Endangered ferret bouncing back

An endangered black-footed ferret is shown in this undated photo. The ferret’s eyes glow bright green under light in the darkness, helping officials track its numbers. A reintroduction site near Seligman has helped return the species from the brink of extinction.  Arizona Game and Fish Department via Cronkite News Service

An endangered black-footed ferret is shown in this undated photo. The ferret’s eyes glow bright green under light in the darkness, helping officials track its numbers. A reintroduction site near Seligman has helped return the species from the brink of extinction. Arizona Game and Fish Department via Cronkite News Service

A ranch just outside this northern Arizona town is home to more than cattle and horses. In acclimation pens and in burrows dotting the surrounding landscape, black-footed ferrets are devouring prairie dogs and making baby ferrets as they help return the species from the brink of extinction.

It's a big turnaround from two decades ago, when the only ferret species native to North America had vanished from Arizona and most of its range from the Great Plains into the West and parts of Mexico and Canada. Its numbers dwindled to fewer than 20.

In 1996, Diamond A Ranch in Aubrey Valley became one of 11 reintroduction sites in the U.S. and Mexico. With the black-footed ferret now numbering in the hundreds at the various sites, officials say the program has been a success.

"It's huge," said Carrie King, who leads the Arizona Game and Fish Department's reintroduction effort. "It's a classic back-from-the-brink-of-extinction tale."

The facility here conditions black-footed ferrets to survive in the wild and then releases them. The goal is a self-sustaining population.

About 300 black-footed ferrets have been released onto the ranch. Officials can't say exactly how many ferrets are out there, but King said they are finding more ferrets that have been born in the wild.

Still, it's a long road back for the ferrets. While there were at least 665 as of 2006 across the 11 sites, disease poses a threat along with the decline of the ferrets' staple diet: the prairie dog.

A black-footed ferret eats about 110 prairie dogs annually. But prairie dog numbers have dwindled over the decades as much of the prairie was developed into farmland and towns and people eradicated prairie dogs as pests.

Meanwhile, sylvatic plague, a disease spread by rodents, and canine distemper have proven deadly for the ferrets.

Listed as endangered in 1967, the black-footed ferret was thought at one point during the 1970s to have gone extinct. In 1981, about 120 ferrets were discovered in Wyoming.

Between 1985 and 1987, the U.S. Fish and Wildlife Service captured the last 18 ferrets and launched a captive breeding program. It also established reintroduction sites in areas with large numbers of prairie dogs.

"Without reintroduction and monitoring, we'd lose them all over again," said Scott Larson, a biologist with the Fish and Wildlife Service. Federal officials are working with state agencies, including the Arizona Game and Fish Department, as well as American Indian tribes, zoos and conservation organizations.

The groups hope to bring the ferret population to 1,500 by 2010, which would qualify the species for threatened, rather than endangered, status, Larson said.

At Diamond A Ranch, black-footed ferrets are put in acclimation pens, where they are trained to hunt prairie dogs. Ferrets crawl into their burrows, eat the prairie dogs and live there.

"It's not pretty," said Jennifer Cordova, a wildlife technician with Arizona Game and Fish. "But not everything in life needs to be nice to be protected."

Officials here track their progress in the spring and fall through an effort known as spotlighting, in which volunteers work through the night to shine lights toward prairie dog burrows. Those taken over by black-footed ferrets, which are nocturnal, often show a pair of fluorescent green ferret eyes looking back. In the spring, spotlighting helps provide an estimate of how many ferrets survived the winter. In the fall, it helps officials know where to lay traps so they can bring ferrets in for vaccinations.

In 2006, officials trapped 46 ferrets, 45 of which were born in the wild. As of July of this year, they'd captured 38 ferrets, 37 of them born in the wild.