by Mike Thompson, Wildlife Biologist
Montana Fish, Wildlife & Parks
Seeley Swan Pathfinder
December 24, 1998
by Mike Thompson
A trip to Missoula for Christmas shopping nowadays includes an opportunity to view bighorn sheep between Rainbow Bend and Bonner. And, I think it's fair to say that Bob Henderson deserves the lion's share of credit for giving this annual Christmas gift to people who travel Highway 200.
So, why is Bob firing shotgun blasts at the very sheep he brought to this area only a few short years ago?
Bob is a wildlife biologist with FWP, based in Missoula, and his recent behavior is not necessarily evidence of dementia. His shotgun blasts are non-lethal, and they're experimental attempts to avoid another incident like the one that occurred near Bonner recently.
I'm referring to a sheep-vehicle collision on Highway 200 that resulted in the death of a four-year-old ram. Of course, there's no good or practical way to keep wildlife from crossing busy highways and getting hit on occasion, but this incident was of unusual importance. In the first place, we're talking about relatively uncommon and prized animals when we're talking about bighorn sheep. And, in the case of the Bonner sheep, we're talking about 20 or so animals (upwards of 25% of the local population) that are making a habit of living on and beside the highway.
"The borrow pits along Highway 200 are probably some of the more productive and attractive feeding areas on this sheep range," Bob reported after a recent inspection. The borrow pits provide open water, which in turn, keeps the grass and weeds green and succulent for grazing. They also collect minerals in the sand that's applied to the road surface during winter, as well as any salts that might accumulate.
Productive as this roadside buffet may be, it is not critical to sheep survival in the lower Blackfoot. If anything, it's detrimental, by putting sheep in the paths of vehicles.
So, Bob decided to intervene, with some reservations. FWP doesn't have enough employees and time to shepherd wildlife populations through every risk they face, and generally must allow natural selection to take its course. But, the sheep situation at Bonner seemed an appropriate place to try some aversive conditioning.
You know about aversive conditioning. It's what your dad did to you when you did something wrong. And, you remember your response. You didn't do it again. At least, you worked harder to keep from getting caught.
When Bob reached for the shotgun, he had obviously decided it would be best to be stern at first, and then ease up later if warranted. Instead of lethal cartridges, however, he used a variety of charges designed to make a blunt impact and lots of noise.
He's been visiting his flock a couple times per week, and when he finds them near the road, he reminds them of their mistake with some fireworks. Prior to taking this course of action, sheep were seen routinely along the road. On Bob's first visit with the shotgun, it took a few shots and a variety of charges to establish his dominance. When he returned a day or two later, the sheep had to learn their lessons all over again, although not nearly so many shots were fired.
By the third visit, Bob's flock knew Bob. They were not hanging around the road as much and they were on the move once the pickup door cracked open.
It will be important to observe whether Bob's efforts will actually alter the behavior of these sheep and reduce their risk of mortality. There are so many hours and days when Bob cannot be with them that it would certainly be easy for the sheep to continue using the borrow pits. All they need to learn is to run when they see Bob. But, will they learn to avoid the borrow pits before they learn that they only need to avoid Bob?
That's the experimental part of the operation, and the results will help guide FWP's response when confronted with similar problems in the future, whether at Bonner or elsewhere.
So, don't be surprised if you see FWP herding sheep with a shotgun this Christmas season. It's not something you'd normally see depicted on a greeting card, but still, there's good will all around. Merry Christmas!