Bird wisdom comes slowly sometimes, and sometimes it is delayed by wild tales and total fabrications.
Take the matter of migration, wherein birds leave in one season and return the next.
Aristotle, the renowned philosopher, wrote that swallows often hid in holes in the ground to escape cold weather. The Bishop of Uppsala wrote about fishermen hauling up nets full of swallows hibernating underwater “among the canes and reeds.”
Even Carolus Linnaeus, the founder of modern taxonomy in the 18th century, believed swallows passed the winter beneath lakes. And a prominent ornithologist named Elliott Coues wrote “I see no reason why a Swallow should not stay a while in the mud in a state of suspended animation.”
It took a long time for ornithologists to work out that birds simply migrated to escape cold weather. What’s more, it was discovered this migration often took place by night. But at one time, many scholars thought the missing birds had simply hidden in the mud.
In truth, only one bird comes close to such hibernation. The common poorwill enters a state of dormancy and spends the winter in places such as rock crevices and hollow logs. They are the only bird known to do this.