The Birds Beneath the Ice by Mary Thill Where do birds go in
winter? The question has intrigued scientists since BC, dating
back at least as far as Aristotle. In the Victorian era, it was
commonly believed that northern swallows, martins and swifts
hibernate in the sea or under the ice of lakes and rivers. Peter
Kalm, the Scandinavian botanist who traveled the eastern edge of
the Adirondacks in the 18th century, wrote that he observed
swallows in New Jersey on April 10: “I saw great numbers of them
sitting on posts and planks, and they were as wet as if they had
been just come out of the sea.” In a lengthy footnote, he
defended his theory: It has been a subject of contest among
naturalists, to determine the winter-retreat of Swallows. Some
think they go to warmer climates when they disappear in the
Northern Countries: others say, they creep into hollow trees,
and holes in clefts of rocks, and lie there all the winter in a
torpid state; and others affirm, that they take their retreat
into water, and revive aga