Scottish Animal Welfare Commission: report on the use of rodent glue traps in Scotland

Ethical analysis and critical issues

Broadly speaking, the issues raised in evidence received by the Commission fell into the following categories: (i) reasons for using glue traps; (ii) animal welfare impacts of glue traps on captured animals, including methods of dispatch; (iii) non-target captures; (iv) alternative rodent control methods; (v) ethical considerations; and (vi) legislation in other countries.

Reasons for using glue traps

Most respondents acknowledged that measures were necessary to control or eradicate rodent incursions, particularly to food preparation or medical facilities. The British Pest Control Association (BPCA) raised public health concerns:

"Rodents carry and transmit pathogenic microorganisms (and therefore disease). Failure to act quickly in a high-risk environment can result in sickness, distress and death."

The Royal Environmental Health Institute of Scotland (REHIS), while recognising the need for control of the use of glue boards in pest control, believed that there were "cases of last resort, where other control measures have failed and there is no alternative to the use of glue boards."

Science and Advice for Scottish Agriculture (SASA) commented:

"It is difficult to know where they are 'essential', however it is worth considering that rather than being a specific location it might be argued that these traps may be necessary at any location where rats need to be removed quickly and where preferred alternatives are failing to work or are inappropriate.

The kinds of places where rodents would need to be removed quickly might be hospitals and other health care facilities, food manufacturing, pharmaceutical manufacturing and food preparation, where there are potentially serious consequences from contamination. It might also be imperative to quickly remove them from anywhere with critical infrastructure involving wiring and electrics where there is either a danger of gnawing damage or of equipment shorting and, in extremis, fire (perhaps a data centre or a power station control room?)"

Some animal welfare stakeholders accepted that there were currently some practical reasons for opting to use glue traps – for example, the Universities Federation for Animal Welfare (UFAW) stated:

"Glue traps offer some advantages over other methods of lethal rodent control; they require little technical skill to use (although skill will be required to humanely kill a trapped animal), can fit where other devices cannot, are free from toxic substances and may be used as a method of demonstrating the presence of or assessing the extent of an infestation."

All stakeholders acknowledged, however, that glue traps cause animals to suffer. Some believed this was unavoidable due to the urgent necessity of controlling rodents in certain situations. Others maintained that glue traps could not be justified under any circumstances and that alternative methods were always to be preferred.

Conclusion – reasons for using glue traps

There are public health concerns in certain high-risk situations that clearly require effective and rapid pest control in order to reduce the spread of disease. However, the Commission is not convinced that evidence exists supporting the view that glue traps are genuinely the only method of last resort.

Animal welfare issues

For the pest control industry, the BPCA acknowledged that glue traps could cause animal suffering and believed they should only be used as a last resort by commercial operators such as BPCA members, in accordance with the Pest Management Alliance (PMA) Code of Best Practice for the Humane Use of Glue Traps (PMA, 2017a).

HSI UK described extreme suffering in individual animals, noting that the number of animals affected is not known:

"Every year across Scotland and the rest of the UK, glue traps, widely available for as little as 99p, cause untold numbers of trapped rodents to suffer horrific injuries and an agonising and protracted death from starvation, dehydration, suffocation, exhaustion or stress. Animals caught on these devices are known to break and dislocate limbs, tear off fur and skin, and even attempt to gnaw off limbs in order to free themselves."

Two scientific papers were referenced by several of the animal welfare advocacy groups to substantiate their observations. Fenwick (Fenwick, 2013) reviewed three experiments noting physical observations of rodents caught in a glue trap. All three experiments found that rodents became fully entangled in the glue, with feet, body and head eventually becoming stuck. It was also reported that the animals' mouths became glued shut as a result of trying to chew themselves free from the trap. Two of the experiments observed the animals repeatedly defecating and urinating while one reported that the animals had eye damage and, where fur was torn away, raw skin patches.

Mason and Littin (Mason and Littin, 2003) stated that glue traps:

"…seem to have the same major welfare costs as leghold traps: instant and prolonged distress and trauma, followed by dehydration, hunger and sometimes self-mutilation when animals are held trapped for long periods."

UFAW concluded:

"UFAW's opinion is that the severe welfare impacts of glue traps both on target and non-target species rarely if ever outweigh their benefits and therefore that their use should not be permitted for the control of any vertebrate species. Unlike snap-traps where death is rapid if the trap functions correctly, immediate, and long-lasting severe suffering is virtually guaranteed with glue traps and therefore snap-traps should be considered a more humane alternative method where rodents must be caught and killed."

Glue traps are restraining traps, meaning that users should expect to find the trapped animal alive and be prepared to dispatch it quickly and humanely. However, some respondents pointed out that advertising and packaging do not give any advice on the best method, and nor does the industry code which refers to suitable training. A blow to the head is often intended to produce instant death, but it was suggested that many people would not be able to do this effectively. Likely reasons for failure to dispatch humanely included fear, health hazards and squeamishness. HSI UK commented:

"Since many glue traps are supplied without adequate instructions to inspect traps frequently, users may be unable, or unwilling, to check them within appropriate intervals. Trapped animals may therefore experience prolonged and unnecessary suffering, taking hours or even days to die."

HSI continued:

"A UK YouGov opinion poll commissioned by HSI UK in 2015 found that over half of respondents said they either would not know what to do with a trapped animal or would recommend an action that risked committing an offence under Section 19 of the Animal Health and Welfare (Scotland) Act. This included 9% who suggested drowning and 6% who stated that they would leave the animal to die on the trap or would throw the trap away with the live animal still attached."

Many of the same issues were raised by the Wild Animal Welfare Committee (WAWC) and summarised as:

• Mental distress / physical injury when struggling to escape, drowning in glue or when being killed: these aspects are indefensible yet unavoidable.
• Inadequate frequency of trap inspection (including possible starvation): glue traps cannot be rendered humane by setting a minimum frequency of inspection.
• Inability / reluctance to kill a trapped animal: this means that people may not check glue boards that they have deployed for days or weeks. We are aware of anecdotal reports of live animals attached to glue traps simply being thrown into waste bins.
• Indiscriminate capture: while covers or tunnels could be used, this doesn't obviate the fact that glue boards are indiscriminate by their very nature.
• Trapped animal being attacked or becoming prey to carnivores: this would compound the mental distress and physical injury of the trapped animal and we consider this doubly indefensible.
• Standards of use - public vs professional: while it has been mooted that glue trap use should be restricted to professional operatives, it is hard to imagine how a professional standard can be set given the points above and recognising that the traps are inherently inhumane no matter who sets them.
• Ability for anyone to obtain traps over the internet: See above. If glue traps are proscribed it will be important to ensure that individuals are unable to obtain them from any source.

The National Animal Welfare Advisory Committee (NAWAC) of New Zealand stated that it had recommended regulatory measures for glue traps in New Zealand because of:

• the distress exhibited by rodents caught by glueboard traps;
• the likelihood of an extended period of time between capture and death;
• the inhumane manner of death;
• the possibility of inhumane disposal of live rodents when traps are inspected (animals could be drowned, incinerated or simply thrown into rubbish bins); and
• the existence of practical and affordable alternative methods of rodent control.

SASA described the currently permitted interval of 24 hours between inspections as "certainly too long", but suggested that frequency of inspections involved a balance between welfare considerations and practicality:

"At the very least the industry (PMA) recommendation of every twelve hours should be the bare minimum for consideration but given the likely stress that a captured animal is under I personally consider that is too long and would feel uncomfortable operating such a trap to that timescale. There are likely to be practical problems with reducing the time between checks significantly further as there could be access issues to some premises that are closed at night and it could be difficult for some contractors (in particular sole operators) to undertake round the clock visits every few hours; although that might be viewed as a reason not to glue trap rather than to have long periods between checks.

…it should be as short a time as possible, but the question is what is possible and still practical. If the checking period was half the industry recommended timescale, i.e. 6 hrs then I can see that starts to create issues for some small contractors and I still don't think I personally would be comfortable with knowing an animal I was responsible for was stuck fast in a glue trap for 5 ½ hrs given the stress and discomfort they would likely be under."

SASA suggested that inspection times could be covered under any proposed licensing scheme:

"…while more regular checks pose significant difficulties, they are not insurmountable. Current practices of training one or more site representatives to check traps could be a solution in some circumstances and within a licensing system it could be a condition of the licence that those persons are named and trained appropriately."

SASA also pointed to the use of remote trap alerts as a potential solution under licensing.

OneKind quoted comments seen on the Mumsnet platform, including:

• I had a bucket of water outside the back door to drown the mice in.
• I suffocated them by placing the trap and mouse in a plastic food bag and tying it up tight.

The British Columbia Society for the Prevention of Cruelty to Animals (BC SPCA) recommended adopting scientifically based criteria to measure humaneness, such as the criteria it has developed (using North American reference documents). To be considered scientifically humane according to these criteria, a lethal wildlife control method would cause:

1) Short duration to irreversible unconsciousness and/or death (approximately < 1 minute)

2) Short duration of physical injury and/or pain (approximately < 1 minute)

3) Low severity of physical injury and/or pain (physical injury approximately ≤ 10 points on ISO Trauma scale (Proulx 1999))

4) Short duration of distress

5) Low severity of distress

6) High reliability of method when used by trained and competent individuals

7) Minimal impact on non-target animals

8) Accessibility of animal for confirmation of irreversible unconsciousness or death.

Conclusion – animal welfare issues

The Commission noted unanimous recognition that glue traps cause animal suffering, with the majority of respondents indicating the likelihood that their use causes significant and potentially prolonged animal suffering to the target species. Importantly, concerns are not isolated to a particular aspect of the use of glue traps and even with optimal use (frequent checking and effective dispatch) there remains a significant animal welfare concern. It is the view of the Commission that there is no way that glue traps can be used without causing animal suffering.

Non-target captures

These were raised by several stakeholders including HSI UK who referred to "many instances" of birds being trapped, as well as small mammals, reptiles and pets.

Between 2015 and 2019, the Royal Society for the Prevention of Cruelty to Animals (RSPCA), which operates in England and Wales, received 243 reports of glue trap incidents of which over 73% involved pets and non-target wildlife (RSPCA, 2020).

The RSPCA stated on its website:

"The figures from the last five years show that we received 13 reports in which cats had become stuck to a glue trap and seven incidents involving exotic pet snakes, as well as other cases involving dogs, pigeons, owls, ferrets and even a parrot. Victims of these traps have suffered horrendous injuries, many of which have been fatal."

Conclusion – non-target captures

There is an undeniable risk of capture of non-target species. However, without knowing how frequently glue traps are used it is not possible to quantify that risk. Information on how 'indiscriminate' other forms of control are in comparison to glue traps would also be useful – in relation to rodenticides in particular.

Alternative methods

The BPCA listed a "risk hierarchy" of methods followed by its members, ranging from proofing of premises to exclude rats and mice, through traps and rodenticides, to glue boards, which are described as the last resort. While it did not provide scientific or statistical references, the BPCA said that there were circumstances where there was no alternative to the use of glue traps by professionals.

Conversely, Humane Wildlife Solutions, a Scottish-based company, stressed that it used only non-lethal methods such as repelling and deterring rodents.

The BC SPCA stated that, while last-resort use of glue traps by professionals in food handling facilities was currently permitted under its AnimalKind accreditation-and-referral programme, this approval was going to be removed. This, it said, was partly due to the emergence of alternatives such as captive bolt traps, snap traps wired to send text alerts when triggered, and, in some markets, ContraPest rodent birth control.

SASA advised that alternatives to be tried should include:

"… exclusion, i.e. if the rodents are coming in and out via a particular route(s) then these should be sealed off or made impassable. The other main alternatives are traps (live and/or kill) and rodenticides."

However, SASA noted that there were drawbacks:

"The first option may not be applicable and probably has to be combined with others anyway (to remove any rodents that are already inside), and the others may encounter issues such as neophobia or rodenticide resistance although these might be overcome by different trap types or lures, different rodenticide baits and/or different bait presentation. In some circumstance rodenticides may not be desirable as the animals could die out of sight and present other contamination risks as they decay and therefore might conceivably be discounted in some locations, and of course you might be dealing with a population with rodenticide resistance. Thus, any list of methods has to be flexible and allow for some to be deemed inappropriate or impractical in some situations."

SASA took the view that trying alternatives could build in delay in situations where it was imperative that rats be removed, and that this might be undesirable. It was not certain that there was good experimental evidence that glue traps were "better" at catching rodents than more conventional traps, and indeed at least one scientific paper suggested that the reverse was true for mouse trapping (Corrigan, 1998). However, SASA concluded:

"It might however be argued that depending on how critical the rodent removal is, that trying all possible methods at the same or within a short time frame might be a sensible approach."

OneKind recommended more research and development into the possibilities for using genuinely humane methods of deterrence, at large scale, by public bodies and businesses. The Commission is aware that research continues in these areas – for example, the Non-Chemical Alternatives for Rodent Control (NoCheRo) project on more environment-friendly alternatives to anticoagulant rodenticides.

In New Zealand, in tandem with legislation on glue traps (see below) a stakeholder group was set up to identify humane alternatives to glue board traps. A review of available methods for rodent detection and control was commissioned and published in 2015 (New Zealand Ministry of Primary Industries (2015)). This detailed report might form the basis for an up-to-date review if the Scottish Ministers decide to support restrictions on the use of glue boards. In the meantime, its summary of alternatives is useful:

Table 1. Methods used for rodent control

Rodent control method Potential replacement for glueboards

Fumigation Yes - limited applicability

Trapping: live traps Yes - commonly

Trapping: kill traps (breakback) Yes - commonly

Trapping: kill traps (electrocution) Yes - limited applicability

Trapping: kill traps (CO2) Yes – limited applicability

Poisoning: anticoagulants Yes - where applicable

Poisoning: other toxins Yes - where applicable

Non-toxic lethal compounds No - evidence of efficacy lacking

Repellents: chemical Yes - limited applicability

Repellents: ultrasonic, electromagnetic and ionic devices No - evidence of efficacy lacking

Biological control: diseases and parasites No

Biological control: fertility control No

The Commission is aware that further research into different rat management methods has been undertaken in early 2021 and will be published shortly. The Commission proposes to review the outcomes of that research when available and to consider whether these affect the recommendations made in this report.

The number of Ministerial approvals to sell/use glue traps declined from 24 in 2015 to 2 in 2020 (New Zealand Ministry for Primary Industries, 2020). This decline was accompanied by a concomitant reduction in the number of glue traps sold and used over the same period. In 2015, a total of 24,564 boards were sold under Ministerial approval compared with only 48 in 2019. NAWAC commented:

"The commercial pest management industry appears to have adapted well to the use of alternative methods."

Conclusion – alternative methods

There are a range of pest control methods available and glue traps are often cited as only being used as a last resort in high risk (to public health) settings. The Commission concludes that it is difficult to justify the use of glue traps, except possibly in the most significantly high-risk (to public health) settings, such as hospitals. However, even in those settings the Commission cannot support the continued use of glue traps, given the very high likelihood of animal suffering. We note no evidence is provided to back up the statement that glue traps are only used as a last resort and there is a likelihood that this is not always the case with some operators. Independent expert advice should be harnessed to identify a ranking of likely suffering caused by all current methods of pest control to justify a hierarchy or cascade of future use.

Ethical considerations

The BC SPCA referred to the capacity of target animals to suffer:

"While rodent control may justify use of lethal methods due to concerns related to human health and safety, commensal rodents have a similar capacity for suffering as other animals, and humaneness of control methods should also be considered."

Their submission and those of OneKind, UFAW and the Wild Animal Welfare Committee requested the Commission to consider the desirability of an ethical approach to pest control and in particular the International Consensus Principles for Humane Wildlife Control (Dubois et al, 2017).

OneKind said:

"If it is deemed necessary to kill or 'manage' wild animals, we recommend following the international consensus principles for ethical wildlife control (Dubois et al, 2017).

The final of these seven principles seems particularly relevant here:

'Decisions to control wildlife should be based on the specifics of the situation, not negative labels applied to the target species. When animals are labelled with terms such as 'introduced', 'abundant', and 'pest', broad approaches to control are sometimes advocated and little attention is paid to the specifics of the case. Wildlife control should not be undertaken just because a negatively labelled species is present.

…Animals assigned labels with negative connotations often receive less welfare consideration than valued species.

… Because vertebrate animals of similar cognitive and emotional complexity can be expected to have similar capacities for suffering, there is no reason consideration of animal welfare should depend on how a species has been categorized or the potential detrimental effects of the animal's presence or behaviour.' "

UFAW also discussed the ethics of all pest control:

"The first question which should be addressed when tackling problems caused by 'pest' species is to ask whether control is necessary or whether prevention and deterrence will suffice. If control is required, then UFAW advises (UFAW, 2008) that those controlling rodents or other vertebrate 'pests' should respect their welfare by adhering to the following principles: 1) affect no more animals than necessary to achieve the aim and 2) refine control methods so as to minimise unnecessary suffering (fear and pain). Decisions to undertake control measures against wildlife should be based on ethical principles and should follow a logical decision-making process which seeks to justify the decision to control the target species and then minimise the impacts of control (Dubois et al, 2017)."

OneKind also commented on the tendency to ascribe lower value to animals deemed as pests, despite their equal capacity to suffer:

"… it is entirely necessary to recognise the inherent bias in our systems, and each of us as individuals, against animals who have for centuries been deemed as 'pests' and thus afforded less consideration. Any situation where a kitten was stuck in a state of terror for twelve hours, struggling to the point of breaking bones, chewing of his/her own limbs, and then bludgeoned to death (if lucky), drowned, left to suffocate or allowed to die of injuries or dehydration would be considered absolutely unacceptable in our society. This is demonstrated by the horrified reaction when 'non-target' animals such as kittens occasionally do get stuck on glue traps."

Conclusion – ethical considerations

The labelling of target species as 'pests' in this context should be discouraged in the future. It is important to recognise that 'pest' animals have the potential to suffer to the same extent as other sentient 'non-pest' species. In considering all 'pest' control methods, the Commission would like to see these ethical considerations higher up the agenda and explicitly addressed in all future discussions.

Legislation in other countries

The Commission received information, either directly or in submissions from interest groups, regarding legislation in New Zealand, Ireland and the states of Tasmania and Victoria, Australia.

Ireland: Under section 42 of the Wildlife (Amendment) Act 2000 (Irish Parliament, 2000), the Minister for Environment, Heritage and Local Government has authority to approve and regulate certain traps by order. The Wildlife Act 1976 (Approved Traps, Snares and Nets) Regulations 2003 do not list glue traps as approved traps. It is an offence to import, possess, sell or offer for sale unauthorised traps: there is provision for glue trap use under ministerial authorisation (licence) but we are not aware that any licences have been issued. The National Parks and Wildlife Service has been active in enforcing this legislation, visiting retailers and informing them of the legal position. The ISPCA stated that it had not received any complaints in relation to glue traps and was not aware of any retailers stocking them contrary to the regulations. It remains possible to source glue traps online although we understand that possession would be a breach.

New Zealand: In 2000, the National Animal Welfare Advisory Committee (NAWAC) an independent statutory committee established under New Zealand's Animal Welfare Act 1999, recommended that the importation, sale and use of glue traps be prohibited in New Zealand. The Animal Welfare (Glueboard Traps) Order 2009 (New Zealand Ministry for Primary Industries, 2009) prohibits sale and use of glue boards for rodents from 1 January 2015, except under Ministerial approval. Ministerial approval to sell or use rodent glue board traps can be granted where it is in the public interest and there is no viable alternative.

The approvals for use are for limited circumstances for:

• biosecurity and conservation purposes
• use in and around food storage and processing facilities
• specialist applications where high hygiene is required.

A five-year period between the issue of the regulations and the prohibition coming into force was put in place to allow time for people and groups who routinely used glue boards as part of their business to investigate and develop more humane alternatives. NAWAC continues to monitor both the granting of Ministerial approvals and the reports that sellers and users are required to supply to the Ministry for Primary Industries.

Tasmania: Amendments in 2008 to the Animal Welfare Act of Tasmania prohibit the use of glue traps for animals, other than with Ministerial exemption. A blanket exemption for licensed commercial operators has been issued, so long as their use complies with the Australian Environmental Pest Managers' Association Guidelines for the Use of Rodent Glueboards in Australia by the Pest Management Industry. (Humane Pest Control, 2006).

Victoria: Glue traps were banned in 2008 from public use and only permitted by ministerial approval for purchase and use by commercial pest controllers in commercial food manufacturing premises. In December 2019 the State Government of Victoria adopted an outright ban on the sale, setting and use of all glue traps 'capable of trapping an animal', as part of its Prevention of Cruelty to Animals (POCTA) Regulations 2019 (State Government of Victoria (2019)) The government website emphasises:

"This prohibition includes use by commercial pest controllers for rodent management under any circumstances."

Conclusion – legislation in other countries

In those countries that have introduced legislation, the general direction is toward licensing the use of glue traps in specific and limited circumstances and the use of glue traps by the general public has been banned. Where a strict licensing approach has been adopted the number of applications for such licences has reduced significantly or has not occurred at all. The Commission concludes that an outright ban on the sale of glue traps to the general public is appropriate and that to further reduce (and ultimately end) their use, a very strict licensing approach should be adopted for industry users.