PROBLEM TO BE SOLVED: To provide a nest building prevention tool capable of improving attaching property and attaining a sufficient nest building prevention effect even when the size of a coming bird is different.SOLUTION: A nest building prevention tool comprises: a rod-shaped trunk body 5 extending in a vertical direction Z a branch body 8 having a plurality of branch-shaped portions 7 radially extending from a base portion 6 removably mounted on the trunk body 5, and inclining the more downward as it leaves the more from the base portion 6 and support means 9 mounted on one arm 3a for supporting the trunk body 5. The support means 9 supports the branch body 8 such that a vertical axis m0 passing through a centroid G of a rectangular form B and an axis m5 of the base portion 6 align with each other on the assumption of the rectangular form B in which center axes m1 and m2 of insulators 4a1 and 4a2 and center axes m3 and m4 of insulators 4b1 and 4b2 have apexes at intersection points n1 to n4. The branch-shaped portions 7 are formed such that the projection points of their leading ends on a horizontal plane F are near the individual sides of the rectangular form B and located on an inner side C in a horizontal direction X than the projection region of the individual insulators 4a1 and 4a2 and 4b1 and 4b2 on the horizontal plane F.COPYRIGHT: (C)2014,JPO&INPIT【課題】 取付け性を向上し、飛来する鳥類の大きさが異なる場合であっても、充分な営巣防止効果を得ることができる営巣防止具を提供する。【解決手段】 鉛直方向Zに延びる棒状の幹体5と、幹体5に着脱可能に装着される基部6から放射状に延びかつ基部6から離反するにつれて下方に傾斜する複数の枝状部7を有する枝体8と、一方のアーム3aに設けられ、幹体5を支持する支持手段9とを含み、支持手段9は、碍子4a1,4a2の中心軸線m1,m2と、碍子4b1,4b2の中心軸線m3,m4とが、交点n1~n4を頂点とする長方形Bを想定したとき、該長方形Bの図心Gを通る鉛直軸線m0と、基部6の軸線m5とが一致するように、枝体8を支持し、枝状部7は、その先端の水平面Fへの投影点が長方形Bの各辺の近傍で、かつ各碍子4a1,4a2;4b1,4b2の水平面Fへの投影領域よりも水平方向Xに関して内側Cに位置するように形成される。【選択図】 図1
