Wildlife Friendly Fencing

Wildlife friendly fencing is an important factor in maintaining habitat connectivity for wildlife, especially on low volume roads where the goal may be to allow movement of wildlife at grade (rather than funneling wildlife to an overpass or underpass) .   In some cases, where wildlife crossings exist, or there is heavy traffic on a particular road, fencing can act as a barrier and reduce collisions with wildlife, improving driver safety and reducing wildlife mortality.

For this reason, it is important to consider when and how to use wildlife friendly fencing. Many of Montana’s roads are low volume, rural roads where maintaining wildlife movement and connectivity is an overall benefit. In these cases, Montanans for Safe Wildlife Passage (MSWP) advocates for wildlife friendly fencing to allow for the continued movement of wildlife while also achieving goals for livestock safety.

Traditional Right of Way Fencing (5-wire, 6-wire, woven wire, etc.) can act as a barrier to wildlife movement and is often lethal to wildlife, particularly ungulates and young animals (see research below).  MSWP is working with MDT to update policies and educate Right of Way agents to employ wildlife friendly fencing on low volume roads or whenever appropriate.

Wildlife Friendly Fencing Resources

MDT Wildlife Friendly Fencing Design Brochure

A Landowners Guide to Wildlife Friendly Fencing – MT Fish, Wildlife and Parks (Second Edition, Revised and Updated: 2012)

Movement and Distribution Patterns of Pronghorn In Relation to Roads and Fences in Southwestern WY

A Landowners Guide to Fences and Wildlife: WY

Characteristics of Ungulate Behavior and Mortality Associated with Wire Fences

MDT Policies

MDT Memo: Wildlife Friendly Fence Details (December 30, 2010)

Right of Way Manual (Pages 59-60)


Recently, researchers at Utah State University completed a study of wildlife mortality along more than 600 miles of fences in the rangelands of northeastern Utah and northwestern Colorado (Harrington 2005, Harrington and Conover 2006). By repeatedly driving and walking fencelines over two seasons, they tallied the number of mule deer, pronghorn and elk carcasses they found caught in fences and lying next to fences. They also studied which fence types caused the most problems. Here are their key findings:

Snared and Entangled

  • On average, one ungulate per year was found tangled for every 2.5 miles of fence.
  • Most animals (69% of juveniles and 77% of adults) died by getting caught in the top two wires while trying to jump a fence.
  • Juveniles are eight times more likely to die in fences than adults.
  • Mortalities peaked during August, when fawns are weaned.
  • Woven-wire fence topped with a single strand of barbed-wire was the most lethal fence type, as it more easily snared and tangled legs between the barbed-wire and rigid woven-wire.
  • 70% of all mortalities were on fences higher than 40”.

Blocked and Stranded

  • Where ungulates were found dead next to, but not in fences, on average one ungulate per year died for every 1.2 miles of fence.
  • 90% of these carcasses found near fences were fawns lying in a curled position – probably separated from their mothers when they could not cross.
  • Most of these indirect mortalities were found next to woven-wire fences.

Harrington, J.L. 2005. Characteristics of ungulate behavior and mortality associated with wire fences. Master’s thesis, Utah State University, Logan, UT. 48 pp.

Harrington, J.L., and M.R. Conover. 2006. Characteristics of ungulate behavior and mortality associated with wire fences. Wildlife Society Bull.34(5)1295-1305.