Why do so many birds disappear in the winter? These days, it’s a question the average eight-year-old could probably answer.
For centuries, though, it was one of the great unsolved scientific mysteries. In the mid-1600s, an Oxford-educated academic did suggest that birds migrated — but, less impressively, he thought their destination was the Moon.
Otherwise, the consensus was that the birds hibernated, and that the reason we didn’t see them doing it was because they slept at the bottom of rivers and lakes. As late as 1801, an American scientist sought to prove this once and for all by the simple process of throwing some weighted-down swallows into a nearby river.
Sadly, after he’d pulled them back up, he was forced to report that they were ‘reduced, not to a state of suspended animation, but of absolute death’.
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