NEAR MENTOR, Minn. — The little critters are everywhere, it seems. Scurrying across the road, running through the grass and darting down their holes at the sight of humans, only to peek their heads back above ground moments later.
To unfamiliar ears, the chirping sounds they make could be mistaken for birds.
They’re Richardson’s ground squirrels, a species of special concern in Minnesota also known as flickertails for the way they constantly flick their tails; North Dakota, of course, is the Flickertail State.
By any name, they’re cute — and curious.
It’s a cloudy afternoon in late June, and Emily Hutchins and Bruce Lenning of the Minnesota Department of Natural Resources are showcasing the 2,184-acre Mentor Prairie Wildlife Management Area in Polk County, home to Minnesota’s largest colony of Richardson’s ground squirrels, and the management efforts to keep the population thriving.
Richardson’s ground squirrels spend much of the year in underground burrows, but when above ground, they favor short grassland habitat, which gives them a better view of predators.
To provide that habitat at Mentor Prairie, the DNR contracts with two cattle producers to graze portions of the WMA, said Hutchins, DNR area wildlife manager based in Erskine, Minn.
“We manage specifically for them on this wildlife area by implementing season-long grazing,” Hutchins said. “So, the cattle are out in this pasture from mid-May until the end of October, and the purpose of that is to keep the grass short enough to make good habitat for these squirrels.”
That would be nearly impossible without the cattle, she said. The management regimen also includes spraying to control weeds such as thistle and wormwood.
Based on the abundance of Richardson’s ground squirrels, the management strategy is working at Mentor Prairie. The cattle grazing in the distance seem to find the WMA to their liking, as well.
And no, the holes the ground squirrels dig to create their extensive network of burrows aren’t hazardous to her cattle, said Terrill Bradford, who lives north of Fertile, Minn., and grew up on the land that became Mentor Prairie WMA in the mid-’90s.
Bradford grazes 32 cow-calf pairs at Mentor Prairie and also has about a dozen horses on the site.
“We don’t run a lot of horses up here, but cows, not a problem,” she said. “I wouldn’t want to go running across there with my horse, just because there are so many holes, but like grazing out here, (the cattle) are perfectly capable of staying out of trouble.”
Bradford’s father managed the site for cattle operations that owned the land until The Nature Conservancy bought the property at auction in 1994, selling it to the DNR a year later.
The sellers even requested the land be managed to maintain the Richardson’s ground squirrel population, Hutchins said.
“That has been the way we’ve managed it for the last 20 years anyway, and certainly (Richardson’s ground squirrels) were here long before that,” she said.
Richardson’s ground squirrels spend 4 to 8 months a year hibernating. Many of the ground squirrels scurrying across the WMA on this day soon will be underground and out of sight, Hutchins says.
Adult males go first and begin hibernating in early July, she said, followed by adult females at the end of July. Juvenile ground squirrels will stay above ground until November or December, Hutchins said.
The adult males won’t emerge from their holes until March, she said.
Hibernation is a survival strategy to prevent the ground squirrels from outcompeting each other for food, Hutchins said. Richardson’s ground squirrels subsist on a diet of seeds and leaves.
“Otherwise, they’d be eating each other out of house and home,” she said. “You can imagine all year long if there were this many squirrels out and it gets dry in the summer, and there’s less to eat.”
Females, which are only capable of breeding for 2 to 3 hours on a single day of the year — that’s not a misprint — have a 23-day gestation period and will give birth to a litter of five to eight young, which are about a month old when they emerge in late May or early June.
“I would say the young ones have been above ground maybe a month now,” Hutchins said. “When they come up, they’re just like gerbils — they’re so small.”
While Richardson’s ground squirrels are abundant at Mentor Prairie, that’s not the case everywhere in western Minnesota. The state is at the eastern edge of their range, Hutchins says, and the loss of shortgrass habitat is affecting the population of these nongame mammals.
The DNR, along with the Minnesota Biological Survey, is working to step up survey work to get a better handle on Richardson’s ground squirrel numbers in the state, said Lenning, regional nongame wildlife technician for the DNR in Bemidji.
The Minnesota survey involves playing a distress call recording and then counting the Richardson’s ground squirrels that appear within a specified area, Lenning said.
“There hasn’t been a lot of that work done in many years,” he said. “We’re trying to survey all the historical sites and the more recent reports of them, and this year, I know there were 82 sites surveyed, and they were only found at 11, so that’s kind of scary.”
The DNR in recent years has designated the Richardson’s ground squirrel as a species of special concern in Minnesota. As a result, they no longer can be hunted or trapped in Minnesota, Lenning said.
“People used to go shoot them like prairie dogs and now they can’t do that,” Lenning said. “There’s going to be some change in the verbiage of the hunting and trapping synopsis this fall so people can easily understand that.”
Besides Mentor Prairie, private pasturelands in adjacent Red Lake County and nearby Nature Conservancy lands have Richardson’s ground squirrel colonies, Hutchins says. There’s also a colony near the Holiday Stationstores in East Grand Forks, and they’re abundant at Grand Forks Air Force Base, according to a recent “Commander’s Action Line” update.
That makes sense, Hutchins says; Richardson’s ground squirrels seem to do fine in urban settings as long as they’re not persecuted.
“Airports, too — they’ll be in places like that,” she said. “They can live on crop field edges, too, as long as it’s something that’s not really tall.”
At Mentor Prairie, they’re definitely a draw for wildlife watchers who know about them, Hutchins says.
“They’re not common, and people that know about them certainly do come here to see them and do some birdwatching and nature observation,” she said.