https://en.wikipedia.org/wiki/Pfeilstorch

You can guess that now in the 21st century, but we're talking about illiterate peasants who never traveled past their nearest market center. It's naive to assume we can even possibly empathize with their epistemological outlook.

For example, just look at the medieval sources about barnacle geese from the 13th century (from the educated class):

> Barliates, as Aristotle says, grow from wood, and are birds which the common people call 'barnesques', having a similar nature. [1] (I chose a short quote to make a point but please read the rest of the source, it's hardly an allegorical text)

They didn't have the concept of falsifiability or anything even remotely resembling the scientific process (or critical thinking, for the most part). The literate were obsessed with the classics and just took Aristotles and Ptolemy's word for everything, until Copernicus and Kepler had their way. Anything resembling scientific knowledge filtered down to the peasants or came from old wives tails entirely.

Even now with almost universal literacy we have a significant fraction (if not majority) of the population believing in ridiculously stupid nonsense like astrology. I don't find it hard to believe that people thought that geese's life cycle included barnacles.

[1] https://www.medievalbestiary.bestiary.ca/beasts/beastsource1...