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 again in spring. The two first opinions have been proved, and it seems have found credit; the last has been treated as ridiculous, and almost an old woman’s tale. Natural history, as all the other histories, depends not always upon the intrinsic degree of probability, but upon facts founded on the testimony of people of noted veracity. —Swallows are seldom seen sinking down into the water, Swallows have not such organs as frogs or lizards, which are torpid during winter, ergo, Swallows live not and cannot live under water. — This way of arguing, I believe, would carry us, in a great many cases, too far. . . . The question must therefore be decided by facts; nor are they wanting here: Dr. Wallerius, the celebrated Swedish Chemist, wrote in 1748 . . . “That he has seen more than once Swallows assembling on a reed, till they were all immersed and went to the bottom. . . . He attests likewise, that he had seen a Swallow caught during winter out of a lake with a net drawn, as is common in Northern countries, under the ice: this bird was brought into a warm room, revived, fluttered about, and soon after died.”
Kalm cited a half dozen more affidavits of swallows netted in winter lakes and revived in warm rooms. Then, he added his own inexplicable experience:
I can reckon myself among the eye-witnesses of this paradoxon of natural history. In the year 1735, being a little boy, I saw several swallows brought in winter by fishermen, from the river Vistula [in Poland], to my father’s house, where two of them were brought into a warm room, revived, and flew about. I saw them several times settling on the warm stove (which the Northern nations have in their rooms) and I recollect well that the same forenoon they died, and I had them, when dead, in my hand.
These are facts, attested by people of the highest quality, by some in public offices, and by others, who tho’ of a low rank, however made these affidavits upon oath. It is impossible to suppose indiscriminately that they were prompted by views of interest to assert as a fact, a thing which had no truth in it. It is therefore highly probable, or rather incontestably true, that swallows retire in the Northern countries during winter, into the water, and stay there in a torpid state, till the return of warmth revives them again in spring. This question therefore I believe ought for the future to be thus stated: The Swallows in Spain, Italy, France, and perhaps some from England, remove to warmer climates; some English ones, and some in Germany and other mild countries, retire into clefts and holes in rocks, and remain there in a torpid state. In the colder northern countries the Swallows immerse in the sea, in lakes, and rivers, and remain in a torpid state, under ice, during winter.
It goes on. Kalm was one of the most respected scientists of his day and the star pupil of Carl Linnaeus, who likely also found this theory credible.
It sounds crazy and superstitious in an age of bird banding, GPS and easy travel. But what’s crazier? That chimney swifts sleep on the wing as they fly a distance of 8,000 miles twice annually between the Amazon and Adirondacks?
“One has only to consider the life force packed tight into that puff of feathers to lay the mind wide open to the mysteries,” Peter Mathhiessen wrote in The Wind Birds.
Once, at the edge of Franklin Falls Pond, I met an old-timer who told me that a wild otter sleeps around his daughter’s neck when she camps on an island a hundred yards offshore. He also told me that the beavers in the pond across the road come to him when he tosses rocks.
Um, I was skeptical. But then again, I didn’t stick around to verify his observations. As most scientific papers conclude, more or less: “Needs more study.” As Kalm himself wrote, “Natural history ought to be studied as a collection of facts; not as a collection of our guesses and opinions.”
If you are interested in busting winter myths, consider “Putting the Myth on Ice,” a program at the Wild Center, in Tupper Lake, at 1 p.m. Thursday, February 21. Naturalist Andrea Schwander will address, “Bears sleep all winter, plants stop growing and all birds fly south, or do they?” The program will feature demonstrations and some of the Wild Center’s live animals.