'Little vampires': Wildlife agencies release 10 black-footed ferrets in northern Arizona
SELIGMAN — Wildlife officials released 10 endangered black-footed ferrets at Arizona's only active ferret reintroduction site Wednesday, the latest development in a decades-long effort to save the species from extinction and create a sustainable wild population in the state.
Wildlife biologists released the ferrets into abandoned prairie dog burrows in a stretch of juniper-studded prairie called the Aubrey Valley/Double O Ranch reintroduction site, located west of Seligman in northern Arizona. The animals emerged from purple and gray cat carriers, crawled through sections of black corrugated tubing and darted into their new, wild homes under the light of a full moon.
All 10 of the animals are only four months old, born at the U.S. Fish and Wildlife Service's National Black-Footed Ferret Conservation Center in northern Colorado. At the center, FWS officials provided them with live prairie dogs to hunt and kill once every week. The 10 kits will now hunt wild prey for the first time in their lives.
Wildlife agencies have released a total of 257 ferrets at the site between 2005 and 2019. The population seems to have peaked at 123 individuals in 2012, making it potentially the most successful reintroduction site in the country at the time.
Since then, however, ferret numbers have plummeted, bottoming out in the spring of 2024 at two observed individuals. As of Wednesday, officials wondered if the site, and therefore the state of Arizona, had any wild ferrets left.
"We're hoping to rebuild our population," Jennifer Cordova, a wildlife specialist with the Arizona Game and Fish Department, told wildlife workers on Wednesday. "We're really trying to kickstart it."
After releasing each ferret, wildlife workers hammered stakes mounted with game cameras into the tawny earth by each burrow. Over the coming winter, officials will continue to monitor the newcomers using the cameras and in-person animal counts.
One male ferret, released by a team from FWS, proved particularly hesitant to leave its crate. The kit hissed and chittered for about three minutes before workers could coax it into the abandoned prairie dog burrow selected for it.
With a hamster carcass as a welcome snack, the kit retreated into the earthen hole and made itself at home. Following the light of their headlamps, the team paced back to their cars.
"Good luck, buddy," someone said.
Plague outbreaks complicate recovery work
Wednesday's release followed more than 30 years of federal and state government efforts to wrangle the black-footed ferret from the brink. The only ferret species native to North America, the little predators had all but disappeared from the continent's wild ranges by the 1970s, when scientists commonly agreed it was extinct.
The ferrets reappeared in 1981 when a Wyoming farm dog sniffed one out and brought it home to its owners. Since then, breeding and reintroduction programs enabled under the Endangered Species Act have kept the black-footed ferret on life support.
Officials have established reintroduction sites in five states, with two in Arizona. Aubrey Valley/Double O Ranch is the only active site in the state. The Espee Ranch site northeast of Seligman received 99 ferrets between 2007 and 2009, but officials believe the site is now empty.
In the meantime, breeding programs at facilities like the National Black-Footed Ferret Conservation Center and the Phoenix Zoo have continued producing generations of ferrets for reintroduction. The programs periodically exchange animals to maintain genetic diversity.
While Wednesday's ferrets came from the ferret center in Colorado, some were descendants — "grandkits," as one zoo worker jokingly called them — from ferrets bred at the Phoenix Zoo.
Officials believe the villain behind the Aubrey Valley/Double O Ranch ferrets' steep decline since 2012 is the same one that has caused much of the species' demise across the country: plague. The sylvatic plague, first introduced to the United States in the early 1900s, infects ferrets and prairie dogs through fleas, killing the ferrets directly and wiping out their food sources. Neither the prairie dogs nor the ferrets have any natural defense against it. The sylvatic plague is the same bacterium that causes bubonic and pneumonic plague in humans.
For years, wildlife officials and researchers have engaged in a small-scale biological war against the plague, spreading insecticides to kill the fleas and vaccinating prairie dogs and ferrets.
FWS biologist Jessi Miller said in an interview that officials have discovered sylvatic plague at the Aubrey Valley/Double O Ranch site recently."There have been plague-positive results in both prairie dogs and in some of the carnivore samples that they've taken from coyotes," Miller said. "There currently still is plague out there, but we have been treating out there."
To prepare the Aubrey Valley/Double O Ranch site, state officials have spread oral insecticides for prairie dogs, and all 10 new ferrets have been vaccinated. As they continue monitoring the ferrets, wildlife workers say will vaccinate every individual they find.
In addition to the plague, ferrets have struggled generally from prey and habitat loss.
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'Little vampires' try to adapt to habitat
Prairie dogs make up roughly 90% of a black-footed ferret's diet and provide their only source of shelter. With the greatest canine length-to-skull size ratio of any mammal (according to FWS personnel), the black-footed ferret is the modern world's miniature saber-toothed cat.
Some wildlife workers like to call the predators "little vampires" because of their protruding fangs (the ferrets' bite can puncture welding gloves, according to wildlife workers). And like vampires, they hunt at night. While prairie dog colonies are asleep, the ferrets sweep into their burrows and catch them by surprise. When the prairie dogs abandon the burrow, the ferrets will take it over and claim it as a new home.
When seeking out a relocation site for ferrets, wildlife workers look for large, contiguous prairie dog populations. That search for prairie dog habitat is more difficult now than it would have been in the early 20th century. Scientists and government sources commonly cite a more than 90% loss in historic prairie dog habitat due to the arrival of European settlers who poisoned the rodents and tilled the prairies where they lived.
One of the United States' four prairie dog species, the Utah prairie dog, is listed as threatened. All three others are considered "at risk" and have been petitioned for listing as threatened or endangered by FWS.
Considered a "keystone species" for North American prairies, prairie dogs provide burrows and food to a host of animals other than ferrets. Burrowing owls and mountain plovers make homes in their burrows while hawks and coyotes eat them. Beyond supporting the ferrets themselves, wildlife officials say black-footed ferret rehabilitation provides benefits to prairie dogs and all the other species that rely on them.
"I always think of the prairie dog habitat as a habitat type," said Tina Jackson, FWS black-footed ferret recovery coordinator. "Prairie dogs are a wonderful species because they're a lot like beavers. They're a lot like these other animals that can create a whole ecosystem."
At least at the Aubrey Valley/Double O Ranch site, prairie dogs are plentiful enough for the ferrets. The only difficulty there is the region's local prairie dog species, Gunnison's prairie dogs, tend to live in more dispersed colonies than black-tailed and white-tailed prairie dogs.
Individual black-footed ferrets typically require 130 acres of prairie dogs to provide them with sufficient prey, according to Jackson. With Gunnison's prairie dogs, that number increases, adding increased habitat requirements for Arizona's ferrets. Aubrey Valley/Double O Ranch has been the only successful reintroduction site in the country with Gunnison's prairie dogs.
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Why biologists want a diverse ferret population
Wildlife officials hope a recent expansion of the black-footed ferret's possible reintroduction area in Arizona will bolster the species. Last November, FWS drastically increased the zone where ferrets can be reintroduced. Officials are now considering four new sites for ferret reintroduction.
Because the reintroduced ferrets are classified as "experimental populations" under the ESA, officials say landowners cannot be punished for accidentally killing or harming a ferret while working on their properties.
Miller said wildlife officials hope the new reintroduction sites will create more geographically distinct islands of ferrets, providing Arizona with more opportunities for success, and more backups in the case of failure.
Ultimately, Arizona's ferret islands could come to resemble a smaller version of the national system already in place, a rapid rotation of booms and busts at prairie locations across the central-western part of the country. As the Aubrey Valley/Double O Ranch ferrets fell from their zenith after 2012, the ferrets at the Conata Basin in South Dakota were building their numbers. Now, Conata Basin — currently the most successful reintroduction site in the country — may have reached a crossroads as Aubrey Valley/Double O Ranch gets a fresh start.
"They did have a plague outbreak in (Conata Basin) this summer, and we got a lot of partners to show up and help manage that plague outbreak," Jackson said. "They are just finishing up the spotlight efforts for ferrets up there. So we're waiting to hear how the numbers look for the ferrets, hoping that the ferrets are still doing well up there."
In the meantime, Aubrey Valley/Double O Ranch's newest generation is taking its first steps toward an uncertain future, and newborn ferrets are greeting the world every year under human guidance. After dropping off 10 little vampires in Seligman, an Arizona Game and Fish Department plane continued down to Phoenix, where it delivered more ferrets to add genetic diversity at the zoo's breeding program.
Whitney Heuring, a conservation and science manager at the zoo, said she hopes to continue the ferret work for fear of what will happen if the species is lost.
"I think all species play an important role in their ecosystems, and sometimes you don't realize how important that role is until they're gone," Heuring said. "It's important to preserve the diversity of species on the prairie."
Ferrets from the zoo will be part of Arizona's next ferret release, scheduled for the spring of 2025 at the Aubrey Valley/Double O Ranch site.
Austin Corona covers environmental issues for The Arizona Republic and azcentral. Send tips or questions to .
Environmental coverage on azcentral.com and in The Arizona Republic is supported by a grant from the Nina Mason Pulliam Charitable Trust.
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