Fatty foods save rare squirrels
When cattleman Frank Anderson settled into a remote house in rural Idaho, ground squirrels were the furthest thing from his mind. But once the critters emerged from hibernation, he could hardly ignore them as they devoured the chow he left outside for his dogs.
“The bloody things were eating more dog food than the dogs,” said Anderson, who figured he’d try to get along with the creatures. “They’re cute little rascals; I really get a kick out of watching them.”
The Idaho ground squirrel population on his OX Ranch began to flourish, even as populations elsewhere disappeared. Soon scientists studying the rare squirrels took notice.
“Paul Sherman came out and measured my squirrels, and it turned out they were 20 percent heavier than squirrels anywhere else,” said Anderson. Sherman and Tom Gavin, ecologists at Cornell University in Ithaca, N.Y., say the rancher’s sanctuary pointed to the reason that other squirrel populations were disappearing: The squirrels were no longer getting enough to eat.
Anderson hadn’t realized it, but he’d been feeding what is perhaps North America’s rarest squirrel species. The Idaho ground squirrel is limited to Adams and Washington counties in west-central Idaho. If agencies don’t change the way the land is managed, the squirrels, and the meadows they inhabit, may become a thing of the past.
Idaho ground squirrels don’t look unusual. They stand 6 to 8 inches tall, have short tails and a reddish tinge on their legs and undertails. But the animals lead extraordinary lives, spending less than five months a year above ground.
“They’re like tulips, they come up in the spring, bloom, and then they’re gone for the year,” said Sherman.
When the squirrels emerge from hibernation in early April, a feeding frenzy ensues. They have only a few months to stock up for their next seven-month hibernation. During the spring feast, each squirrel’s body weight more than doubles, and its body fat balloons by a factor of five, said Sherman.
The squirrels don’t have time to bother with low-nutrient food sources they need energy-packed food and lots of it. Most of their fuel comes from fatty seeds produced by native grasses, but they also eat broad-leafed plants and grass.
During the past 15 years, fewer and fewer squirrels have survived from one year to the next, according to Sherman and Eric Yensen, an ecologist at Albertson College in Caldwell, Idaho. Both have studied the squirrels for the last two decades, and both have seen their study populations shrink each year.
One site, with 150 squirrels in 1988, now has only 10 left, and other site populations have disappeared completely, Yensen says.
According to a U.S. Fish and Wildlife report, the total northern Idaho ground squirrel population in 1985 was about 5,000. By 1996, that number had dropped to less than 1,000. Sherman estimates that fewer than 500 squirrels remain today.
Genetic studies done by Yensen and Sherman also show the squirrel populations have become so isolated they are no longer intermixing. That spells doom, Sherman said, because populations hard hit by predators or natural disaster can’t be repopulated by migrant squirrels.
The U.S. Fish and Wildlife Service has taken notice of the squirrels’ plight, and in March 1998 proposed giving the northern Idaho ground squirrel threatened status. A final ruling on the proposal should be made sometime this year.
In the meantime, Sherman and Yensen are spearheading a unique multi-agency effort to boost the squirrel populations. While Anderson’s inadvertent experiment highlighted the role of food supply in the squirrels’ demise, Sherman said, food scarcity is really a symptom of a larger problem.
The real culprit, Sherman said, is a dearth of forest fires. Over the last 50 years, human efforts to suppress forest fires have been so successful that they’ve altered the landscape. In the absence of fire, the montane meadows the squirrels call home have filled in with trees, isolating squirrel populations from one another. Fires favor native plants that have evolved with fire, but with fire gone, the balance has shifted in favor of more aggressive species.
“What we’ve come to realize is that fires are a part of this ecosystem and plants are adapted to it,” Sherman said. “That’s what keeps the meadows open.”
Now, Sherman and Yensen have teamed with Bruce Haak of the Idaho Department of Fish and Game, as well as the U.S. Fish and Wildlife Service, the U.S. Forest Service and the OX Ranch to restore the squirrels’ montane meadows. The ambitious plan cuts down young pine trees that encroach on the meadows, sets a patchwork of small, controlled fires in the meadows, and transports squirrels from large populations into areas that have been restored.
The program is in its third year, and, so far, has been carried out in three areas with about 900 acres, said Rich Howard, a wildlife biologist with the U.S. Fish and Wildlife Service in Boise. Though Sherman cautions that it’s too soon to know for sure, one population has nearly doubled since its habitat was burned over two years ago.
The program is being completed with community support.
“What we have here is a common attempt to do the right thing. We’re collaborating and cooperating rather than dealing with lawsuits and conflict,” said Sherman. One reason the plan hasn’t met with resistance is the steps necessary for restoring the squirrels’ habitat are compatible with current land use, said Yensen. And people realize that keeping meadows healthy is in everyone’s best interest.
“In the long run, (fire) is economically beneficial for everyone,” Yensen said. In the end, it’s not just the ground squirrels. “It’s all the other species that live there, too: elk, beaver, and bluebirds, just to name a few.” (Christie Aschwanden is a writer with High Country News in Paonia, Colo.)
For this week’s Hometown Hero, the Craig Press is pleased to honor Steve Walls.