渡り途中のハシボソミズナギドリと繁殖中のウトウの分布と餌密度 [in Japanese] Distribution of migrating Short-tailed Shearwater and breeding Rhinoceros Auklet and their prey in the northern Sea of Japan, Hokkaido in spring [in Japanese]
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A survey of the at-sea distributions of 1) planktivorous Short-tailed Shearwater <i>Puffinus tenuirostris,</i> migrating to their northern summering area and 2) piscivorous Rhinoceros Auklet <i>Cerorhinca monocerata,</i> 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 <i>Chlorophyll a</i> distribution was obtained using satellite imagery. The density of shearwaters was correlated positively with 200 kHz <i>S</i><sub><i>A</i></sub> (the index of density of zooplankton including krill) at the 10 km scale, and 200 kHz <i>S</i><sub><i>A</i></sub> was correlated negatively both with SST and <i>Chlorophyll a</i>. However, shearwater densities were not correlated significantly with SST and <i>Chlorophyll a</i>. 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 <i>S</i><sub><i>A</i></sub> (the index of pelagic fish density) or 200 kHz <i>S</i><sub><i>A</i></sub> at any scale.
- Japanese Journal of Ornithology
Japanese Journal of Ornithology 60(2), 216-227, 2011
The Ornithological Society of Japan