PROBLEM TO BE SOLVED: To provide a bird damage preventive tool which can easily pass between a pair of edge lines. SOLUTION: A bird damage prevention tool 10 is rotatably connected to a main shaft member 11 via a straightly extending main shaft member 11 and fixed branch members 12 to 14 that are continuously provided in the axial direction of the main shaft member 11. The branch bar 1a and the skeleton member 1b having one end rotatably connected to the middle part of the branch bar 1a and the other end rotatably connected to the outer peripheral parts of the movable branch members 15 to 17, It is structured in a skeleton. It is structured like an umbrella frame. In the state where the movable branch members 15 to 17 are moved toward the tip end side of the main shaft member 11, the imaginary circumference Cv that connects the tip edges of the plurality of branch rods 1a is expanded, and the movable branch members 15 to 17 are rotated. When the member 11 is moved toward the base end side, the diameter of an imaginary circumference Cv connecting the tip edges of the plurality of branch bars 1a can be reduced. The bird damage prevention tool 10 includes a lock mechanism 1R that can stop the movable branch members 15 to 17 at a predetermined position in the axial direction with respect to the main shaft member 11. [Selection diagram] Figure 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、真直に延びる主軸部材１１、主軸部材１１の軸方向に連設した固定分岐部材１２～１４を介して、主軸部材１１と回動自在に連結した複数の枝棒１ａ、及び、一端部を枝棒１ａの中間部と回動自在に連結し、他端部を可動分岐部材１５～１７の外周部に回動自在に連結した受骨部材１ｂで、傘の骨組み状に構成している。傘の骨組み状に構成している。可動分岐部材１５～１７が主軸部材１１の先端部側に向かって移動した状態では、複数の枝棒１ａの先端縁を結ぶ仮想の円周Ｃｖを拡径し、可動分岐部材１５～１７が主軸部材１１の基端部側に向かって移動した状態では、複数の枝棒１ａの先端縁を結ぶ仮想の円周Ｃｖを縮径できる。鳥害防止具１０は、主軸部材１１に対して、可動分岐部材１５～１７を軸方向に所定の位置で停止できるロック機構１Ｒを備える。【選択図】図１
