Goose or barnacle?
Barnacles geese are rare visitors to southern Europe and do not nest there. So in medieval times people decided that they didn't lay eggs and were born another way. Because goose barnacles have feather-like arms, barnacle geese were believed to hatch from them. There are illustrations of the process in medieval books. The truth is that the geese lay their eggs in the Arctic. But the names of barnacle goose and goose barnacle have stuck.