January 12, 2026

To Ensure a Future for Endangered Black-footed Ferrets, Biologists Turn to Tracking Tech

Photo of a black-footed ferret wearing a tracking collar, peeking out of its burrow.

Ryan Jones, Colorado Parks and Wildlife

One mid-November evening in southeastern Colorado, Smithsonian research ecologist Jesse Boulerice walked across the Heartland Ranch Nature Preserve holding a small animal carrier. He stopped at the entrance of a prairie dog burrow and, upon opening the door, his charge leapt out: a black-footed ferret, wearing a specially made tracking collar.

It was one of 26 black-footed ferrets, born and raised in human care, to be reintroduced at the Heartland site through a partnership between the Smithsonian, the U.S. Fish and Wildlife Service (USFWS), Colorado Parks and Wildlife (CPW) and the Southern Plains Land Trust (SPLT), which owns the 43,000-acre property. Since 2022, biologists have released 105 ferrets bred in human care at the Heartland site, but the animals aren’t thriving. In fact, despite yearly spotlighting surveys each fall since reintroduction began, scientists hadn’t seen many ferrets. This year, they hadn't seen a single one yet.

Difficulty in locating reintroduced ferrets could be partially explained by the species’ nocturnal and fossorial (burrowing) natures —they spend most of their lives in prairie dog burrows— and they could be dispersing across the large property. But Kieran Andreoni, the conservation director of SPLT, had a second theory: predators. The Heartland Preserve is home to a wide variety of native grassland species, including large numbers of badgers, coyotes and swift foxes, all of which are believed to prey on black-footed ferrets.

“There’s a steep and very dangerous learning curve when it comes to predators,” said Andreoni. “The fact that we aren't seeing many ferrets after reintroduction is worrying to us. Are predators the issue here, or are the ferrets just taking off?”

If the team wanted the wild population to survive, they had to find out where the ferrets were going and what was happening to them post-release.

Photo of two male biologists attaching a tracking collar on an anesthetized ferret in a veterinary office setting.

The black-footed ferret is one of America’s rarest animals and one of its best conservation comeback kids. The species was believed to be completely extinct in the wild. That changed in 1981, when a ranch dog named Shep brought his owners a dead ferret. While most dog owners would prefer not to receive such presents, this ferret marked the turning point in the species' history. Authorities were notified and found the last remaining population of ferrets at Meeteetse, Wyoming, thanks to Shep. Between 1985 and 1986, USFWS caught the remaining 18 ferrets to establish a breeding center in Wyoming. In 1988, the National Zoo was the first to receive offspring from the founding generation and thus began the Smithsonian’s highly productive black-footed ferret breeding program.

In the decades since, more than 10,000 black-footed ferrets bred under human care have been returned to the wild, bringing an important player back to the prairie ecosystems in the western Great Plains, including Arizona, Montana, Wyoming, South Dakota, Montana, Colorado, Utah, Kansas and New Mexico. The reintroduction program has moved the black-footed ferret from being classified as “extinct in the wild” to “endangered”; an enormous win for conservationists. But the black-footed ferret isn’t out of the woods yet. Wild colonies still face an uphill battle, threatened by the introduced sylvatic plague, significant declines in their prey base, predators and overall habitat loss as humans convert grasslands to farms, roads and developments.

Tracking America's BFF

Boulerice and the Smithsonian’s Great Plains Science team have studied the lives of black-tailed prairie dogs and black-footed ferrets in Montana since 2023. When tracking most animals, scientists can attach a small tag or collar, which can transmit information to satellites or handheld receivers that show the animal’s location. But this technology doesn’t work underground where soil disrupts transmission. To add to the challenge, the ferret’s slender, snake-like bodies make it easy for collars to slip off, while prairie dogs are prone to chewing off the tracking devices during social grooming sessions.

Working with Swansea University, Boulerice and project partners identified specialized tracking devices that could record complex, three-dimensional movements, in a manner known as dead-reckoning. For the first time, researchers could map out in fine detail the movements of animals in the deep, multi-chambered prairie dog burrows. Boulerice believes the data will help scientists learn more about the social structures and habitat use of both species, which could in turn improve conservation strategies to protect ferrets and other grassland species. And although the physical challenges of tracking prairie dogs and ferrets are still present, multiple trials in managed settings and in the field have proven effective.

Illustration of prairie with an underground view of prairie dog burrows. The burrows show a variety of animals using the space.

SLPT and CPW observed high numbers of swift foxes, badgers and coyotes at Heartland, forming the basis of an intriguing research collaboration to identify potential predators of the black-footed ferrets.

“SPLT and CPW were already tracking the movements of swift fox and badgers at the ranch. With the potential to track newly reintroduced ferrets using our new tracking technologies, it gave us a unique opportunity to study the movement ecology and spatial relations between the three grassland species all at the same time,” Boulerice said. “By being in Colorado instead of Montana, we can learn how different environmental factors that vary across the region impact the movement ecology, behavior and survival of these animals, which will be critical to their conservation and recovery.”

This opportunity also gave Boulerice the chance to try out another new tracking method. Traditionally, biologists would spend hours driving across the landscape at night, sweeping spotlights in the hopes of seeing a ferret above ground. But Boulerice could instead use a drone with radio telemetry capabilities and thermal-infrared cameras to quickly detect above-ground collared animals at a distance. This combination of cutting-edge methods, he hoped, would open new doors to understanding this rare species. Once the collared ferrets were released, he fired up his drone and took to the skies to see if the system would work.

Photo of a man operating a drone in an open grassland.

It didn’t take long for the team to start receiving tracking data. The drone, combined with the specialist tracking devices, allowed Boulerice to quickly and safely survey large areas and collect important information. The initial data seemed to support one possible concern about the fate of ferrets at SLPT. Just hours after being released, the collared ferrets began to encounter wild predators.

“The predator is doing what they naturally do, but the problem is that the black-footed ferrets are not acclimated to that,” said Jonathan Reitz, a wildlife biologist with CPW. “They’ve never had any exposure to these animals, and it’s a rough situation for them to be facing so many predators.”

Although the results might seem disheartening at first, they provide crucial insight into the reality reintroduced species face. One possible solution would be ensuring anti-predator behaviors are strongly ingrained in ferrets before they are released, whether as natural instincts or learned via pre-conditioning programs. Alternatively, additional efforts to ensure newly reintroduced ferrets are released in the wild in places with fewer predators may help these animals get a better start in their new environments.

“Conservation of endangered species is all about problem-solving. There is always a reason why species are imperiled. If it was an easy fix, they wouldn’t be endangered in the first place,” Boulerice said. “Our efforts with black-footed ferret conservation are a perfect representation of this. It’s often two steps forward, one step back.”

Despite the challenges, Boulerice is optimistic for the recovery of the species and grassland ecosystems more broadly. And this release was a full circle moment for Boulerice, as several of the ferrets reintroduced in Colorado were born from the Smithsonian’s breeding program in Front Royal, Virginia.

“When it comes to black-footed ferrets, we have a unique opportunity to be involved in the full picture of recovery, from start to finish, from birth to survival in the wild. Our Smithsonian team’s expertise in animal management and reproductive biology combines with our Great Plains Science program’s expertise in advanced field research to synergistically improve the conservation and recovery of this endangered species. It is incredibly rewarding to see this all-encompassing approach to conservation come together.”