This yakitori might have been crane meat and eaten by tono-sama (a person with higher rank), since the literature includes a description of 'Tsuruniku no suimono" (clear soup of crane meat).
同文献には「鶴肉の吸い物」の記述もあるので、ツルの肉を焼き鳥にして殿様が食べていたのかもしれない。