Last night, Prairiewolf and I attended an interesting lecture at Dyck Arboretum on the reintroduction of the black-footed ferrets (an endangered species) into western Kansas. The speaker was Dan Mulhern, of the U.S. Fish and Wildlife Service. He's a wildlife biologist in charge of the re-introduction project here in Kansas.
A few interesting facts that Dan shared with us....
Black-footed ferrets require large colonies of prairie dogs to survive. Prairie dogs are the ferrets' only food. Not only do they eat them, the ferrets live in the colonies along with the prairie dogs (actually living in the prairie dog burrows). A single ferret will eat about 200 "dogs" per year. While this seems like a fair number of prairie dogs to eat, the ferrets do not occur at a dense enough population to control the prairie dog populations. (Of course, ferrets are far from the only animal that preys on prairie dogs! Prairie dogs are "lucky" enough to be food for a great many other predators - many of whose populations are also in trouble, due to the declining numbers of prairie dogs.)
An aside here: Prairie dogs are seen by cattle ranchers as extremely threatening competitors for grass. Thus ranchers have traditionally done everything they can, including massive poisoning campaigns, to get rid of prairie dogs. The poisons used, not surprisingly, kill many other, "non-target" animals too, from eagles and badgers to turkeys, burrowing owls, and black-footed ferrets.
Black-footed ferrets were thought to be extinct for several years in the 1970's. Luckily a small population was discovered in Wyoming. Because of the threat of sylvatic plague killing off this last population, these animals were captured and formed the basis of a captive breeding program.
All known black-footed ferrets alive today are descended from 7 individual animals captured from that Wyoming population.
Ferret re-introduction is far from a "sure thing," especially in Kansas. In this state, local governmental units have the legal right to go on private property and poison prairie dogs, even if the property owner specifically wants the prairie dogs on his or her property and/or doesn't want the poison used. There have been legal battles being fought over the prairie dog colonies that form the home ground for many of the reintroduced black-footed ferrets on a large block of land owned by 3 landowners. The Logan County government is trying to assert its "legal right" to poison these prairie dog colonies, and the land-owners are trying to keep them from being able to do so. For a while, the case was being tried in Shawnee County; recently the venue for the case has been changed to Logan County itself.
In the meantime, almost 50 years to the day since a black-footed ferret was last seen alive in Kansas, 24 ferrets were released in Logan County on December 18, 2007. Thirty-three percent (33%, or 8 animals) were confirmed to survive the first winter and by the fall of 2008, 4 litters of ferrets had been observed with a confirmed observation of 16 individuals. Fifty more ferrets were released last fall. Just 2 weeks ago, the second over-wintering survival survey was done. Dan reported that they located 19 ferrets, for a survival rate of at least 29%. (While these survival rates seem low, they are actually a little high for ferret re-introduction projects.) At least 7 of the ferrets located this month are females, so hopefully more litters will be born this summer.
It's an exciting and hopeful project, an attempt to right a wrong that we humans should never have let happen. Will it be successful? There is no way of knowing. Not only do the ferrets face the normal, biological hurdles of predation, disease, and the vagaries of weather, they also face the immense hurdle of human political pressure against the prairie dogs they depend upon. That's the wildest card of all.