"…these Fowls, which make such Changes, and observe their Seasons, to pass and repass between this and the Moon"

So says the 1703 pamphlet Whence Come the Stork, and the Turtle, the Crane, and the Swallow, authored by an unnamed “Person of Learning and Piety” who turned out to be English minister Charles Morton, a man who, despite his most valiant efforts at performing science, went down in history for giving us one of the most stunningly ridiculous theories of where birds went during winter: our moon. 

Morton based that lunarcy on the newly-developed theory of gravity, surmising that migrating birds took to the highest skies so they could escape the pull of Earth, and coast easy on their 200,000+ mile trip to the moon’s lakes. Oh yeah, I forgot to mention that Morton and his contemporaries thought that the moon was covered in vegetation and liquid water, although they never did explain the resulting problem of gray plants and gray water and gray everything.

If you’re thinking to yourself “this sounds bonkers,” that’s because it is bonkers. But until just a few centuries ago, lots of people were certain that birds, despite their obvious ability to fly, definitely couldn’t fly thousands of miles every season. That was just too much. Or if their theories did allow for birds to make long trips to escape the cold, the destinations and purposes were equally batty (flight-related pun unintended).

Let’s take a look at a few of the wackiest theories:

Aristotle’s theory of transmutation: This great Greek thinker, who lived during the 4th century BC, noticed that when the red-breasted Redstart disappeared, the red-breasted Robin showed up. They look similar enough, so naturally one turned into the other, right? Amazingly, the biological theory of transmutation held on in one form or another until Charles Darwin’s time. 

Sleeping with the fishes: How did Aristotle and his contemporaries explain the many birds that disappeared in winter and did NOT get replaced by similar species? He proposed that swallows and other birds buried themselves in the mud, frozen solid until the spring thaw. Aristotle was so influential in his incorrectness that this idea lasted until at least the 16th century, demonstrated by the above woodblock print showing fishermen harvesting swallows from a frozen lake, made in 1555 by Swedish bishop Olaus Magnus. It might be a crazy idea for birds, but thanks to antifreeze-infused blood, some species of frogs can actually pull this off

Homer’s warrior cranes: Aristotle wasn’t the only Greek with goofy ideas. In Homer’s Iliad, he writes of cranes flying to “the world’s end” to battle armies of mythical Pygmy men (rather disparagingly, European explorers gave various tribes of short-statured native people the name “Pygmy” in the 19th century). Over the millennia, the tale of goat-riding Pygmies battling hordes of cranes spread popped up throughout Eurasia, from Aesop’s fables to Pliny the Elder. At least they got the migration part right?

Geese don’t grow on trees… heck, they don’t even sit in ‘em: Since Barnacle geese (Branta leucopsis) were never seen breeding in their European coastal habitats, their origin story was left to the sea. Certain barnacles common in the area had similar coloring and often extended feather-like feeding appendages called cirri.

Since these barnacles grew on driftwood, it was thought that somewhere there existed trees full of budding gooseberries that would drop baby birds into the water each spring. This myth was so common, that some Catholic bishops declared the birds, being made of seafood and not poultry, acceptable for the dinner table during Lent.

Of course, now we know that all of these birds migrate with seasons, accomplishing some of the most amazing feats of navigation and endurance in the animal world. It’s fun to laugh at these ideas of old, but they’re also a reminder that what is rational today may be ridiculous tomorrow. As Richard Feynman once reminded us to ask ourselves, “what witches do we believe in now?”

If you want to learn some amazing (true) science about where birds go during winter, how they navigate, and how they power their epic excursions, check out my latest video: “Where Do Birds Go In Winter?”, or watch it below: