In 2010, scientists used electric fencing to protect Montana’s black-footed ferrets; coyote sightings in fenced areas fell from 42% to 7%

Fences are seen as something that keeps livestock from wandering away. They are usually constructed for delimiting borders, holding in animals, and securing properties. In Montana’s grasslands, scientists used fencing for the opposite purpose: to keep coyotes out and give endangered black-footed ferrets a safer place to raise their young.

The experiment took place in 2010 at UL Bend National Wildlife Refuge, where scientists were looking for ways to improve black-footed ferret survival. In a report published by the U.S. Department of Agriculture and the U.S. Fish and Wildlife Service, researchers installed 7.7 kilometers of portable electric fencing around portions of two prairie dog colonies to reduce coyote access. During the 68-day research, the number of coyotes, which were observed in the preserved zone, dropped from 42 percent before fencing started to merely 7 percent after it, and several newly born ferrets had the opportunity to grow.

The project addressed a long-running problem for the black-footed ferret population. Once believed to be extinct in the wild, the animals have since been released into several locations in the American West over the past 30 years. Another part of the program involves keeping them alive long enough to procreate, which has been just as important due to the predators that the youngsters run into shortly after emerging from their dens.


Why coyotes pose such a challenge

Black-footed ferrets inhabit prairie dog colonies nearly all their life. They depend on those animals for food and on their digging ability to get underground shelter. Unfortunately, the openness of the prairie makes them more susceptible to large predators.

Coyotes are skilled hunters able to cover long distances in search of food. Although the presence of predators in nature is normal, it creates problems for conservationists trying to bring back endangered species already in decline in numbers. Instead of removing coyotes from the area, the scientists wanted to see whether they could limit predator access.

A fence designed for predators, not ferrets

Unlike traditional ranch fencing, the fencing system was unique. The study describes the use of portable electronet fencing but does not specify solar-powered operation; remove this unsupported claim.

Another ability of the design allowed prairie dogs and black-footed ferrets to go through the fence, while large animals such as coyotes were prevented from entering it. When a coyote touched two alternating fence wires, it received a strong electric shock and usually turned away before crossing into the protected area. The researchers were constantly checking on the fencing system throughout the study so that the damage caused by the wind could be fixed, electrical shorts could be cleared, and batteries repaired.

Measuring whether the strategy worked

Rather than making assumptions, the research team monitored the performance of the coyotes before, during, and after the erection of the barrier. Prior to the erection of the barrier, 42 percent of the total coyote sightings were recorded in the chosen areas for protection. Nevertheless, once the barrier started working, the number decreased to 7 percent. After the barrier was removed at the end of the breeding season, coyote sightings in the monitored areas increased to 47 percent, suggesting that the fencing, not changes in coyote behavior, accounted for the earlier reduction.

There were positive observations with regard to the young ferrets as well. Out of the 6 ferrets that spent most of their time in the protected areas, all survived due to the presence of the barrier, while some of the ferrets living in unprotected areas died. Yet, the researchers admitted that the sample size was too small to draw any conclusion.

Implications for black-footed ferret conservation

The Montana project showed that conservation does not always require permanent infrastructure or large-scale predator removal. A timely temporary measure implemented at the proper spot can have a notable impact. Also, the researchers conducted a cost evaluation related to the installation and upkeep of the barriers and found that this measure was reasonable only when there was a constant positive improvement for kits. This is crucial since black-footed ferrets belong to those few species of mammals that are the most endangered in North America. Therefore, instead of making attempts to remove predators from their habitat, try to protect the animals for a certain period of time.