Once a thriving predator on prairie landscapes, the black-footed ferret was squeezed out of its range by agriculture and development, and their populations ravaged by diseases like sylvatic plague, which was introduced from Asia at the turn of the 20th century. Ferrets’ main source of food, prairie dogs, have long been considered pests to agriculture on the plains, and thus dramatically reduced in numbers through sanctioned poisoning and killing. As HCN’s Cally Carswell wrote in 2011, “as the prairie dog goes, so goes the black-footed ferret.” By 1979, the ferrets were considered extinct.
But in 1981, a dog in Wyoming brought home a surprising gift, revealing a small population, which scientists began collecting for captive breeding. By 1987, the last wild ferret was captured, bringing the remaining population to 18 individuals. Since then, more than 7,000 kits have been born in six captive breeding centers across North America. Yet efforts to rebuild the wild populations have been stymied by several factors, including diseases like plague and canine distemper, as well as lack of suitable habitat. Earlier this fall, two legislative changes broke down barriers to new habitat possibilities, boosting the ferrets' chance for success.
The first change occurred at the federal level, with the passage of a “safe harbor” agreement that would help drum up support from private landowners who might otherwise fear the liabilities that come with having an endangered species on their property. Many landowners are wary of endangered species protections because if they damage habitat for a protected species, they could face prosecution. Safe harbor agreements allow landowners to participate in reintroduction efforts without worrying about that caveat.
The second win for the black-footed ferret this fall came when the Colorado state legislature decided to allow Colorado Parks and Wildlife to participate in reintroduction. Since 2000, the legislature has had to approve state involvement with federal reintroduction for any species that wasn’t already found within the state’s borders when it was federally listed. Even though the black-footed ferret had been found in Colorado historically, it had vanished from the state by the time it was listed under the Endangered Species Act. This essentially blocked reintroduction on Colorado public lands because the recovery team didn't want to act without the state’s buy-in.
With the newfound support from the state and added protections for private landowners through the safe harbor agreement, biologists on the black-footed ferret recovery team started a new reintroduction site in Colorado in late October. They headed out to the 60,000-acre Walker ranch in Pueblo with 35 microchipped ferrets and set them loose. “I started out 20 years ago to get black-footed ferrets. We finally have a situation where landowners can help with an endangered species without putting restrictions on their land,” rancher Gary Walker told the Pueblo Chieftain. The Walker Ranch became the 21st reintroduction site since efforts began in the early 90s, and the first under the new safe harbor agreement.
Another reason that some ranchers are drawn to black-footed ferret recovery is that they are a natural predator of the prairie dog, which has been known to destroy grasses that ranchers want to keep healthy for cattle. Some ranchers hope that reintroducing the ferret will mitigate their prairie dog problems. Yet in reality, while the ferrets may help to control prairie dog populations, they won’t eradicate the dogs, says Julie Lyke, deputy recovery coordinator for the National Black-Footed Ferret Conservation Center near Ft. Collins, Colo. If they did, “the ferrets would be putting themselves out of business,” she says. In other words, if the ferrets eat too many prairie dogs, their own populations will crash.
Only a few hours from the Pueblo ranch, the staff at the Cheyenne Mountain Zoo, one of the six breeding facilities, is excited to have a release site so close, and the Walkers are excited to be part of the program. Interest from landowners is starting to grow in other parts of the ferret’s 12-state range as well. Since Oct. 31, the Ferret Conservation Center has received half a dozen calls, largely from conservation-minded people who are drawn to the compelling story of the ferret’s recovery, says John Hughes, a field biologist with the center. He says that in choosing a release site, they look for at least 1,500 to 3,000 continuous acres of prairie dog habitat to support a healthy ferret population, and neighboring landowners who will be tolerant of the endangered animals. “We don’t want to enter into reintroduction with too many conflicts,” he says.
Finally, with the guarantee to landowners that they won’t face liabilities while participating in the recovery program, and with the Colorado legislature’s seal of approval, new reintroduction efforts can begin in Colorado and surrounding states where the ferret once thrived.
Katie Mast is an editorial intern at High Country News. Photos courtesy U.S. Fish and Wildlife Service Mountain-Prairie Region.