Young girl from Oya - Oya no Wakaseko

...Swans were also considered to be the spirits of grain, and there are legends in various places, such as the "Legend of the Falling Grains," in which a swan is the main character, and the "Tale of the Mochi Turned into a Swan," in which a rice cake turns into a swan and flies away. Many tales about swans are found in the Tohoku region, and in the Kakunodate region of Akita Prefecture, a flock of swans that sing during the equinox was called "Oya no Wakaseko." [Kiyomitsu Sasaki]
[Legend]
The graceful figure of the swan has been featured in many poems and music since ancient times.

*Some of the terminology that refers to "Oya no Wakaseko" is listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

…白鳥は穀霊神ともみなされたらしく，白鳥を主人公とする〈穂落し伝説〉や，餅が白鳥に化して飛び去ったという〈餅化白鳥譚〉は各地に見られる。白鳥に関する伝承は東北地方に多く分布し，秋田県角館地方では彼岸に鳴き渡る白鳥の群れを〈大宅の若勢子〉と称した。【佐々木 清光】
［伝説］
　優美な白鳥の姿は古来詩や音楽に多くとり上げられている。…

※「大宅の若勢子」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