Colorado Biologists Use Drones to Track Endangered Ferrets After Release Near Lamar

Colorado Parks and Wildlife is testing new tracking technology at a Prowers County ranch to understand why more than 100 endangered black-footed ferrets released since 2022 have disappeared from the site with no survivors detected in recent surveys.

CPW and Smithsonian Institution biologists fitted 20 black-footed ferrets with VHF radio collars November 17 at a facility in Wellington before transporting them to Southern Plains Land Trust's Heartland Ranch near Lamar for release November 18. The collars enable researchers to use drones and ground telemetry to track ferret movements during their first seven to 14 days after release, the most vulnerable period when predation rates are highest.

This marks the first time CPW has deployed drones with VHF collars to monitor ferrets in the wild, according to the agency. The technology provides far more detailed data than traditional spotlight surveys and stationary monitoring equipment used previously at Colorado reintroduction sites.

"This project aims to enhance our understanding of the relationship between black-footed ferrets and their predators," said Jonathan Reitz, CPW wildlife biologist. "Specifically, we are investigating which species prey on any black-footed ferrets in the two weeks following the ferret release."

Zero Ferrets Detected After 105 Releases

CPW has released 105 black-footed ferrets at Heartland Ranch since 2022 in partnership with the U.S. Fish and Wildlife Service, Smithsonian National Zoo and Conservation Biology Institute, and Southern Plains Land Trust. Extensive spotlight surveys conducted in fall 2025 failed to detect a single surviving ferret.

Wildlife officials confirmed predators including coyotes, badgers, golden eagles and owls are present at the site through camera surveys and field observations. However, researchers have not been able to determine which specific predator species are responsible for ferret losses or develop targeted mitigation strategies without cause-specific mortality data.

The Smithsonian's collaring project represents the first attempt at cause-specific mortality research for black-footed ferrets in Colorado in more than 30 years, according to CPW. Previous monitoring methods rarely captured direct evidence of predation events or allowed forensic analysis of carcasses.

VHF collars are designed to remain attached for just a few days based on ferret body shape, movement patterns and active burrowing behavior. When collars detach or transmit a mortality signal, researchers can rapidly investigate the site using drones that cover large areas more efficiently than ground teams.

Species Recovery Efforts Span Three Decades

Black-footed ferrets were declared extinct in 1979 before a small population was rediscovered near Meeteetse, Wyoming in 1981. All remaining wild ferrets were captured for emergency captive breeding, with first successful reintroductions beginning in Wyoming in 1991.

CPW established the National Black-Footed Ferret Conservation Center near Fort Collins in 2001 as a captive breeding facility supplying ferrets for reintroduction across the West. Colorado has participated in ferret recovery since the early 1990s with releases at Rocky Mountain Arsenal, Wolf Creek, May Ranch and Heartland Ranch.

The Heartland Ranch site began black-footed ferret reintroductions in 2021. Approximately 30 ferrets were released during the inaugural year, followed by 33 ferrets on October 29, 2022, and continued annual efforts through 2025.

Some Colorado sites have shown better ferret survival than Heartland Ranch. May Ranch confirmed wild-born kits in recent years, demonstrating successful reproduction, according to CPW reports. Predation remains a consistent challenge across all reintroduction sites nationwide, with highest mortality occurring during the first two weeks post-release, especially for captive-bred animals unfamiliar with local predator behavior.

Protective Fencing and Non-Lethal Mitigation

Researchers installed a temporary mesh electric fence around release areas at Heartland Ranch during 2025 to exclude terrestrial predators including coyotes and badgers while allowing prairie dogs and small native wildlife to pass through. The fence aims to provide newly released ferrets a critical acclimation window to establish burrow residency before exposure to predators.

CPW researchers are working to identify which predators threaten ferrets and explore non-lethal mitigation options to reduce future losses. Identifying responsible predator species enables targeted protection strategies such as modified fencing designs, aversive conditioning or adjusted release timing based on predator activity patterns.

The research also includes comprehensive monitoring of ferret movements, burrow selection patterns and predator encounters when VHF signals indicate mortality or collar detachment. Smithsonian researchers seek to understand ferret activities during both day and night throughout the vulnerable two-week period.

Plague affecting prairie dog populations and disease transmission represent additional mortality factors for ferrets at other sites, though predation is the primary concern at Heartland Ranch based on recent monitoring data.

Media Availability November 19

CPW invited media November 19 at 1 p.m. to observe field research operations including the mesh electric fence, drone tracking, ground telemetry and ongoing monitoring at the site south of Lamar. Media representatives were required to pre-register with contact information.

Black-footed ferrets are among the rarest mammals in North America. CPW and the U.S. Fish and Wildlife Service have collaborated for decades to conserve the endangered species following its rediscovery in Wyoming more than 40 years ago.

Colorado Parks and Wildlife operates as an enterprise agency funded primarily through license sales, state parks fees and registration revenues. The agency manages 43 state parks and more than 350 wildlife areas covering approximately 900,000 acres, with operations contributing approximately $6 billion annually to Colorado's economy.