本州中部の高山帯に生息するカラスの分布と個体数

概要

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The distribution and population size of crows inhabiting the alpine zone (above 2,400 m asl), central Honshu, were studied on the basis of published literature, a 2005 questionnaire survey and interviews of the owners of mountain huts. Crows were present at 45 of the 62 high mountains surveyed. The distribution was increased because the crows occurred at 11 mountains before the 1970s. There were 1-4 individuals at each mountain and they were usually observed from May to October when the mountain huts opened. We estimated a total of 156 individuals at the 45 high mountains: most were Jungle Crows (Corvus macrorhynchos). The crows scavenged the food scraps dumped by mountain climbers. Moreover, at some mountains they ate the eggs and chicks of the Rock Ptarmigan (Lagopus mutus), the Alpine Accentor (Prunella collaris), and the House Martin (Delichon urbica). Attention should be paid to the future distribution and diet of crows inhabiting the alpine zone.