Wildlife Friendly Fences
 | Author:
Allison Kosto, Broadwater County Extension Agent
MSU Broadwater County Extension Agent |
Wildlife Friendly Fences
Allison Kosto, MSU Broadwater County Extension Agent
Fences… a necessary evil of our Montana agricultural lifestyle. They are used for controlling and protecting livestock, serving as a barrier or marking boundary lines. Yet these same fences can also be a hazard to wildlife by blocking or altering animal movements and limiting access to forage and water. Animals that collide with or become entangled in fences can be seriously injured or even killed. Additionally, damage from wildlife can be costly to landowners. However, fences can be designed or altered to control livestock and facilitate proper movement of wildlife at the same time.
Poorly designed and maintained fences create several issues. Fences that are too high make it difficult for animals to jump. Loose or broken wires make it easier for animals to entangle their legs. Injured animals have a low survival rate and if they can’t pull free, they slowly die. Woven wire creates a barrier for young animals, stressed or injured animals, and even bears and bobcats who go through fences. A study done by Utah State University in an area of Utah and Colorado found that on average, one ungulate (deer, elk, antelope, etc.) per year became tangled for every 2.5 miles of fence. The study also found that most animals died if they are caught in the top two wires, and that young animals were eight times more likely to die in fences.
Carefully consider the placement of fences. Observe wildlife movement, key habitat areas, water access and migration patterns. Design the fences in these areas to allow easy wildlife movement. Save impenetrable fences for devoted areas such as haystacks, gardens, orchards, etc. Work with the land’s topography. Fences are more difficult to traverse when they are on a steep slope or next to a deep ditch. As the slope increases so does the height that the animal must jump. Rail fences are easier for animals to navigate than wire but are more expensive. Wire fencing is more common and can be wildlife friendly with proper wire placement. If the site does not receive a lot of livestock pressure or is seasonal, a three-strand fence is more wildlife friendly than a four or five strand. A buck fence or a jackleg fence should be avoided. Its three-dimensional design makes it difficult for animals to traverse. For residential fences, avoid fences with spikes or pickets which can impale animals trying to jump.
The top wire or rail should be 40 inches or less in height. The distance between the top two wires should be no less than 12 inches apart. Deer and elk can easily tangle their back legs if the wires are too close together. The bottom wire or rail should be at least 16 inches off the ground to allow wildlife to crawl under. Smooth wire also reduces tangling. Increasing visibility of the top wire allows wildlife to navigate it easier. This can be done with high-visibility wire, PVC, flagging tape or other markers. Research on sage-grouse habitat in Wyoming, Idaho and Montana showed that fence markers can reduce fence collisions with birds by 70 to 80 percent. Fence stays are devices that reinforce the fence between posts and maintain wire spacing. When well maintained, fence stays help prevent sagging and can reduce entanglement. However, they can also be easily bent which actually makes the situation worse.
Another technique is the use of drop-down fences or removable crossings. These are great options for seasonal wildlife movement. A herd of elk can cause major damage to a fence especially when pushed during hunting season. Creating a large gate at a major crossing area can reduce the damage and the amount of time and cost to make repairs. Removable electric fence is also a great way to provide a temporary fence.
If you have miles and miles of existing fence, the thought of altering fences to make them more wildlife friendly can be daunting. However, it’s okay to start small. Pick one area a year to work on. I recall one summer during college when my dad sent me around the ranch with a marking stick to move the top and bottom wires on our existing fences around our hayfields. It is a good opportunity for exercise along with helping wildlife! Even without any major alterations, just keeping the fence in good repair is important to reduce wildlife injuries and damage.
For more information, contact MSU Extension in Broadwater County at allison.kosto@montana.edu or 406-266-9242. Montana Fish, Wildlife and Parks and the Natural Resource Conservation Service (NRCS) can also offer technical assistance for wildlife fencing and habitat enhancement projects. Sometimes cost-share programs are also available.
