Living with wolves
What is fladry?
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Fladry is one of the simplest techniques for deterring wolf activity. It consists of brightly-coloured (normally red) flags of material hung from lines or fences.
Wolves are naturally nervous of new and unusual stimuli in their environment and are deterred from crossing boundaries with fladry even where they fully are capable of getting through.
EVIDENCE OF EFFECTIVENESS
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A major field trial of fladry took place over the summers of 2004 and 2005 in Michigan, on 8 sheep and cattle farms whose land overlapped with wolf territories. On farms where fladry was installed for the study, there was a reduction in the number of wolves that made it inside livestock pastures - on the two occasions where they did, the fladry had been improperly installed or maintained.
The results of this and previous studies concluded that fladry is effective for up to 75 days at deterring wolves from entering livestock pastures. After this amount of time, wolves normally become accustomed to the fladry and are no longer deterred.
IS FLADRY RIGHT FOR MY LAND?
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The cost to install fladry from scratch and maintain it around a 150ha farm was estimated at $4,392 per year including labour (in 2004), and required 8.5 hours per km for one individual to install and 1.6 hours per km per week for regular maintenance. It is therefore advised that you should consider where losses from wolf depredation in your area outweigh the expense of fladry before installing it.
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Due to the short-term effect and expense of fladry, researchers have suggested it is best used minimally, at times and in areas where protection is most important - for example, to protect cows/ewes and their young during the calving season, when they can be confined to smaller areas.
However, other techniques can be used to reduce maintenance and make fladry more effective in the long-term (see below).
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From the time we started [using fladry] up to now, we've had zero wolf depredations. I think the fence has a lot to do with it.
- Carey Dobson, rancher near Apache National Forest, USA -
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Tools such as fladry can be very effective by exploiting natural predator behaviors like fear and avoidance.
- Nathan Lance, author of a study on fladry -
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TECHNIQUES TO IMPROVE FLADRY
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One of the issues with fladry that necessitates regular maintenance is ‘coiling’, where the flags of material become wrapped around the line and therefore don’t hang freely as needed and open up gaps in the fladry line through which wolves can pass.
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New designs for fladry to reduce this problem were tested at the Predator Research Facility in Utah in 2014. The results showed that investing in fladry made from marine vinyl - a heavier and, although more expensive, also more durable material - as opposed to nylon, reduced coiling and was similar in cost in the long term.
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The simplest yet still effective way to reduce coiling was to tie a knot in each fladry strip directly beneath the line. This could easily be applied by current users of nylon fladry.
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Electrified fladry, known as ‘turbo-fladry’, can solve the issue of wolves becoming unafraid of fladry, as they receive an electric shock when coming into contact with it and learn to associate attempting to cross with pain and discomfort.
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This was confirmed by a study on in 2010, which found that fladry with an electrified wire running close to ground level was 2-10 times more effective at deterring captive wolves from approaching a deer carcass. A subsequent field study in Montana also found that no wolves entered pastures bordered by turbo-fladry.
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Turbo-fladry was more expensive than other fladry at $2303 for the first km and $2032 for each additional km, and required 31.8 person-hours per km to install. In over a year of the study the electric system failed 18 times, taking on average just under an hour to fix.
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The main issue with the use of turbo-fladry was the expense - however, 83% of the ranchers participating in the survey said they would continue to use the turbo-fladry if certain conditions, such as cost-sharing, were met.
© Nathan Lance
Davidson-Nelson, S., & Gehring, T. (2010). Testing fladry as a nonlethal management tool for wolves and coyotes in Michigan. Human-Wildlife Interactions, 4(1), 87-94.
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Young, J., Miller, E., & Essex, A. (2015). Evaluating fladry designs to improve utility as a nonlethal management tool to reduce livestock depredation. Wildlife Society Bulletin, 39(2), 429-433. http://dx.doi.org/10.1002/wsb.531
Read it here (requires institutional login)
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Lance, N. J.; Breck, S. W.; Sime, C.; Callahan, P.; and Shivik, J. A., (2010) Biological, technical, and social aspects of applying electrified fladry
for livestock protection from wolves (Canis lupus), USDA National Wildlife Research Center - Staff Publications, 1259.