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One of only three species of ferrets in the world, the North American black-footed ferret has faced a tenuous existence in recent years. The endangered animal requires prairie dog colonies to provide food and shelter. Rural development has fragmented and reduced prairie dog habitat, which in turn has caused severe population declines of black-footed ferrets.
Following its listing as an endangered species in 1973, U.S. Fish and Wildlife Service (USFWS) biologists have conducted intensive searches to locate populations of the nocturnal, subterranean black-footed ferret. Years of searching were unsuccessful until 1981, when a small population was accidentally discovered by a rancher near Meeteetse, Wyo. This discovery gave biologists and researchers hope the species could be saved from extinction.
Little had been known about the elusive and rare black-footed ferret, and biologists began gathering data on its behavior, reproduction and survival rates. But one year after documenting an estimated 129 ferrets, the Meeteetse population experienced a rapid decline.
Canine distemper, a disease for which black-footed ferrets have no immunity, was diagnosed as the culprit. To salvage this last known population, all remaining ferrets in the Meeteetse population were captured and moved in 1987 to captive breeding facilities at the Wyoming Game and Fish Department's Sybille Research Facility.
Initial efforts to breed and rear kits from the captive population were met with frustration. However, by 1988 the extraordinary effort by captive breeding specialists was successful and enough animals were available to expand the captive population to other breeding facilities.
In addition to the Sybille facility, five zoos in the United States and one in Canada are currently housing and breeding about 240 black-footed ferrets. Offspring from captive breeding have enabled biologists to reintroduce 49 ferrets into the wild. A milestone toward recovery of the species occurred in 1992, when the reintroduced ferrets produced six wild-born kits.
Black-footed ferret reintroductions in Wyoming have continued each following year. In 1994, additional animals were released at sites in the Conada Badlands in South Dakota and in U.L. Bend National Wildlife Refuge in Montana. Ongoing reintroductions are directed toward the national recovery objective of establishing a population of 1,500 free-ranging breeding adults in at least 10 populations. By the year 2010, the goal is to have at least 30 breeding adults in every population.
Research of factors related to survival and mortality are being investigated, along with the development of different rearing and release techniques. While progress has been made, a self-sustaining population of black-footed ferrets in Wyoming hasn't been established. And it's yet to be determined if ferrets released in Montana and South Dakota in 1994 have reproduced, though approximately 25 percent of the animals are believed to be alive.
Biologists aren't optimistic about the black-footed ferret recovery in the wild. As in the past, the loss of the ferret's habitat base -- the prairie dog -- continues to impact their survival.
Sylvatic plague, a deadly disease to prairie dogs, is rampant and decimating many colonies. Recently, a black-footed ferret in Wyoming died after contracting the disease, which wasn't thought to affect the animals. Subsequent plague testing with black-footed/Siberian ferret hybrids resulted in 100 percent mortality. These findings severely limit options for reintroduction. Of the potential sites for reintroduction, only South Dakota is believed to be plague-free.
Other impacts on the ferret's habitat base include chemical control of prairie dogs by agricultural interests. Many states within the historic range of the ferret consider prairie dogs as pests and require their eradication. Few land management plans provide for protection or enhancement of this resource for black-footed ferrets.
Biologists are unsure if the approximately 120 ferrets available for annual reintroductions are enough to establish self-sustaining wild populations. Meanwhile, funding for captive breeding and reintroduction programs are being reduced. The Sybille Facility will remain open through 1996 and at least some of the reintroduction program can continue.
Despite years of progress, decisions regarding the long-term funding are needed to assure the ferret's recovery program. Without funding, the creature's fate could be all but sealed. More than ever, black-footed ferret recovery is truly at the crossroads.
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