Wildlife fences - friend or foe to big game?
In a perfect world, wildlife could exist in a habitat without fences, roaming along unfettered paths through an open landscape. Fences act as a barrier to wildlife movement and seasonal migration. Many animals even collide with fences or get trapped in wires. To help prevent these problems, wildlife managers are taking steps to implement wildlife-compatible fencing designs.
Fences are needed for a variety of purposes — to delineate property boundaries, to contain livestock, to prevent trespass, or to distinguish recreation zones. While no one will argue that fences are needed, it is important to recognize that fences are both barriers and traps for wildlife.
Deer, elk, moose, bighorn sheep and pronghorn are all able to bound over fences, but smooth or barbed-wire can snag and tangle their limbs. This is especially true if the wires are loose or spaced too closely together. Deer and elk jump with their hind legs forward. When the top strands of the fence are too high, too close together, or are loose, they will often ensnare the animal. If the animal cannot untangle itself, it will die a slow and very painful death. Even when wildlife are able to clear fences, or make their way underneath the strands, the barbed-wire often rips and tears at their skin.
Some fences, like woven wire, are solid barriers for fawns and calves. Adults may be able to bound over these types of fences, leaving their young behind. Stranded and unable to follow the rest of the herd, the young will often succumb to starvation or predation.
When woven wire is topped with one or more strands of barbed-wire, the fence becomes a solid barrier for those animals who are either incapable or unwilling to jump or those who are simply too large to slip through the strands.
Fences also pose a serious challenge for birds. Birds can collide with fences, breaking wings or becoming ensnared in the strands. Low-flying birds like ducks, geese, sage grouse, and owls are particularly vulnerable. There have also been a number of reports of hawks who collide with fences when approaching in on prey.
Some consider jackleg or buck and rail fences to be wildlife-compatible, but they are usually built too high, too wide, and the rails are generally placed too closely together for wildlife to pass through. The three-dimensional jackleg design is particularly difficult for animals to leap through. When the jackleg is coupled with woven or barbed-wire, it is especially lethal to wildlife.
Given these serious challenges, the Billings Gazette reported that wildlife managers are on a mission to remove as many fences as they can in order to improve safety for wildlife on public lands.
“A lot of our wildlife areas are made up of homesteads that were purchased by the state,” says Kari Dingman, assistant wildlife area manager at Washington Department of Fish and Wildlife. “A lot of fences and wire remains from where the pastures were fenced off. We come across wire we didn’t know about when we’re doing projects.
“I’ve removed several miles of fence myself, and there’s a lot more out there.”
This past spring, a crew of 11 volunteers organized by the Inland Northwest Wildlife Council devoted a weekend to taking down barbed wire in the Wooten Wildlife Area.
“They’ve been coming almost every year since 2008 and they’ve been a big, big help,” Dingman said.
The group removed several miles of barbed wire fencing in the Tucannon Valley.
While removing extraneous fencing is imperative, wildlife managers are also keen on building fences to protect habitat from livestock and off-road vehicles.
Fortunately, years of research had produced certain protocols for better barriers and the wildlife managers are able to find more wildlife-friendly fencing designs.
“We try to make wildlife compatible fences,” said Jason Lowe, wildlife biologists for the U.S. Bureau of Land Management’s Spokane District. “In this region, most of the consideration is for deer and sage grouse.”
The BLM has adopted fencing protocol that includes specifications on the distance between the wires.
“For example, we have ranges for how high the bottom wire should be off the ground because a lot of times mule deer prefer to go under fences,” Lowe said.
The middle two strands should be closer together in order to leave more room below the top wire. If a deer jumps over the fence, and its leg hits the top wire, there will be enough space so that the wire does not become tangled with the next wire and the deer’s foot will not become trapped.
“Tight fences are safer than loose wires that tangle more easily,” he continued.
Though barbed-wire fences can snag wildlife and rip an animal’s skin, this type of wire is much more effective in keeping cattle out.
“It’s preferable that the top and bottom wires be smooth for wildlife going under or over the fence, while we used barbed wire in the middle to deter the cattle,” Lowe said.
By combining smooth wire and barbed-wire, the fence controls livestock but still allows for passage of pronghorn, deer and elk.
“But for fences that get a lot of pressure, like a fence along a riparian (streamside) area, we’ll use barbed wire on top and smooth on the bottom only. Cattle will challenge a fence to get to green grass. If it’s just a fence through a pasture that’s the same on both sides, they don’t bother it as much.”
When creating jackleg fences, managers recommend making them safe by creating a few well-spaced gaps. Sections of fence can be built with lay-down rails that are positioned in the places where wildlife are most likely to cross.
Managers also recommend creating openings, crossings and passings in fences to allow wildlife to pass when livestock are absent. These features help keep fawns and calves from being stranded, allow passage for animals who are unwilling or unable to jump fences, and help wildlife cross when weather conditions prevent passage over or under fences.
In some regions of Washington, wildlife managers are placing -inch plastic strips on the wires to make the fence more visible to both ungulates and birds.
“Research in Utah led by the Natural Resources Conservation Service quantified the number of sage grouse killed on fences,” Lowe said. “They’re significant sources of mortality especially on the top of ridgelines and within a kilometer from where they congregate on their leks (mating grounds).”
In other areas, managers are installing high fences to steer big game away from conflicts with humans and agriculture.
A large fence near Interstate 90 near Ellensburg has helped reroute some elk from crops during winter on the Oak Creek Wildlife Area, where the Washington Department of Fish and Wildlife has established an artificial winter feeding program to prevent the large numbers of game from starving.
Four years ago, managers installed a deer-proof fence near Wenatchee that has helped decrease the number of wildlife-vehicle collisions on Highway 97A.
The 8-foot-high fence in southeastern Washington that borders the Umatilla National Forest and state-managed wildlife areas in the Blue Mountains Wildlife Area Complex is another example of a barrier that protects wildlife from potential danger.
“It starts on the Wooten Wildlife area at the Tucannon River and runs 26 miles to Asotin Creek to keep elk on public land and out of the agricultural fields,” said Dingman.
While there are many more guidelines when it comes to making various types of fencing wildlife-friendly, it ultimately comes down to three main points: the fence should be highly visible to both ungulates and birds; the fence should allow wildlife to leap over or crawl under; the fence should allow wildlife access to important habitats and travel corridors.