Wild Again. David S. Jachowski
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than 58 percent were from Mellette County, where Bob Henderson and the growing ferret research team focused their attention.
The following summer, Dick Adrian quit the ferret project and was replaced by Con Hillman, an ambitious North Dakota farm boy with a bachelor’s degree in wildlife management from Utah State University. Con was keen to make the study of ferrets in South Dakota part of his master’s degree research, and in July 1966 he found a female with a litter of five on a ranch owned by Jim Carr. Over the next sixteen months he would find sixteen more, following a total of three litters around in the night and making careful notes of their behaviors: where they moved, what they ate, and patiently waiting by their burrows to see how long they stayed underground. He reported his research as a master’s thesis defended at South Dakota State University in 1968, and that same year summarized his findings for the public in the short, pioneering paper hidden on the 433rd page of the Transactions from the 33rd Annual North American Wildlife Congress unassumingly titled “Field Observation of Black-Footed Ferrets in South Dakota.”
As I moved forward through the attic file boxes into 1968, 1969, and 1970, reports from South Dakota became more frequently typed and official sounding. A series of scientific publications and symposium proceedings were produced by Con Hillman, Bob Henderson, and a variety of other biologists who collaborated in Mellette County ferret research. I pulled out details from scientific papers showing that scat analyses proved that ferrets almost exclusively fed on prairie dogs. Monitoring reports showed that ferrets rarely left prairie dogs colonies and that they required sizeable prairie dog colonies of at least twenty-five acres in size, and more likely close to a hundred acres in size. All told, during the eleven years of studying ferrets in Mellette County, ninety ferrets were located, and at least thirty-eight young were produced. Yet rather than acting as a single, large, healthy population, the ninety confirmed ferrets were highly dispersed across Mellette and the surrounding eight counties—evidence that this wasn’t the last stronghold but rather just the last fragments of a species on the decline.
Although the meat of the scientific reports on ferrets in Mellette County was focused on methodology and reporting results, the final concluding paragraphs began to consistently end with increased calls for ferret and prairie dog conservation. Poisoning continued throughout much of South Dakota as federal agencies contradicted each other and state and local farm bureaus continued to lobby for prairie dog control. State governors, congressmen, and even biologists continued to believe that prairie dogs were pests to be eradicated. Concessions were sometimes made to at least look for ferrets prior to poisoning—to “clear” the area and confirm that ferrets did not exist where poisoning was to occur. Unfortunately, the surveys were often done during the day and by untrained personnel with prairie dog vendettas. Even if done correctly by those who had actually seen a ferret in the wild, it would have been difficult to find a reclusive ferret during a quick prairie dog “clearance” survey. Thus by claiming to not see a ferret, biologists were able to justify their poisoning of prairie dogs on thousands of acres of ferret habitat on private and public lands. By 1968, a frustrated Robert Henderson left South Dakota. Dr. Springer was reassigned to North Dakota.
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While Con and others were undertaking that first detailed study of ferrets, in October 1966, the Endangered Species Preservation Act was passed by Congress, extending full protection to thirty-six birds, six reptiles and amphibians, twenty-two fish, and fourteen mammals, including the black-footed ferret. That year, funds were appropriated for Dr. Ray Erickson, Assistant Director of Endangered Wildlife Research for the Bureau of Sport Fisheries and Wildlife, to start a captive population of black-footed ferrets at Patuxent Wildlife Research Center on the far side of the country. More than two decades before my father started work there, Patuxent was world renowned because of its history of innovative, successful captive breeding programs for critically endangered whooping cranes, bald eagles, and California condors.
Ray Erickson didn’t get his first batch of wild black-footed ferrets until 1971, when six ferrets were captured from Mellette County and taken to Patuxent. Between 1968 and 1971, Patuxent staff had been practicing by raising European polecats, a stubby-bodied Eurasian ferret species that is the black-footed ferret’s closest living relative. Over three years, they had remarkable success, producing more than 150 offspring and testing breeding and weaning procedures, canine distemper vaccines, and designs for nest boxes and holding pens.
Of the six ferrets transported from South Dakota, four died from a modified live-virus canine distemper vaccine before even arriving at Patuxent. It was a vaccine that worked well on European polecats to prevent a disease now known to be 100 percent fatal to black-footed ferrets. But black-footed ferrets were sensitive to the live-virus treatment, and only males FM-71–1 and FM-71–2 survived.
On September 15, 1972, Con Hillman captured female ferret FF-72–1, injected her with a killed canine distemper virus vaccine this time, and drove her to a secure National Guard compound in Rapid City, South Dakota, for a three-week quarantine. After surviving her period of isolation, on October 4, the female ferret was transported by Con to Dulles Airport in Washington, D.C., where she underwent an additional month of quarantine at Patuxent Wildlife Research Center prior to being placed in a cage adjoining FM-71–1 and FM-71–2 on November 6.
The records I found in the Patuxent attic on ferret husbandry for the three individuals were exhaustive and repetitive. They were being fed a daily diet of 50 grams of dry mink feed, 100 grams of dried dog food, and 20 cc of corn oil—a far cry from killing a prey item that outweighs you by a quarter of your body weight. Prairie dogs bite with sharp incisors, mob you with family members if you venture out during the day, and bury you underground when you are sensed in one of their burrows. Wild lions hunting wildebeest on the Kalahari have nothing on the black-footed ferret hunting prairie dogs on the Great Plains.
But now this relationship was being lost, prairie dog without predator, predator without prey. The ferret population in Mellette County was in a mysterious and precipitous decline. Between 1973 and 1974, three more Mellette County ferrets were trapped and brought to Patuxent. After 1974, no ferrets were seen in Mellette County or in any of the adjacent counties where they had been observed in the past. Ferret searches intensified as the newly established Black-footed Ferret Recovery Team developed a recovery plan in the event that captive breeding might take off or another population might be uncovered. Hundreds of reports came in of ferrets spotted in Kansas, Montana, Wyoming, Colorado, Utah, New Mexico, Nebraska, Canada, and South Dakota. Most of these reports were of little use, unable to be confirmed or far away from prairie dog colonies where ferrets were likely confused with long-tailed weasels. Other reports were more credible, like one dated August 6, 1974, from eminent big cat expert Dr. Maurice Hornocker, who reported seeing a ferret running across Interstate 80 twenty miles west of Laramie, Wyoming, at 9:30 in the morning. All of the reports were scribbled on or stapled to a piece of paper on which it was written that they were unable to be verified or not worth following up before they were filed away only for official records. At the same time, black-footed ferrets were officially considered extirpated in Canada, as well as Texas and Oklahoma, with other states to follow soon afterward.
At Patuxent, captive breeding had stalled. The black-footed ferrets were not breeding successfully like their European polecat surrogates with which the biologists had been practicing for years. Husbandry and feeding regimes were altered and tested with almost no success. In 1976 and 1977, one of the two surviving females produced a litter each year, but all ten kits were either stillborn or died within days of birth.
At the bottom of the last box of files, the final report was dated 1979. By then all captive female ferrets had died, and only a single male remained. He perished later that year, and I thought that there could be few things as delicate as a black-footed ferret. The last individual of an entire species was housed in a building just down the road in suburban Maryland, minutes from the Baltimore–Washington Parkway, and less than an hour from the White House. The leading experts in the world on captive breeding and species conservation had failed. I looked for other file boxes with ferret records. I believed there must be more boxes, more letters, more reports. Something to continue the story, let me believe there were still hidden corners of the western U.S. where the species might persist.
I went down to my father’s office. He was on the phone so I waited