Tuesday, 28 July 2015

Misled about snaring?

GWCT fox snare with 'breakaway' device
In an article in the Veterinary Times, June 2015, Professor Ranald Munro exhorted the veterinary profession to speak out against the use of snares.  Jonathan Reynolds BSc, PhD, Head of Predation Control Studies at the GWCT, submitted a response arguing that Munro had given a very misleading synopsis of the subject.

There has been a lot of scientific research on snares lately.  Jonathan’s article summarises how the subject has developed, and indicates where to find the evidence. It was first published in Veterinary Times 45 issue 30.

Non-lethal intent

Fox snares are not intended to be lethal devices.  Since 1981, when self-locking snares were banned by the Wildlife & Countryside Act, the intended function of fox snares has been to hold the animal alive until it can be humanely dispatched.  Perhaps surprisingly, the captured fox is at little risk (less than 1%).

Wildlife scientists like myself rely on this when we use snares to catch foxes (and other canids) for radio-tagging studies.  For this purpose snares are uniquely effective, injuries are rare, and behaviour after release appears to be normal.  You might argue that this view is biased because we are motivated to ensure the welfare of our study animals and take unusual care.

The veterinary experience of snares, in contrast, typically consists of animals brought for treatment which have been injured in snares.  This brings a different bias, towards snares used unwisely close to housing, captures of domestic pets, and cases involving very poor welfare in wild animals.

In 2004, the Independent Working Group on Snares (IWGS)1 brought together expertise from snare users, animal welfarists, veterinary practice and scientists.  The consensus view was that while snares were an effective tool, they could also cause immense suffering in some circumstances.

From experience, the group felt it could identify aspects of snare design and working practice that led to bad outcomes.  They encapsulated this knowledge in a Code of Practice (CoP),2 which Defra published as its own.  In essence the message was ‘Limit your use of snares and use them with great care’.

Message not received

The Defra study3 referred to by Ranald Munro sought to estimate the extent of snare use across England and Wales, by telephone survey across a random sample of landholdings.  This uncovered the important fact that almost half of snare users were not gamekeepers as expected, but farmers.

As a group, gamekeepers were more familiar with best practice recommendations than were farmers, reflecting where educational effort had been directed.

Nevertheless, it was clear that poor working practices persisted in both groups, and at the date of the study (2009-10) no UK snare manufacturers had yet produced snares that met CoP recommendations.  Why had the message not got through?   I suggest two main reasons.

First, organisations associated with game management or shooting promoted this Code to gamekeepers through training courses and other material; but neither Defra, nor animal welfare organisations, nor farmer organisations did anything to promote the Code.

Second, the CoP was based on expert views, but many snare users also considered themselves experts and were unconvinced that a change in practice was necessary.  To persuade them, the CoP needed to be evidence-based.

How good could it be?

In a second section, the Defra study tested the humaneness of fox snares when used by an experienced technician in a field situation; injuries were independently assessed post mortem by veterinary pathologists, and compared against international humaneness standards for restraining traps.

Best practice was followed.  Provided a CoP–compliant snare was used, humaneness standards for restraining traps were met for foxes.  (For non-target species, the numbers caught were insufficient to judge).

Much more extensive field evidence came from a contemporaneous study by the Game & Wildlife Conservation Trust (GWCT)4, in which a thoughtfully re-designed snare was trialled by 34 gamekeepers in a 2-stage, 18-month study, in comparison with whatever snare design they previously used.  No attempt was made to influence their working practices.

The study showed that the risk of injury or death greatly increased if the captured animal could entangle the snare with nearby objects.  For foxes, the risk was 40% when old-style snares were used and entanglement occurred, but less than 1% when entanglement did not occur and improved snares were used.  Entanglement can be entirely avoided by following the working practices recommended in the CoP.

Snares are certainly not ‘totally indiscriminate’ – it is amazing how such a sketchy device can be made to outline where in the landscape a fox will put its head – but there is an attendant, lower risk of catching certain other species.

In an ideal snare, those non-targets would quickly self-release if caught; or, if held until the snare is inspected, would be un-injured and fit for release.  The GWCT study showed that non-target captures could be substantially reduced through hardware design, and that if experimental snares and good working practices had been used exclusively, the underlying risks of injury or death would have passed trap humaneness standards for non-targets as well as for foxes.

The actual incidence of poor welfare will obviously reflect both the density of non-targets and the intensity of snare use: it’s a balance judgement to be made for each situation.

It’s ironic that the non-target species most at risk in terms of numbers caught and injuries sustained was the brown hare; and that a significant cause of injury or death for hares held in the snare was predation by foxes.

It grimly illustrates the difficulty of finding wholly satisfactory solutions to wildlife issues.  The brown hare is a Priority Species under the UK Biodiversity Action Plan because of a long-term decline in abundance.

In population terms hares benefit dramatically from fox control, even when that included the use of old-style snares5.  The GWCT’s experimental snare allowed 68% of captured hares to self-release, and a further 24% were judged fit for release when found in the snare.

It is during the breeding season (for hares and other prey), when fox control by shooting is limited by tall vegetative cover, that snares come into their own.  Despite their shortcomings, snares have a role in wildlife management that we cannot yet replace.

GWCT took a constructive approach to an evident problem, and as a result we now have a greatly improved snare design which meets trap-testing standards, and sound best practice guidelines backed with persuasive evidence.

One might have expected all interest groups to embrace these developments, and to join in a renewed educational campaign to drive down the incidence of poor welfare.

Regrettably, animal welfare groups have not done so, nor have they contributed in other ways to constructive progress.  Perhaps the real difference there is idealism versus pragmatism.

Support our predator control team

Please donate so that our dedicated team of scientists can continue their vital work.

£67 – covers the cost of attending a meeting with Defra or other bodies, to present our evidence and help shape policy

£176 – buys a trail camera which can be used for several years to monitor traps and other sites

£480 – pays for a day’s labour and equipment for our three person predation team, producing the science that can influence policy and practice for years to come

Please click here to donate >


1.    Defra (2005) Report of the Independent Working Group on Snares.
2.    Defra (2005) Defra Code of Practice on the Use of Snares in Fox and Rabbit Control.
3.    Defra (2012) Determining the extent of use and humaneness of snares in England and Wales.
4.    Short, M.J., Weldon, A.W., Richardson, S.M., Reynolds, J.C. (2012) Selectivity and injury risk in an improved neck snare for live‐capture of foxes.  Wildlife Society Bulletin 36(2): 208-219
5.    Reynolds, J.C., Stoate, C., Brockless, M.H., Aebischer, N.J., & Tapper, S.C. (2010)  The consequences of predator control for brown hares (Lepus europaeus) on UK farmland.  European Journal of Wildlife Research 56: 541-549

Jonathan Reynolds BSc, PhD is a scientist at the Game & Wildlife Conservation Trust (GWCT) with more than 30 years post-doctoral experience.  He leads research on how mammalian predators and pests are managed in the conservation of game and other wildlife.

No comments:

Post a Comment