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一般研究成果リスト

Detail of Grant Awarded General Researches

Project

Research on the Ecology of the Mountain Hawk-eagle, an Endangered Species in the Tama River Basin (Tokyo Metropolitan Area)

General
Research
No.200
Principal
Investigator
Takashi Yamaguchi
Affiliation Mountain Hawk-eagle Ecology Research Team
Research
Summary

In the metropolitan Tokyo area, there have only been limited observations carried out on mountain hawk-eagles, and their precise population and propagation conditions were hardly understood. We have carried out an intense mountain hawk-eagle survey in FY2010 and FY2011 to find out their actual habitat distribution, propagation conditions, and nesting environment and to utilize the data obtained for their protection.


 


From the surveys, 22 breeding pairs of mountain hawk-eagles were confirmed, and there is a possibility that more pairs exist. In addition to these pairs, chicks, young birds, and single adult birds were also confirmed, adding up to 50 mountain hawk-eagles all together in the area.


 


In 2010 and 2011, 2 nesting areas and 6 nesting areas, respectively, saw fledging. The average breeding success rate (the number of nesting sites with chicks confirmed/the number of surveyed sites) for the two years is 23%, not so high, raising a concern for the possible decrease in the population in the future. We were unable to identify any specific reason for breeding failures, but many breeding interference activities by wild bird photographers are being acknowledged, which is expected to be a big problem in the years to come.

Collaborators

Nozomu Mitarai

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