eagle-stone

…The connection with keen eyesight is also seen in the practice of the inhabitants of the Tyrol in Austria of pinning eagle feathers to their hats. In the nests of these birds, a walnut-sized stone or piece of iron ore called an “eagle-stone” is said to be found, which was thought to help the parent bird lay its eggs and was therefore highly valued as a talisman against miscarriage and for marital harmony. Pliny also says that the cause of death of the mighty eagle is hunger, and that as it grows older, its beaks become curved until it is no longer possible to open its mouth. …

*Some of the terminology explanations that mention "eagle-stone" are listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

…鋭い視力との結びつきは，オーストリアのチロル地方の住民が帽子にワシの羽根を差す習わしにもうかがえる。その巣には〈イーグル･ストーンeagle‐stone〉というクルミ大の石ないし鉄鉱石が見つかるとされ，これは親鳥が卵を産む助けに使うものと考えられたために，流産よけや夫婦和合の護符として珍重された。プリニウスはまた，強靱なワシが死ぬ原因は飢えにあるとし，年を取るにつれ両くちばしが曲がってきて最後には口を開けられなくなるからだと述べている。…

※「eagle-stone」について言及している用語解説の一部を掲載しています。

出典｜株式会社平凡社世界大百科事典 第２版について | 情報