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Building wildlife friendly fences

Every year, thousands of big game animals and birds die of injuries caused by fences. However, as a new Colorado Division of Wildlife publication explains, it is possible to build effective fences that meet the needs of landowners and that minimize harm to wildlife.

The new publication, “Fencing with Wildlife in Mind,” explains how to build a variety of wildlife-friendly fences. It also includes instructions on how to construct enclosures around areas to exclude wildlife. When properly built, fences can allow wildlife to move through an area, both in their normal daily movements and in seasonal migration patterns.

The information offered by the publication is based on long-term research and observations by wildlife officers and biologists. In addition, private landowners provided suggestions and designs that they employ on their properties.

“Fences are major investments for landowners,” said Pat Tucker, coordinator of the Habitat Partnership Program for the DOW. “This publication isn’t the final word on fencing, but it does show real life examples of fence designs that work for both landowners and wildlife.”??

A research study of 600 miles of fence line conducted by Utah State University examined carcasses of animals found hanging in the fences, dead animals next to fences, and different types of fences. Here are some of the key findings:

• Woven-wire fences topped with a single-strand of barbed wire were most lethal to wildlife.

• One big game animal was found tangled for every 2.5 miles of fence.

• One animal was found dead next to fences every 1.2 miles.

• Most animals died by getting caught in the top two wires while trying to jump.

• 70 percent of all mortalities were on fences higher than 40 inches.??

• Young animals are eight times more likely to die in fences than adult animals.

• 90 percent of the carcasses found near fences were of young animals that had been separated from their mothers.

While not studied as part of the research project, wildlife officers observe that in urban and suburban areas animals often become hung up and die on decorative and wrought-iron fences.

As summer approaches and fence-fixing time begins, landowners are asked to consider carefully what they need for fencing. Such considerations include:?

• What is the real purpose of the fence?

• Is a fence really needed? Property lines can be defined using well-spaced posts, signs or a specific type of tree or shrub instead of a fence.

• Do livestock need to be kept in a pasture or out of an area?

• Is the fence needed year around? Could it be built to be dropped during migratory times?

• Is the fence going to block a path critical to wildlife habitat?

The best fences for wildlife are highly visible to large animals and birds; allow wildlife to jump over or crawl under them; and do not block access to important habitats and travel corridors.

The primary recommendations for wildlife-friendly fencing are:

• The top wire or rail should be smooth and 42 inches or less from the ground.

• At least 12 inches of space should be left between the two top wires.

• The bottom post or wire should be smooth and at least 16 inches off the ground.

• Fence design should be varied, with some lower sections included to allow for easy crossings at some areas.

• A high-visibility wire or flagging should be used to provide visual markers for animals.

“Many landowners provided us with their innovative designs for use in the publication,” said Ken Morgan, private lands coordinator for the DOW. “Their suggestions help to show other landowners that these designs work in the real world. The effort of landowners to help Colorado’s wildlife is very much appreciated.”

“Fencing with Wildlife in Mind” addresses these and numerous other issues. The publication can be found at the DOW website, http://wildlife.state.co.us/landwater/privatelandprogram/hpp? and can be downloaded for use.