WHITEFISH - Forget Capistrano's swallows. Pay no attention to those salmon returning home from the ocean. Monarch butterflies? Yeah, right.
When it comes to the mystery of migration, those critters have got nothing on a pair of Montana grizzly bears born and raised north of Whitefish.
Wayne Kasworm, a bear biologist working for the U.S. Fish and Wildlife Service, penned the bears in big metal traps, carted them across whole mountain ranges and dropped them off deep in a far-flung wilderness.
And when they woke up, they walked home.
"They didn't even zigzag around much," Kasworm said. "From the time they got across Highway 2, they seemed to be on a beeline for home."
He has a few theories about why they might do that, but as to the how of it all, "that's a very, very good question. I don't have an answer to that one."
With birds and other great migrators, he said, several theories have emerged. Perhaps they follow the stars with a sophisticated celestial navigation system. Perhaps they follow the sun. Perhaps they follow magnetic fields. Perhaps they follow a chemical trail, or a visual trail, or an evolutionary trail.
"There are some good questions about how all that works," he said, "but I don't think science has all the answers yet."
It's particularly puzzling in the case of Whitefish's wandering grizzlies, because they weren't following some ancestral path encoded deep in their genes. They were backtracking a route they'd only ever traveled once, and they didn't even follow that road directly.
Instead, they ran cross-country straight for home.
Maybe they could smell it. Maybe they could simply sense it.
"Maybe," Kasworm said, "it's just part of the great mystery.
"I can't say why they did it, and I certainly can't say how they did it. But obviously, they did it."
***
Kasworm met the elder bear - a 10-year-old female - last September, when he caught her in the wilds north of Whitefish Mountain Resort. She was minding her own business, getting ready for winter, when he nabbed her to help augment the grizzly population over in the Cabinet Mountains.
Since the early 1990s, he's moved almost a dozen bears into the Cabinets, hoping to bolster an isolated and precarious bear population there. Until now, he said, the newcomers have stuck around.
The 10-year-old settled in at first, denning the winter in the west Cabinets not far from where he dropped her off. This spring, she moved into the main Cabinet Range, and at one point was ranging about five miles southwest of Libby.
But then she dropped, quite literally, off his radar. Kasworm flew over the region several times, hoping to pick up a signal from her GPS collar, but she was gone.
Kasworm wondered, and worried a bit, but continued his business of bear relocation. About a month ago, in late July, he moved another bear from the area north of Big Mountain, this time relocating a 4-year-old female into the southern Cabinets. She dropped off his map almost immediately, and his searching quickly took him farther and farther afield, eastward, toward her home range.
On Aug. 5, he picked up her signal, not far from where he'd first captured her. She'd traveled 60 miles in six days, and was home almost before she'd left.
"While I was there," Kasworm said, "I thought, ‘Well, maybe I'd better give a listen for that other missing bear.' "
He spun the frequency dial on his receiver and immediately picked up the 10-year-old, back home in the Whitefish Divide. The GPS readings showed she'd hit the trail in May, covering 73 miles in seven days.
"Certainly, these movements out of the Cabinet Mountains were not the intent of the augmentation program," Kasworm said, "but they do provide some interesting insights into the ability of bears to return to their capture location in a surprisingly direct manner."
***
Some have suggested the bears returned home seeking familiar habitat - known berry patches, favorite beetle trees, that sort of thing - but he thinks that doesn't explain the immediate flight of the 4-year-old.
"I don't think this bear even took the time to test the new habitat," he said. She just decided she wanted to go back, and that was that."
Kasworm has no intention of trying to return either of the grizzlies to the Cabinets, but he is planning to capture at least one more bear for the augmentation program before summer's out. This time, though, he'll look farther afield, eastward to the Continental Divide country "to put more real estate between the capture point and the release site."
Whether that will prove enough, however, remains - like so much else in this migration - a tantalizing unknown.
After all, he said, those swallows do seem to find their way back to Capistrano from a terribly long ways away.
