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New rule could help black-footed ferrets make a comeback

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Black-footed ferrets are one of only three species of ferrets found in the world and the only one native to North America.

No one said trapping black-footed ferrets at night in the remote Wyoming plains was easy. Even biologists admit spotlighting the nocturnal 3-pound critters hiding among sagebrush and tall, cured grass is probably not the most effective method.

But for right now, it’s the only way to survey one of a handful of colonies of an animal once thought extinct.

“We’re looking for eye shine of ferrets,” said Nichole Bjornlie, Wyoming Game and Fish Department’s nongame biologist, as she bumped along a dark, rutted road in late August. “They have a very, very bright blue turquoise.”

The tiny, ferocious and elusive black-footed ferret is a symbol of a time when endless swaths of prairie flowed uninterrupted across the West, when fat, dirt-colored prairie dogs ruled the landscape and countless animals relied on them for food and shelter.

Black-footed ferrets’ reintroduction has been slow and mired with disease outbreaks and political roadblocks. While locations such as Shirley Basin have provided some of the best hope for their future, even there the populations can fluctuate dramatically. Without new colony locations, researchers don’t believe the species will ever be fully recovered and removed from the endangered species list.

As a result, the U.S. Fish and Wildlife Service plans to announce within the next month a new plan for reintroduction in Wyoming. While the name sounds technical and nuanced – a statewide 10J -- the ruling is a first for ferrets in the country, and some wildlife managers say it may be one of the biggest steps in a path to bringing one of the most endangered mammals in North America back permanently to the West.

“Our ultimate goal is to get the ferret delisted so we don’t have to worry about them so much. If we could get control of (bubonic) plague, I think it’s a realistic goal in my career,” said Zack Walker, Game and Fish’s nongame bird and mammal program supervisor. “It’s something that we can get done. People like ferrets; they’re not a hindrance to a lot of things. It’s just a matter of getting them out to enough places and getting their populations stable.”


Black-footed ferrets have a history of disappearing. They once roamed most of the western prairies of North America, ranging from Canada to Mexico, Oklahoma to Utah.

But through aggressive prairie dog management using poisons, habitat loss from plowing prairie and introduced diseases such as the plague, researchers thought the species was extinct by the 1950s.

In 1964, a small population was found in South Dakota. Only nine remained when researchers took them into captivity, but even those ended up dying by 1979. Black-footed ferrets once again joined the list of creatures such as the passenger pigeon, blinked out by western expansion.

But in 1981, a Meeteetse rancher’s dog named Shep brought a strange-looking ferret to his owner. The ranchers took it to a taxidermist, who realized it was a black-footed ferret. Biologists discovered an entire colony of about 120 animals, Walker said.

Then the population crashed. In five years, only 18 remained. Researchers with Game and Fish scooped up the remaining ferrets and took them to a research station in Sybille Canyon near Wheatland.

Zoos and wildlife centers from Phoenix to Louisville to Toronto accepted black-footed ferrets into their breeding programs, protecting the limited genetic diversity found in the original population. From there, researchers looked to the public for places to reintroduce them. Each of those locations required one basic but ultimately complicated feature: prairie dogs.

Black-footed ferrets “hitched their wagons to prairie dogs,” millennia ago, said Pete Gober, black-footed ferret recovery coordinator for the U.S. Fish and Wildlife Service.

“It was a good bet because prairie dogs are so resilient, but that was before poison, plague and plowing,” he said. “And the greatest of these is plague.”

Ferrets use prairie dog tunnels as their dens and the prairie dogs themselves as food. As a result, any colony of reintroduced black-footed ferrets needs at least 1,500 acres of black-tailed prairie dog colony or 3,000 acres of white-tailed to survive.

“A female ferret defends 100 acres of black-tailed prairie dog colony,” Gober said. “They’re evolved to deal with droughts we can’t even imagine. She is defending in her mind to live when there are only a few prairie dogs left.”

Researchers found the perfect location in Shirley Basin, where prairie dog colonies dot a patchwork of ranches and public land as far as the eye can see. Recovery coordinators gave the area a special designation under the Endangered Species Act called a 10J, which allows ferrets to be incidentally killed during legal land management activities such as haying or plowing.

It was 1991 and the first reintroduction of the species. Biologists were cautiously optimistic for the ferrets, Walker said, and many believed they had a chance at recovery.

But more than two decades later, the creatures remain isolated in Wyoming, their numbers fluctuating.


Like bats and owls, black-footed ferrets are a nighttime animal. Their prey sleeps at night, which is how the carnivores can live off of animals roughly their size, said Game and Fish’s nongame biologist Jesse Boulerice.

Boulerice spent about eight weeks this summer working with crews of up to 10 looking for ferrets in Shirley Basin. Game and Fish teams have done similar surveys since the early ‘90s, monitoring population numbers and animal health.

But like everything with ferrets, catching them is tricky.

Biologists wander designated sections of prairie dog colonies using a spotlight to look for a green color reflected off of the critters’ eyes. After enough hours of staring into the dark abyss, antelope eyes, reflective poles and even moths start to look like the real thing, said Bjornlie, the nongame biologist.

The team caught about five ferrets on average each week this summer. On one chilly night in late August, a seasonal technician trapped a female ferret, bringing it to Boulerice in a 10-foot white trailer converted into a mobile research station equipped with sleeping gas, plague vaccines and bug spray to keep potentially diseased fleas off of the human handlers.

“Start time is 1:32 a.m.,” Boulerice said, putting a mask of anesthesia over the tiny ferret’s face.

Boulerice removed four fleas, carriers of the deadly plague bacteria, and one tick. When he scanned over her back, he found a transceiver and realized she had been caught more than a week before in another prairie dog colony.

The researchers already had her age and body length and had given her vaccines for plague and distemper, so they placed her in a tiny dog crate to wake up from her anesthesia. Within the hour she would be back in the hole where the technician caught her.

About 40 black-footed ferrets were documented in Shirley Basin in 2013. Numbers for 2015 have not yet been calculated. Their numbers declined from about 90 in 2010. Those numbers, however, come with a caveat because of the difficulty of surveying.

“We will assess how we’re doing this year, and then if we need to do something we might take steps toward that, but at least now we are still waiting to get the results back from this year,” Walker said. “If our population is lower, we might take steps into contacting the ferret recovery center to see if we could get more and talk to landowners.”

While the Shirley Basin population is considered a success story, Walker said, it will not be enough to consider black-footed ferrets recovered in Wyoming. The ferrets need more space to live. And in a state like Wyoming, made of patchwork private and public land, they need landowner support.


Shirley Basin rancher Todd Heward rarely sees black-footed ferrets. Their reintroduction really affects him only when people want to tour the critters’ colonies.

Heward welcomed the endangered animals onto his Heward 7E ranch, where his family has lived since 1909, almost 25 years ago. Several other ranchers did the same, all under the unique 10J listing.

“Really it was the non-threat to us as a landowner and our operation, and that was the same for all landowners involved,” Heward said. “Landowners were comfortable enough that if something were to change, their livelihoods would not be threatened.”

Without an experimental, nonessential designation protecting landowners from accidental ferret deaths, ranchers could face strict regulation from the feds, Heward said.

“The 10J has proven to be, to this point, an adequate mechanism for that assurance,” he said. “It has allowed landowners to go along with their business as they need to. It’s allowed for wind development to happen, other energy development to happen without the threat of that species jeopardizing the process.”

Since no black-footed ferrets exist in the wild without being reintroduced, the federal government can assign the 10J designation to certain areas, said Gober.

But until now, it has never applied to an entire state for this species.

Gober and Walker, the Game and Fish nongame supervisor, expect the Fish and Wildlife Service to announce within a month a proposal to make all of Wyoming a 10J. That means anywhere enough prairie dogs exist, and landowners are willing, ferrets could be reintroduced with the benefit of added land protections.

Another option, called Safe Harbor, says any ferrets reintroduced into an area with none to begin with, can be removed at any time at the landowner’s request. The 10J and Safe Harbor can be used together or in place of the other.

Those agreements, together with money from groups such as the Natural Resource Conservation Service, could result in more black-footed ferrets on the landscape, Gober said. It could even mean eventual removal from the endangered species list, which translates to about 3,000 black-footed ferrets across 12 states.

“I think it’s a realistic goal in my career,” Walker said. “People like ferrets. They’re not a hindrance to a lot of things.”

Black-footed ferrets would still likely live in only about one-tenth of 1 percent of their native range – the land equivalent of about half a typical Western county. Their prairie-dog companions have been eliminated from many places, and some ranchers still struggle grazing cattle in areas where prairie dogs consume most of the grass. But that small percent is enough, Gober said.

The predators are already in eight states, Mexico and Canada, one state shy of their recovery goal in terms of distribution. A few more reintroductions each year, and they could potentially be removed from the list in a decade.

It won’t come without work, Gober cautions. Money must still be spent on reintroductions, payments to ranchers for allowing prairie dogs to roam and annual surveys to monitor the population.

Researchers also need to better control plague. Oral vaccines for prairie dogs are in the works and wildlife managers dust for fleas, but the disease is far from handled, he said.

The eventual hope is that one day biologists won’t need to roam the darkened high plains each year with spotlights because the 3-pound animals with turquoise eye shine will be recovered.

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