機による繁殖期の連続的なさえずりの記録であった．自動記録装置は，動作安定性に課題が残されてはいるが，遠隔地では非常に効果的な調査手法であることが明らかになった．
Abstract: Data for avian inventories were collected from three uninhabited islands in the Tokara Islands, which are locations with difficult access for research. I used three methods of identification for birds on the islands: 1) direct observation during a few hours on each island during one summer season, 2) infrared-triggered cameras, and 3) timer programmed sound recording systems. Remote systems both had more than a year of battery life, and were installed in forest habitat. The total number of species recorded was 40 on Gaja Island, 30 on Kaminone Island, and 28 on Yokoate Island. The number of species which were inferred to be breeding on the islands were 13, 9, and 8, respectively. Sea birds and herons seldom used the forest habitat, and they were recorded only by direct observation. The avian species whose data were recorded only by the automatic recording systems, which were approximately one-third of the total number of species on any of the 3 islands, were mainly migratory species that wintered or passed through those areas on migration. Data for most of the forest species that were considered as breeding on these islands were repeatedly recorded by several different methods. Only the sound recordings provided continuous records of the presence of singing individuals throughout the breeding season, which gives us a reliable basis to identify the breeding species. Automatic photo and sound recording systems still have problems regarding endurance in the field; nevertheless, they are powerful tools for avian inventory data collection at remote sites.
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