著者

倉沢 康大 平田 和彦

出版者

特定非営利活動法人バードリサーチ

雑誌

Bird Research (ISSN:18801587)

巻号頁・発行日

vol.17, pp.A31-A44, 2021 (Released:2021-08-17)

参考文献数

52

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津軽海峡における海鳥の密度とその季節変化を明らかにするために,2006-2010年に津軽海峡で,函館(北海道)と大間(青森県)を結ぶ旅客フェリーからの海上センサスを行なった.周年にわたる計151回の調査の結果,11科51種の海鳥が記録された.渡り途中のミズナギドリ科(ハシボソミズナギドリ,ハイイロミズナギドリ)やアカエリヒレアシシギが飛来する4-5月に海鳥の密度が最も高かった.11-12月には種数が最も多くなり,越冬地への南下中と考えられるカモメ科やウミスズメ科が多く記録された.本研究により,津軽海峡は沿岸性から外洋性まで多様な海鳥が生息し,種によって本海域を利用する時期や密度が異なることが分かった.

著者

倉沢 康大 安部 亮佑 西沢 文吾

出版者

公益財団法人 山階鳥類研究所

雑誌

山階鳥類学雑誌 (ISSN:13485032)

巻号頁・発行日

vol.52, no.2, pp.133-137, 2020-12-15 (Released:2020-12-16)

参考文献数

12

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On September 16, 2009 and July 7, 2018 we observed six Wilson's Storm-petrels Oceanites oceanicus on six occasions in the Northwest Pacific off Hokkaido. These are first records for Hokkaido and the northernmost records in Japan.

著者

西沢 文吾 倉沢 康大 山崎 彩

出版者

公益財団法人 山階鳥類研究所

雑誌

山階鳥類学雑誌 (ISSN:13485032)

巻号頁・発行日

vol.51, no.2, pp.105-115, 2019-12-15 (Released:2019-12-15)

参考文献数

41

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The Common Starling Sturnus vulgaris is a winter visitor to Japan, with more records in the western region. In Hokkaido, this species is known as an accidental visitor, and some reports suggest that the number of observations recorded in the Sapporo region have recently increased. In this study, we first reported our observations of the starling in Oshima Peninsula, southern Hokkaido, where this species had not been previously recorded. We then collected published observation records from 1987, when the first starling was recorded in Hokkaido, until 2018. From these records we examined the distribution of observations of the starling and assessed whether the number of them flying to Hokkaido has increased during this period. The birds were widely observed in Hokkaido, with the number of records occurring more frequently in the Sapporo, Ishikari and Okhotsk regions. The number of observation records was high both in spring (April) and fall (October), suggesting that the birds might visit Hokkaido during their migration. The annual number of observation records showed an increasing trend, which occurred every year from 2004. In addition, the number of birds per observation seemed to increase in recent years, but with high interannual variability. Therefore, careful attention should be paid to the changes in the number of starlings and their distribution throughout Japan, including Hokkaido.

著者

倉沢 康大 本田 聡 綿貫 豊

出版者

日本鳥学会

雑誌

日本鳥学会誌 (ISSN:0913400X)

巻号頁・発行日

vol.60, no.2, pp.216-227, 2011 (Released:2011-10-26)

参考文献数

44

被引用文献数

4 6

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A survey of the at-sea distributions of 1) planktivorous Short-tailed Shearwater Puffinus tenuirostris, migrating to their northern summering area and 2) piscivorous Rhinoceros Auklet Cerorhinca monocerata, breeding in the northern Sea of Japan off Hokkaido, was carried out by ship, from 16 to 28 May 2008. Avian censuses were combined with: acoustic surveys aimed at measuring prey density, and sea surface temperature (SST) surveys. Surface Chlorophyll a distribution was obtained using satellite imagery. The density of shearwaters was correlated positively with 200 kHz SA (the index of density of zooplankton including krill) at the 10 km scale, and 200 kHz SA was correlated negatively both with SST and Chlorophyll a. However, shearwater densities were not correlated significantly with SST and Chlorophyll a. The result suggest that migrating shearwaters may be able to find patches of krill in cold water. In contrast, the density of Rhinoceros Auklets was not correlated with 38 kHz SA (the index of pelagic fish density) or 200 kHz SA at any scale.

著者

倉沢 康大 板橋 豊 山本 麻希 綿貫 豊

出版者

日本鳥学会

雑誌

日本鳥学会誌 (ISSN:0913400X)

巻号頁・発行日

vol.61, no.1, pp.137-141, 2012 (Released:2012-04-27)

参考文献数

26

被引用文献数

2 6

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繁殖地を離れて1週間にもおよぶロングトリップ中にミズナギドリ類は餌の大部分を消化・吸収し,吸収しづらいトリアシルグリセロール(TAG)やワックスエステルを胃油として胃に蓄積する.胃油のもととなる餌生物を特定するため,胃油中のTAGの脂肪酸組成を新潟県粟島で育雛中のオオミズナギドリにおいて分析し,潜在的な餌の脂肪酸組成と比較した.胃油の脂肪酸組成は,カタクチイワシあるいはサンマに似ていたが,他の外洋性の生物を食べた可能性も完全には否定できない.この2種だけを食べたと仮定すると,その比率はオイルベースでカタクチイワシが77%,サンマが24%と推定された.