November 26, 2012
Beavers On Parachutes
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Image by Jennifer Wade. Beaver photo by stevehdc (Flickr/Wikipedia); background photo by Megan Fogarty.
Just the title — Transplanting Beavers by Airplane and Parachute [PDF] — of this 1950 report in the Journal of Wildlife Management raises questions. Like, for goodness sake, why? And how? Did they specially make tiny beaver-sized parachutes and goggles, and push them out of the cargo hold, one by one, like a tiny dam-making army? Once on the ground, did the beavers suffer post-traumatic stress from the sudden drop? Or did they spend the rest of their days mourning in rivers, longing for another taste of the sky?
Fortunately, the article by Elmo W. Heter from the Idaho Fish and Game Department answered all our questions. Even before the parachuting began, the agency had been in the practice of transplanting beavers whose populations had outgrown their habitats so that they became an annoyance on farms and orchards. But the mountainous, forested and “generally inaccessible wilderness” in Idaho had “complicated the beaver-transplanting program,” the report explains. The game department tried moving them by horse and mule, but it was “arduous, prolonged, expensive, and resulted in high mortality among the beavers.” Not to mention that the pack animals became “spooky and quarrelsome” after dragging the understandably upset beavers for days and days.
Heter doesn’t say exactly how he and his colleagues came up with the brilliant idea of an airdrop, though we’d like to have been in on that meeting. They got war surplus parachutes from the Idaho Forest Service, and placed the animals in boxes, one pair in each box. Settling on the release mechanism required some innovation:
The first box tried had ends made of woven willow. It was thought that, since willows were a beaver’s natural food, the animal would gnaw his way to freedom. This method was discarded when it was discovered that beavers might chew their way out of these boxes too soon, and be loose in the plane, or fall out of a box during the drop.
Finally, they rigged up a tension-banded box that cinched tight from its own weight in the air, but snapped open to let the beavers out once reaching the ground. After concluding that 500 to 800 feet was the ideal beaver-dropping altitude, it was time to go airborne.
Satisfactory experiments with dummy weights having been completed, one old beaver, whom we fondly named “Geronimo,” was dropped again and again on the flying field. Each time he scrambled out of the box, someone was on hand to pick him up. Poor fellow. He finally became resigned, and as soon as we approached him, would crawl back into his box ready to go aloft again. You may be sure that “Geronimo” had a priority reservation on the first ship into the hinterland, and that three young females went with him. Even there he stayed in the box for a long time after his harem was busy inspecting the new surroundings. However, his colony was later reported as very well established.
During the 1948 fall season covered in Heter’s report, only one of 76 beavers failed to survive the flight to his new home, due to lightweight ropes used on the first set of drops that allowed him to wiggle out of the box and climb on top. “Had he stayed where he was, all would have gone well; but for some inexplicable reason, when the box was 75 feet [off] the ground, he jumped or fell from the box,” wrote Heter.
One wonders what the native fauna thought of all these beavers dropping from the sky. At any rate, transplanting via parachute saved money and man hours, and left the animals healthier at the end of their journey. When Heter’s team checked in on them the following season, each of these Felix Baumgartners of the animal kingdom had acclimated successfully to their new homes.
Thanks to Mal McKay and Kelly Rand for the tip.









[...] vol. 14, no. 2, April 1950, pp. 143-7. The Atlantic did a nice piece about it, as did The Daily Planet. The author, at the Idaho Fish and Game Department, McCall, Idaho, [...]
Pingback by Improbable Research » Blog Archive » Transplanting Beavers by Airplane and Parachute — November 26, 2012 @ 8:45 pm
Fascinating article–and made me LOL a couple of times! A good example of innovating technologies and techniques sepcifically for the beneit of of the natural world, rather than using exisiting ones as they are, which can sometimes have undesirable consequences (since they were first and foremost designed for humans).
And quite simple and neat too! If this was NASA or something, they’d have spent immense fortune and manpower developing remotely-controlled eletromechanical boxes (with GPS traceability to boot) that wouldn’t have functionned a lot better than their simpler, cheaper counterparts.
It might be a bit late, but well done Idaho Fish and Game Department!
Comment by S.Mikhail — November 27, 2012 @ 2:58 am
Hmmm…how exactly did they know the mortality rate from the drops? They couldn’t have been there observing them all because of the difficult terrain, the given reason for this bizarre idea. It’s logically likely that more of the poor beaver suffered on those drops than are reported. In what season were they dropped? Was there time to establish lodges and dens before winter? If nothing else, stress would be high. How do they know the surviving, stressed beaver ever found each other again? That one colony was successfully established says nothing about the total number of beaver sacrificed to an experiment.
Comment by JT — November 27, 2012 @ 11:21 am
Hi JT, you’ve got some good questions there. Most of them are answered in the PDF report by Heter linked at the top. They noted the ideal transplanting time was July and August, because any earlier and the beavers would migrate, but any later and they wouldn’t have time to get settled in before winter. However, later he does say they did the parachuting in “the fall of 1948,” without specifying the months, given that they observed them all to be successful, it seems like it must have been soon enough before winter.
There actually would have been about 19 colonies, not just one. Heter explains that the ideal grouping was 4 beavers (1 male and 3 females, or 2 males and 2 females) to start a colony, so with 76 beavers, that would make 19 colonies (with a pair in each box, so two airdrops per colony). Heter says “observations made late in 1949 showed all the airborne transplantings to be successful.” The report doesn’t directly answer how they knew for sure all the beavers survived the drop, but flying at just 500-800 feet, and given that the box opened immediately upon reaching the ground, it seems likely that they could have observed from their vantage point above by circling around.
Comment by Heather Goss — November 27, 2012 @ 12:03 pm
[...] Aquí se hacen eco de un artículo científico de los 50 en el que en Idaho, para abaratar costes en las reintroducciones de castores, éstos se lanzaban desde avioneta, más o menos tal que así. [...]
Pingback by Soltar bichos con paracaidas. Todo un clásico « Quince quinces y un chorlito — November 27, 2012 @ 2:40 pm
[...] the rest of the story at Smithsonian’s Air & Space magazine. Link -via [...]
Pingback by World’s Strangest | The Great Beaver Drop — November 28, 2012 @ 2:35 am
[...] the rest of the story at Smithsonian’s Air Space magazine. Link -via [...]
Pingback by Von what-the-f*ck » Blog Archive » The Great Beaver Drop — November 28, 2012 @ 4:55 am
As God is my witness, I thought beavers could fly!
Comment by Les Nessman — November 28, 2012 @ 9:31 am
[...] day in Idaho some people got together and decided to parachute beavers into the mountains. This is that story government report. Like this:LikeBe the first to like this. This entry was [...]
Pingback by Because, why not? | Not So Fast — November 28, 2012 @ 6:53 pm