Note 46 — The Ballad of Svipdag
Henry Adams Bellows translation
Sickle: i.e., tail feather. With this the circle of impossibilities is completed. To get past the dogs, they must be fed with the wing-joints of the cock Vithofnir; the cock can be killed only with the sword in Sinmora’s possession, and Sinmora will give up the sword only in return for the tail feather of the cock.