Muscovy duck
The production of foie gras occurs on the argument that migrating wildfowl seasonally eat such that their liver naturally enlarges. However, the bird used predominantly in foie gras production is a hybrid of a male Muscovy duck and a female Pekin duck. It has been noted that the Muscovy duck is non-migratory, and both the Pekin and the mulard hybrid cannot fly. Domestic ducks (including the Pekin) are derived from the mallard duck, which is sometimes migratory and sometimes not. Therefore, although the domestic goose might well be adapted to store food before migration, it is less likely that the Mulard hybrid duck has the same potential.