How To Build Fence With Wildlife In Mind

Wildlife Friendly Fenceshaystackfencechildren’splay r fencewildlife access towater and travelcorridorlay-downfencePlace crossings, jumps, opengates and other wildlife openingsin appropriate locations. Deer, elkand pronghorn are more likely touse openings at fence cornersthan in the middle of a fence run,unless there is cover, habitator natural corridors or trails toattract them through. Intermittent openings should be placedwhere animals naturally travel: inriparian corridors, along gulliesand ridges, and on existing gametrails.A fence of any height is moredifficult to cross when placedacross a steep slope. As groundslope increases, the distancean animal must jump to clearthe fence increases considerably (See illustration at left). Forinstance, a 42” fence may bepassable on level ground, but aslope of only 10% increases theeffective fence height to 48.6”; aslope of 30% increases effectiveheight to 62”, and on a 50% slopeanimals encounter an obstacle75” high. Fences on steep slopesbecome nearly impossible foranimals to jump without injury.Tailor your fences to specific needs andallow wildlife access to water, importanthabitats, and travel corridors.Look for wildlife trails andwatch for seasonal patterns.Provide wildlife access toriparian habitats, waterholes and other high qualityhabitats.Provide passage alongswales, gullies, ridges andstream corridors. Use the appropriate fencedesign for each activity.On slopes and in naturaltravel corridors, plan forwildlife crossings.

Friendly DesignsThe ideal wildlife friendly fenceshould (1) allow relatively freepassage for animals to jump overand crawl under, and (2) be highlyvisible for both ungulates andbirds. You can combine or tailormany of the ideas presented herefor your specific situation.Fences should be low enoughfor adult animals to jump, preferably 40” or less, and the top twowires should be no less than 12”apart. Deer and elk easily tangletheir back legs if the top wires arecloser together. The bottom wireor rail should be high enough forpronghorn, calves and fawns tocrawl under, at least 18” from theground. Increasing visibilityusing a top rail, high-visibility wire,flagging or other visual markerscan help ungulates and birds,such as hawks, owls and swans,better navigate fences.Wildlife Friendly IdealWildlife friendly fences should be low enough for adult animals to jump,high enough for animals to crawl under, and minimize the chance oftangling. Montana Fish, Wildlife and Parks (FWP) recommends:A top wire or rail preferably no more than 40” above the ground, andabsolutely no more than 42”;At least 12” between the top two wires;At least 18” between the bottom wire or rail and the ground;Smooth wire or rail for the top, smooth wire on bottom.No vertical stays;Posts at 16.5-foot intervals;Gates, drop-downs, or other passages where wildlife concentrateand cross.Using smooth wire – barblesswire, high-visibility tape or braid,or high-tensile electric wire – forthe top and bottom strands willprevent snagging and injuries.In wildlife migration areas,drop-down fence, lay-down fenceor crossings can be used forseasonal wildlife passage.Ideal Wildlife Friendly FenceIncrease visibility with a PVC cover,high-visibility wire, flagging, or a top rail.smooth12”barbedbarbed40” preferred(42” maximum)smooth18”The friendliest fences are very visible andallow wild animals to easily jump over orslip under the wires or rails.

Friendly DesignsVisibilityThe best way to prevent afrightened deer or low-flyingswan or grouse from colliding witha fence is to make it highly visible.One solution is a top rail, howeverheavy snow build-up along therail can sometimes deter elk anddeer from crossing, so a roundedrail that will shed snow moreeasily is preferable.The least expensive solution is tosimply hang flagging, or othermaterials along the top, althoughmany materials can fade or belost and need regular replacement.High visibility helps wildlife negotiatefences. It is especially important ingrasslands and near creeks andwetlands to protect low-flying birds, suchas grouse, owls and swans. PVC pipe,flagging, and white wire or tape all helpwildlife see fences.Jay KolbeFor wire fences, a less expensivealternative is to slip sections ofsmall diameter PVC pipe over thetop strand. High-visibility wire isalso available in many forms –tape, braid and polymer-coatedwire – many of which can beelectrified if needed. White wire isthe most visible to wildlife.FWPHIGH VISIBILITY Fence

Friendly DesignsVisibility (continued)Christine PaigeAnother relatively inexpensivealternative is offered by theSutton Avian Research Center inOklahoma using “undersill” or trimstrips of white vinyl siding cut into3” pieces. The undersill siding stripshave a lip that can be snappedonto barbed-wire fence, and thevinyl strips can be easily cut withtin snips or a miter saw. The sidingpieces are lightweight and durable,and a long run of fence can bemarked quickly and easily.Durable Markers for Wire FenceSeveral 12’ strips of “undersill” or trim strips of white vinyl siding,available at home hardware centers.Christine PaigeCut strips to 3” lengths. Use tin snips for small projects, or use a 10”miter saw with a 200-tooth blade to cut up to eight pieces at a timefor larger projects.One 12’ siding strip yields 48 pieces.Christine PaigeSnap pieces onto top and middle wires: at least four pieces on thetop wire per fence section, and three pieces on the middle wire persection.Durable Markers on Wire FenceDurable and lightweight fence markerscan be cut from strips of vinyl siding trim.The trim strip has a lip that easily snapsonto fence wires.vinyl markerssmooth or barbed18”10

Friendly DesignsSites with Low or Seasonal Livestock UseNot all situations require a fivestrand barbed-wire or woven-wirefence. Smooth wire fence, varioustypes of post and rail fences, andtemporary or moveable electricfences can be used for seasonalpastures, horse pastures andmany other situations with low orintermittent livestock use.3-StrandSmooth Wire FenceChristine PaigeUse 3 strands of smooth (barbless)wire. High-tensile wire is effectivefor light livestock control. Top wire 40 to 42” high;Center wire 30” above theground;At the Blue-eyed Nellie WMA nearAnaconda, the Anaconda Gun Club,local landowner Wayne Ternes, and FWPpartnered to install a bighorn-sheepfriendly fence. Replacing old four- andfive-strand barbed-wire, the new fencesare three-strand smooth wire with a 39”top wire and 16” bottom wire. Bighornsheep now readily hop over and duckunder the fences.Bottom wire 18” above theground;Preferably, no vertical stays;Christine PaigeWood or steel posts at16.5-foot intervals.3-Strand Smooth Wire Fence16.5’wood or steel postsall smooth wires40” preferred(42” maximum)28-30”18”11

Friendly Designs(a t-post pounder can be usedif ground is soft);SEASONAL ELECTRICWIRE FENCEUse treated wooden posts forbracing at ends and center;A flexible electric fence thatallows passage for elk and otherungulates can still be effectivefor livestock, particularly horsesbroken to electric fence. It canbe laid down seasonally to allowfree wildlife passage. This fenceis useful for keeping stock out ofsensitive habitats or for shortduration grazing where permanent fencing isn’t desired. lace a top wire of conductivePhigh-visibility tape, braidedwire or polymer-covered wireno higher than 42” height,electrically charged (mediumtensile 12-guage plasticcoated wire is satisfactory). lace a second groundedPstrand of high-tensile wireat 30”; re-drill 72” x 1” heavyPfiberglass posts;Attach strands to fiberglassposts with wire clips that canbe removed when fence islaid down;Jay Kolbe rive posts 24” into theDground at a 32-foot spacingJay KolbeThis 2-wire seasonal power fence can beused where stock are broken to electricfence. Wooden posts brace the ends.The fiberglass posts can be laid downwhen the fence is not in use.12Use insulators for attachinghot top wire to wooden posts;grounded wire can be stapledor clipped directly to woodenposts.Use a solar electric energizer(size and placement dependson the run length of fence).To work properly, this fenceneeds to flex as elk and otheranimals pass over it. Install asfew rigid post supports aspossible, and use the minimumrecommended wire tension.Placing the energizer toward themiddle of the fence will afford thegreatest electrical efficiency.

Friendly DesignsCollaboration in the BlackfootThe vast majority of fences on the property arebuilt with three or four barbed-wires hung fromsteel posts. Though these designs worked wellon some parts of the ranch, they often failedwhen built across elk migration corridors. Oneparticularly troublesome stretch of fence ran for aJuanita Vero“Zero maintenance – it’s been amazing,” saysJuanita Vero of her new stretch of electric fence.Juanita, the fifth generation owner and managerof the E Bar L guest ranch in the Big BlackfootValley, has fixed her share of damaged fence.On the E Bar L, eighty head of horses share4,000 acres of range with large numbers ofdeer and elk.When I asked my 91-year-old grandfather ifthe fence project was a success, he quipped,“We wouldn’t do it if it wasn’t gonna work.”– Juanita Veroground wire, hung at 40”, is standard 12.5 gaugehigh-tensile steel.Juanita VeroThe new fence works well. “Elk go right throughit,” Juanita says. “When nobody is putting pressure on them, even the big bulls go under with noproblem.” It holds their herd of horses well, too,although Juanita remains uncertain of whetherthe fence would adequately contain other typesof livestock.half mile along one edge of an irrigated haypasture. Elk crossed the fence on their dailycircuit between the Blackfoot River and a standof timber, frequently causing damage. The Veroswere ready for an innovative approach tofencing, and they sought the help of Jay Kolbe,Montana Fish, Wildlife and Parks Biologist, tohelp design and fund the project.Under an agreement to evaluate the design,and splitting costs and labor, FWP and theVeros built a two-wire electrified fence on 1”diameter fiberglass posts spaced approximately32’ apart. The top wire, hung 48” off the ground,is a high-visibility, plastic-sheathed, conductivewire designed especially for horses. The lowerThe Veros have experimented successfully onother parts of the ranch. They use temporaryelectric fence to divide pastures into smaller units,allowing them to better control the way their herdgrazes. Because this polywire fence is a singlestrand design, it is highly permeable to wildlife.Although most fence on the property remainsbarbed-wire, and the cost of replacing it withelectric fence is high enough to be prohibitive,Juanita is upbeat about the potential for futureinnovation: “The best thing of all is that we havegood agency people like Jay to work with, and ahistory of collaborative conservation in theBlackfoot Valley to build on.”– Bryce Andrews13

Friendly DesignsMOVEABLE ELECTRICWIRE FENCEThe design can be tailored to yoursituation, but a simple fence canbe constructed using high visibilitytape or “turbo wire” and fiberglassposts or plastic-insulated steelposts. A moveable fence can useeither a single hot wire (whenthere is sufficient moisture for anadequate ground) or two wires,the top one hot, the lower wiregrounded. Moveable posts onthe market include designs withhooked or pigtail tops for quicklystringing wire, and a tread-in foot.These can be rapidly set up andmoved as needed.Use 40” to 42” fiberglass orplastic-insulated steel posts,designed with hooks or loopsfor wire and tread-in spikes atthe foot;Place one to two strands ofhigh-visibility tape orpolymer-covered turbo wire.If two wires, the top should behot, the lower wire grounded.Top wire should be no higherthan 42”; lower wire no lowerthan 18”;Use a solar electric energizer(size and placement dependson the run length of fence).14Christine PaigeA moveable electric fence can beused for short-duration grazing, tokeep stock out of sensitive areassuch as wetlands, or for othersituations where livestock needto be temporarily controlled. Thisfence works well for stock thathave been previously broken toelectric fences.A temporary electric fence can be used tokeep stock out of sensitive areas and iseasily negotiated by most wildlife.Tips on Electric FencesMost electric fence problems arecaused by poor grounding. Follow the manufacturer’s specifications for grounding the energizerand fence for your fence typeand conditions. The number ofground rods needed may vary;a maximum reading of 0.2kv ona volt meter in dry conditionsindicates an adequate ground.Wooden and steel fence postsrequire insulators for attachinghot wires; ground wires can bestapled or clipped on directly.Fiberglass and plastic line postsdo not need insulators, but dorequire special clips for attachingwires. Check the fence regularlyto be sure it is charged.Seth Wilson

Friendly DesignsPost and Rail Fence:A post and rail fence is highlyvisible to wildlife and can beconstructed for situations with orwithout livestock. Rail fences caneither use a top rail with wiresbelow, or two to three rails total.A two-rail fence is preferable to athree-rail fence for wildlife. Unlessthe fence is quite low, use rounded poles for the top rail, ratherthan a square or split-rail, toprevent too much snow build-upin winter, which can deter elk anddeer. Also, unless the fence iseasily jumped and there is ampleclearance underneath, boards orplanks are not recommended asthese can create a visual barrier.Christine PaigePost and rail FenceUse pressure-treated 6’ to 8’posts, spaced 10’ to 14’ apart.Second wire should be at least12” below top rail.Use pressure-treated poles fortop rail, placed no more than40” above the ground.OR place pressure-treatedpoles for lower rails, thebottom rail placed with at least18” clearance from the ground.Place smooth lower wires at18” and 28” above the ground.Post and Rail Fence40”18”Post and Wire Fence12”all smooth wires40”18”15

Friendly DesignsWORM FenceAlthough worm fences are moreeasily negotiated by wildlife thanthree-dimensional jackleg fences,they can still be a barrier tofawns, calves and other animals.Other drawbacks include rotting,the excessive number of railsneeded, the considerable spacethe fence takes up on the ground,and maintenance to rebuildcollapsed sections.Worm fence is simply constructedof rails stacked alternately on topof one another, with the rails interlocked like laced fingers wherethe ends meet. The fence zigzagsto give it stability, and it can beused where posts can’t be driveninto the ground. These fencesare usually only two to three feethigh, and are most often used inChristine PaigeWorm fences, also called zigzagor snake fences, were used byearly settlers, especially whereclearing homesteads of timber,because they are easy toconstruct and require no posts.Worm fences are still popular insome areas for their rustic nature,especially as boundary fences.They are not used to containlarge livestock.mountainous areas where localtimber is readily available andthe terrain tends to be rocky anduneven. If you use a worm fence,create openings for wildlife tocross by intermittently droppingrails to the ground. se three to four stacked railsUper section, 8’ to 11’ long; ogs or split rails can beLused. Rails split in a triangularmanner add stability;Set the ends of each bottom railon a rock or short log slightlyabove the ground to postponedecay;I nterlace the rails at joints at a30-degree angle;16A low worm fence is easily hopped bymost ungulates. Drop the top rail to theground every few hundred feet to allowsmaller animals cross. tack rails only up to a 2’ to 3’Sheight;I f extra stability is needed,fasten rails together with 6”nails or spikes, and drive 4’lengths of 1/2” rebar into theground on either side of thejoint, flush with the top rail;Drop rails to ground every 400’,and in swales and at streamcrossings for easy wildlifepassage.

Friendly DesignsChristine PaigePost and Rail Fence:Sites with High or Continuous Livestock UseMost livestock pastures do notrequire a five- to six-strandbarbed-wire fence. In manysituations, a three- or four-strandbarbed-wire fence, a combination of smooth and barbed-wire,or a high-tensile electric fencewill work well for livestock control,particularly if the pasture qualityinside the fence is as good orbetter as outside the fence.Sheep, bison and cows withcalves may require moreimpermeable fence for control. Ifyou must use fences with wovenwire or more than four wiresfollow these tips: onsider the placement of theCfence perimeter carefully, andlimit the extent of impermeablefence whenever possible. void excluding wildlife fromAstreamsides and water sources, or cutting off migration andtravel corridors. eep the fence height to aKmaximum of 40” to 42” and create periodic crawl-openings forfawns and calves by raising thebottom 18” from the ground,placed where animals typicallytravel. void topping woven wireAfences with barbed-wire. Inany situation, allow 12” betweenthe top wire and the next wirebelow – whether barbed orwoven wire. reate seasonal openingsCusing lay-down fence sectionsor gates to open the fenceduring months when stock arenot present.17

Friendly DesignsA four-strand fence for sheep canhave a top wire no more than 32”high. Allow at least 10” betweenthe top two wires. (A lower fenceis easier for deer and elk to jump,and so the 10” spacing betweentop and second wires will usuallybe adequate.) The bottom wireshould be smooth wire and atleast 10” above the ground.4-STRAND BARBED-WIRE FORCATTLE OR SHEEPWoven-wire fences block wildlifepassage, particularly for fawns,calves, pronghorn and mediumsized animals unable to jumpover fence. On cattle and sheeprange, it is possible to use a fourstrand barbed-wire fence thatcontrols livestock but still allowsfor passage of pronghorn, deer,moose and elk.Top wire height 32” maximumfor sheep, 40” to 42” for cattle;or 38” for both sheep andcattle.For cattle, use a wire spacing of18–22–28–40/42 inches. The topwire should be at 40” to 42” orless. Allow 12” between the toptwo wires and 18” between thebottom wire and the ground. Usea smooth bottom wire.At least 10” to 12” between thetop two strands. bottom smooth wire, at leastA10” above the ground for sheepor sheep/cattle fence, and 16”to 18” for cattle.SHEEP AND CATTLE 4-STRAND BARBED-WIRE FENCE(Adapted from Wyoming Game and Fish Dept., 2004)Recommended Wire Heights Above the GroundCattleSheepSheep & CattleTop wire40” to 42” barbed32” barbed38” barbed2nd wire28” barbed22” barbed26”

fence types caused the most problems. Here are their key findings: Snared and Entangled 90% of these carcasses found 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