小規模疎開地の造成がイヌワシの探餌行動頻度に与える効果

• Main Authors: 由井 正敏, 工藤 琢磨, 藤岡 浩, 柳谷 新一
• Format: Article in Journal/Newspaper
• Language: Japanese
• Published: 2001
• Subjects: イヌワシ; 疎開地造成; 探餌行動; 林業; ノウサギ; golden eagle; open land; hunting; forestry; hare; Aquila chrysaetos
• Online Access: https://iwate-pu.repo.nii.ac.jp/?action=repository_uri&item_id=1102; http://id.nii.ac.jp/1318/00001086/; https://iwate-pu.repo.nii.ac.jp/?action=repository_action_common_download&item_id=1102&item_no=1&attribute_id=21&file_no=1

わが国のイヌワシの繁殖成功率は近年低下しており、その原因としてうっぺいした森林の増加が推測される。イヌワシは疎開地や森林内のギャップで狩りを行うため、うっぺいした森林は不適である。このため、秋田県田沢湖町のイヌワシ営巣地を囲む二次林地帯に1-2haの小規模疎開地6ヵ所を伐採造成し、非営巣期のイヌワシの採餌行動の変化を調査した。その結果、造成疎開地における採餌行動頻度は対照区に比べ有意に増加し、その有効性が確かめられた。 Breeding success rates for golden eagles(Aquila chrysaetos) have recently decreased apparently due to the increase in closed canopy forests. As this species hunts in open lands or gaps in the forest, closed canopy forests would be unsuitable. A new supply of open areas around the nest of a pair of these eagles at Tazawako was provided from 1991 to 1997, and changes in their hunting behavior were observed from 1991 to 1998. In the secondary forest zone, six study plots (1-2ha) were established within 1-2 Km from the breeding nest. All of the areas are open habitat types, including clear cutting, selective heavy cutting, and belt cutting. Hunting frequencies increased significantly in these study areas during the non-breeding season. Supply of open habitats of about 1 to 2 ha is effective in increasing the hunting activity of the golden eagle.