In the new year, Boulder plans continued removal of prairie dogs as the rodents achieve record influx

Few are ambivalent about prairie dogs. Some Boulderites are ardent fans of their removal, no matter the means. Others cheer their necessity to the food system and environment, and oppose their extraction — especially when that extraction is achieved lethally.

This “complicated issue” has “torn the community in half,” Tory Poulton, Boulder’s Open Space and Mountain Park’s prairie dog ecologist, said in an interview. 

Poulton presented at a city meeting on Tuesday, Dec. 13, giving updates on prairie dog activity on city land. This month, Boulder County will hold a similar meeting to address dog happenings on their properties. If echoing city trends, the county will have to deal with an inundation of the rodents. 

Poulton said prairie dogs added more than 5,000 acres of city open space to their domain this past year — the most ever recorded. Recent drought is partly to blame, as it created more sparsely vegetated land that is the dogs’ desired habitat. How to deal with this increase is an ever-evolving challenge. Starting in the latter half of 2021, the city began a lethal control program, along with live relocations, that will continue in 2023. 

“It’s a really tough management situation,” Poulton said. “Some decisions make one portion of the community unhappy, then other decisions make the people who were unhappy happy and those who were happy unhappy.”

Those leasing city agricultural land are often advocates of prairie dog removal. Pastures are one of the swaths affected by the rodents, as cattle grazing combined with prairie dog clipping can lead to desert-like conditions. Yet despite the ease of blaming prairie dogs for Boulder’s expanding wasteland, that’s not the whole story. 

Prairie dogs are, like any animal, doing what they can with the circumstances they’re given. And through monocropping and overgrazing, we’ve offered prairie dogs a golden opportunity to deteriorate the landscape.

“A lot of the negative impacts from prairie dogs stem from human conversion of native systems,” Poulton said.

Poulton explained that when we till (or churn up) the soil and plant non-native grasses for grazing or hay production, “the native soil structure, soil chemistry, microbes and fungus in the soil all get disrupted, and more or less eliminated.” This destruction of natural systems makes the land “lose resiliency to prairie dog digging activity.”

Such resiliency isn’t gone from everywhere in Boulder. In the grasslands to our south, where native grasses send roots into untilled soil, Poulton said prairie dog colonies have persisted without the side effects of bare soil and noxious weeds.

In these resilient systems, prairie dogs are essential to other native animals. Their burrows are used as homes for snakes and burrowing owls; their bodies are food for coyotes, foxes, falcons and others. The endangered Black-Footed Ferret, no longer in Boulder, has a diet of almost entirely prairie dogs. It’s also known as the Prairie Dog Hunter. 

But Poulton said the Black-Footed Ferret “requires a lot of prairie dogs to be successful,” and it’s unlikely the city has enough of the rodents on their land to support ferret reintroduction. Boulder County, however, is toying with the idea, as is Rocky Flats National Wildlife Refuge. To control the rodents’ reach and protect farmland for now, however, the city is strategically moving some rodents, and killing others.

Lethal control: Efficient but not completely effective

City Council approved lethal control of prairie dogs on city land in August of 2020. It wasn’t until the late summer and early fall of 2021 that the approval was implemented.  Using a PERC, or a Pressurized Exhaust Rodent Controller, city-hired contractors pump carbon monoxide into prairie dog burrows. 

In 2022, the city killed prairie dogs on 167 acres with another 94 planned for 2023. Though more efficient than relocation, lethal control isn’t completely effective. Unless sites are actively managed, there’s a risk of recolonization. Since 2018, on land where prairie dogs have been removed — whether through lethal control or relocation — 6% has been repopulated by the rodents.

Poulton said city staff are doing everything they can to cut down on the need for lethal control. This includes building barriers to keep prairie dogs away from where they’re unwanted, as well as restoring native vegetation that can cause the dogs to leave of their own volition.

Even as rodent colonies expanded, this past year the city was able to bring back enough vegetation on some plots that the rodents no longer felt welcome. Prairie dogs prefer sparsely vegetated land. So if you grow more vegetation, they’ll search elsewhere for habitat. Cover crops — including pumpkins, peas and sorghum — were used to accomplish this.

“The goal is to create a plant community and manage that plant community so it’s no longer suitable habitat for prairie dogs.” said Eric Fairlee, OSMP’s agricultural land restoration manager.

Relocation is another tactic of getting rid of prairie dogs without killing them. Working with the Humane Society, the city has trapped and relocated many of the rodents, though not without tribulations. One struggle was rabbits, who find prairie dog traps as inviting as the target critters, adding expense through their extraction and trap resetting. 

When prairie dogs are successfully trapped, however, the city has had relocation success. Previous receiving properties — where relocated prairie dogs are put — now have thriving colonies with many pups in tow. One site is the Mesa Sand and Gravel Colony by the Marshall Reservoir, a receiving site for both 2019 and 2020 relocations. Despite portions of the property burning in the Marshall Fire, the colony is expanding.

The city is also doing their best to protect colonies on land allotted to the rodents. Sylvatic Plague vaccines were scattered across 275 acres of city land this past year. The same illness that brought humans the Black Death in the dark ages still regularly wipes out prairie dog communities. The plague can also affect those who eat the dogs, like the aforementioned Black-Footed Ferret. By vaccinating one species the city is protecting others.

For the foreseeable future, prairie dogs in Boulder will require “constant management and monitoring,” Poulton said. Through irresponsible farming practices, humans crippled the land and set the stage for desertification. The goal now is to try and keep prairie dogs from finishing the job people started.

That doesn’t mean such management will be without detractors. Just as OSMP has a multitude of competing goals — agricultural leasing, biodiversity, and prairie dog maintenance — community members also have differing desires that will maintain friction around the issue.

“It’s hard to tell someone if they’re right or wrong about their strongly held views on prairie dogs,” Poulton said. “Someone who is trying to grow hay or graze cattle has legitimate concerns about prairie dogs reducing the forage for their animals or their ability to grow and harvest hay. And people who value prairie dogs as part of the native ecosystem are absolutely right. And if they feel it’s wrong to kill animals, that’s a reasonably held point of view as well.

“There’s no single solution that is acceptable to the majority of people.”