Origins of the Myth
From around the 12th century onward, the barnacle goose was enveloped in one of the most curious natural history myths of the Middle Ages. Medieval Europeans were puzzled by the bird’s breeding habits because the goose was never observed nesting or laying eggs in their own lands. Its breeding grounds in the remote Arctic were unknown, and the bird seemed to appear suddenly in Europe during the winter months.
To explain this mystery, a legend arose that barnacle geese did not hatch from eggs but instead grew spontaneously from goose barnacles (marine crustaceans, Lepas anatifera) attached to driftwood. Goose barnacles are filter-feeding crustaceans with a stalk and a shell, somewhat resembling the shape of a goose's head and neck, and were often found on floating timber along the coasts of Britain and Ireland.
People believed that the barnacle goose was born from these barnacles as they fell into the sea and transformed into fully grown geese. This theory was documented by medieval writers such as Gerald of Wales in the 12th century and was accepted by some scholars and even ecclesiastical authorities.
Impact on Religious Dietary Laws
Because of this myth, barnacle geese were sometimes treated differently from other birds in religious dietary rules. For instance, during Lent in some Christian traditions, meat from birds was forbidden, but because barnacle geese were believed to come from the sea, they were sometimes considered "fish" and therefore allowed to be eaten on fasting days.
This loophole was important in medieval times when food restrictions were stringent, and it also illustrates how the barnacle goose myth intersected with cultural and religious practices. shutdown123