PRAIRIE DOG VISUAL BARRIER SETUP GUIDELINES

Visual barriers help control the movement of prairie dogs by providing a visual blockage that the prairie dog is hesitant to approach. Although they are not a complete solution to the problem of confining prairie dogs to specific areas, they are an important component of an effective integrated prairie dog management program. In concert with other techniques, visual barriers can provide a humane and passive means of controlling the prairie dogs movement. In order to be effective, the following guidelines should be kept in mind:

1. Prairie dogs seem to respond to holes where light can pass through the visual barrier. Therefore, when installing artificial barriers no light passage can be allowed along the bottom edge, the seams, or as a result of damage to the barrier. Proper installation and subsequent maintenance should prevent this.
2. Visual barriers are not effective when the barrier separates family groups or “coteries.” When connected burrows can be found on both sides of the barrier, the prairie dogs will continue to use the underground tunnel system and move through the aboveground barrier.
3. The installation of visual barriers is not formal or standard. The methods will change as we gain experience. Current techniques range from the installation of vertical vinyl barriers, 36 inches high, attached to existing fences or erected separately, to the use of vegetation, topography, and horizontal barriers.

Installation of vertical barriers (see diagram) City of Fort Collins, Natural Areas Program:

1. Artificial barriers are usually installed near property lines, with the intent of establishing a modest “prairie dog-free buffer zone.” Select the best location possible by staying near the property line, considering existing topography and the type of native vegetation that will be used to create an aesthetically appealing permanent barrier.

2. Prairie dogs must be removed from the buffer zone, making certain that coteries do not overlap the barrier.

3. An olive-colored vinyl barrier, 36 inches tall with a grommet every 3 feet on both the top and bottom is erected. A 3 inch trench can be formed to place the bottom of the vinyl into but is not necessary in all situations, remember that light can not show through under the barrier when work is completed.

1. If a trench is used, caution should be given to not trample the excavated soil because it will be reused to backfill the bottom of the barrier.
2. If a trench is not used backfill material needs to be onsite and used to place along the
   soil surface and the bottom of the barrier, like a bead of caulking.

4. The support structure for the artificial barrier needs to be constructed using 5 feet wooden
posts, t-posts, and smooth wire.

1. The wooden post should be placed at both the beginning and end of the structure and every 100 feet between.
2. 1. Wooden posts should be installed to form a 3 feet wide H-post configuration.
   2. This configuration is further strengthened using smooth wire that is tightened from the top corner of each post to the bottom of the other forming an X.
3. T-posts are then placed every 10 feet from the 1st H-post to the last H-post, facing the knobs away from the side that the barrier will be attached to.

5. Smooth wire can then be stretched from one end of the support structure to the other at the height of the barrier to be installed.

1. The wire is wrapped around the end wooden post and stapled, using fencing staples.
2. The wire is then attached to the t-post using fencing ties.

6. The vinyl barrier can now be attached to the support structure on the wind ward side.

1. The top is attached to the wire using hog rings or plastic tie-wraps at each grommet.
2. The bottom is secured using heavy landscaping pins at each grommet to anchor it to the ground before backfilling.

Options:
1. Artificial horizontal barriers can be installed in conjunction with the vertical vinyl barrier to discourage animals from tunneling directly under the structure using 1inch mesh 36 inches wide poultry wire. (see diagram)

1. The wire should be buried 3 inches below the soil surface and extend out from the vinyl 2½ feet overlapping the bottom of the vertical barrier 6 inches on the prairie dog side of the barrier.

2. Native vegetation can than be planted in the area between the artificial barrier and the property line to establish a permanent barrier.

1. Bare-root native shrubs selected for the site are planted 1foot apart in rows that are 2 feet apart, offsetting every other row of plants to create an 8 foot wide barrier.
2. 1. Plastic weed barrier material, (4mil), is placed on the ground before the shrubs are planted and removed after the first 3 to 5 years.
   2. Mulch is placed over the weed barrier.
   3. Shrubs are watered weekly, during the growing season, or as needed for the first 2 to 3 years.
   4. Shrubs are weeded once during the growing season and pruned early in the dormant season for the first 2 to 3 years. Pruning encourages bushier growth.
3. Other native vegetation is currently being experimented with.
4. 1. Vines work well along fences
   2. Common cattails and coyote willows work well along ditch banks.

3. A mix of native tall grasses and wildflowers can also be established between the artificial and living barriers.

1. Grasses should be mowed twice during the growing season until established.
2. Wildflowers should not be added until after the grasses are established.

4. Terrestrial predator enhancements and raptor perches can be strategically placed along the
prairie dog side of the barrier to, in theory, increase the likelihood of predation along the barrier.

1. Terrestrial predator enhancements consist of a cluster of bare-root native shrubs planted in any configuration.
2. 1. The cluster should be enclosed with a 1 inch mesh, 36 inch high poultry wire structure, supported on t-posts at each corner to prevent herbivory.
   2. A smooth wire should be stretched across the top of the poultry wire to add support to the enclosure.
3. Raptor perches can range in height up to 20 feet.
4. 1. Dead trees that have a large branch near the top to support a cross member are installed as raptor perches. We typically use crack willow.
   2. 1. Cross members are attached using smaller limbs from a tree.
      2. Cross members are attached near the top of the branch extending straight across to the trunk of the tree.
   3. Native trees can be planted near the artificial perch to some day replace it.
   4. 1. Trees should be mulched and watered the first couple of years.
      2. A wire structure should be erected around the tree, as described in 4A above, to protect the tree.

   5. Neighboring private property owners should also be encouraged to construct a parallel barrier
   along their property line using native vegetation or a solid 3 feet to 4 feet structure.

   6. Construction of vertical artificial vinyl barriers onto existing fences taken from the City of Boulder:

   1. Excavate a narrow (width of a Pulaski blade) shallow (approximately six inches) trench in the soil directly under the strands of the existing fence. This can be done with a pick or pick-maddock in most areas. Be careful not to hit the fence wire while using the tools to prevent unpredictable recoil of the tool from fence wires. Put the excavated material on the side of the fence where you will have access to it once the barrier is in place as you will need to bury the fabric. In cases where the fence has not yet been constructed, a trencher can be used to excavate the furrow.
   2. Unroll a length of visual barrier material along the fenceline. You may need to cut the material if there is no available wooden post at the end of the roll, or if you are unable to stretch the material to an adjacent wooden post. Next, unroll a strand of smooth braided wire which will be used as the anchor wire along the bottom of the barrier. The wire should be at least six to ten feet longer than the piece of visual barrier material. The extra wire is necessary for attaching both ends to wooden posts.
   3. Attach the smooth wire to the beginning and ending wooden posts. Then stretch the wire with a fence stretcher tool until it is fairly taut and secure the wire to the posts as close as possible to the bottom of the trench.
   4. Measure the height of the visual barrier when it is attached to the smooth wire in the trench. If no existing strand is available at the top or within one inch of the top of the fabric, it will be necessary to place a strand of HTF wire at the right height. Secure the HTF to two end posts, but do not staple the wire to the correct height on the wooden support posts until step 7.
   5. Secure long rubber pieces over the staples on wooden posts to prevent abrasion of the fabric.
   6. Make an accordion pleat at the end of the visual barrier fabric, overlapping 8-10 inches four to six times. The end of the material should be folded on top of the leading edge. This thickened section will be secured to a wooden post with staples. Making sure the bottom edge of the fabric is flush with the ground, hammer the staples first through the top grommet and into the fence post. Then secure the bottom grommet. Several staples may be hammered between the top and bottom to secure this anchor point. Note: the staples should be oriented vertically (i.e., one tine above not next to the other).
   7. From this point the fabric will be attached to each of the wooden posts in succession. Someone can begin attaching the grommets along the fabric hems to the appropriate wires with plastic cable ties or hog rings. (If a new HTF strand was used, you may now raise the wire to the appropriate height and staple it to the wooden post with the fabric already attached.) Two people may then tighten the fabric until slack is removed and staple the fabric to fence posts. Use duct tape to reinforce the fabric in palaces where it cannot be stapled at a grommet. In some cases the crew may feel that it is necessary to better secure the barrier to the fence post. Place a strip or square of rubber over the fabric for protection and stapled through the rubber into the post.
   8. At the end of the length of fabric, fold the fabric over and secure it as described in step F.
   9. In places where the bottom wire does not sit on the bottom of the trench, use rebar stakes to sink the wire to the trench bottom. The wire may be stapled to the base of the wooden posts to further secure it.
   10. Fill the trench with the excavated material so that no light shows through the fence. If necessary, fill any prairie dog holes along the fenceline with soil and rocks. It may be necessary to take fill from the field to close gaps where light penetrates under the barrier.
   11. Each of the wood droppers on HTF fence is secured with metal clips. The ends of these clips can tear the fabric. As a last step, bend the ends of the clips away from the fabric so they do not poke holes in the material

   Supplies needed to construct artificial vinyl barrier:

   Tool List Fence stretchers Fence pliers Lineman pliers Framing and sledge hammers Shovels Rakes McLeods File to sharpen tools Knives or scissors (for cutting fabric) Hog ring Pliers T-post pounder Post hole digger If Trenching Pulaskis Pick, Pick-Maddock Safety Equipment Gloves Glasses

   Equipment List Visual barrier material Tie wraps or Hog rings Smooth wire Fencing staples Fencing t-post ties Heavy landscaping pins T-post Wooden post Backfill material HTF Equipment (attaching to existing fence.) Ratchets Ratchet tool Crimper Nicopress sleeves Spinning jenny and wire

   Source for vinyl barrier material:

   Mark Young
   P.O. Box 750245
   Houston, TX 77275-0245
   Phone: 1-800-231-6074