PROBLEM TO BE SOLVED: To provide a bird damage prevention device which can easily pass between a set of edge lines. SOLUTION: A bird damage preventive tool 10 includes a preventive tool main body 1 and an arm metal attachment tool 2. The preventive tool main body 1 includes a spindle member 11 and a plurality of flexible branch rods 12. The plurality of branch rods 12 are arranged in multiple stages in the axial direction of the spindle member 11, and project radially from the outer periphery of the spindle member 11 with the tip end side inclined downward. The arm metal attachment 2 can hold the arm metal A by introducing the arm metal A from the tip side of the pair of holding pieces 2t / 2u. The arm fitting 2 has a regulation hole 2h opened on the tip end side of the pair of holding pieces 2t and 2u. While the plurality of branch bars 12 pass through the regulation hole 2h, the diameter of the virtual circumference Cv connecting the tip edges of the plurality of branch bars 12 can be reduced, and after the plurality of branch bars 12 pass through the regulation hole 2h, a plurality of branch bars 12 The diameter of the virtual circumferential Cv connecting the tip edges of the branch rods 12 can be expanded. [Selection diagram] Fig. 1【課題】一組の縁線の間を容易に通過できる鳥害防止具を提供する。【解決手段】鳥害防止具１０は、防止具本体１と腕金取り付け具２を備える。防止具本体１は、主軸部材１１と複数の屈曲自在な枝棒１２を備える。複数の枝棒１２は、主軸部材１１の軸方向に多段に配置され、主軸部材１１の外周から先端部側が下り傾斜した状態で放射状に突出している。腕金取り付け具２は、一対の挟持片２ｔ・２ｕの先端部側から腕金Ａを内部に導入して保持できる。腕金取り付け具２は、規制穴２ｈを一対の挟持片２ｔ・２ｕの先端部側に開口している。複数の枝棒１２が規制穴２ｈを通過中は、複数の枝棒１２の先端縁を結ぶ仮想の円周Ｃｖを縮径でき、複数の枝棒１２が規制穴２ｈを通過後は、複数の枝棒１２の先端縁を結ぶ仮想の円周Ｃｖを拡径できる。【選択図】図１
