Humane Management of Rats, Mice and Moles Detailed Advice

Can I control rats, mice or moles myself?

It is important to think carefully about the whole process of managing wild animals before taking action, including what you will do if things do not go to plan. For example, are you confident about what you will do with a live caught rat or mole? Will you be able to humanely kill a rodent caught on a glue trap or unexpectedly still alive when caught in a lethal snap trap? Would you know what to do if a non-target animal is caught by a trap? If you are not sure then seek advice from a trained and qualified pest controller to manage the problem. Failure to treat an animal humanely once you have captured it may be a criminal offence.

Working with a pest controller If you have a rat or mouse problem that you do not wish to deal with yourself, contact the Environmental Health Department of your local authority or call in a professional pest control company. Anyone can call themselves a pest controller in the UK but good pest controllers will be well-trained and qualified to use the methods they employ ensuring that any requirement to control pests is carried out as humanely as possible. For example, they will be trained to Royal Society for Public Health Level 2 in Pest Management. See also the Confederation of European Pest Management Associations (CEPA) standard for a professional pest controller.  A good pest controller will provide advice and explanation of the various rodent control methods they use and also advise you on how to proof your property to avoid future problems. If you are concerned about minimising the welfare impact of the methods the pest controller will use, please discuss the methods to be used with them, explaining that you wish to use methods with the lowest welfare impacts, such as snap-traps or live traps and that you do not wish to use methods with high welfare impacts such as rodenticides or glue traps until all other approaches have been exhausted.

After reading our detailed information on moles you may feel you can manage or tolerate the presence of moles rather than needing to remove them. It can be very difficult for a non-professional to capture moles, so if you have moles that you feel need to be removed, find a professional mole catcher.

“Pests” or wild animals in conflict with humans?

Many people consider rats, mice and moles to be ‘pests’ or ‘vermin’, but using such labels can encourage people to disregard animal welfare. While we refer here to ‘pest controllers’, because this is the recognised terminology for the profession, in general we talk about managing rather controlling wildlife.

Before reading any further it may be worth having a look first at the seven principles of ethical management.

The seven principles of ethical wildlife management were agreed by an international panel of 20 diverse experts. The principles are interdependent and should be applied step-wise as shown here (Dubois et al., 2017).

Rats and mice

Brown Rat - Zeynel Cebeci, CC BY-SA 4.0  via Wikimedia Commons

Norway (brown) rats (Rattus norvegicus) and house mice (Mus musculus domesticus) are the rodent species most likely to be found indoors, while black rats (Rattus rattus) are present in some locations. Rats and mice are referred to as ‘commensal rodents’ (commensal meaning ‘shares our table’).

 

 

House Mouse CC2.0 David Illig via Flickr

 

 

 

 

Woodmice, also known as long-tailed field mice, (Apodemus sylvaticus) and, rarely, bank voles (Myodes glareolus) may sometimes enter homes and other buildings in rural areas. Rodents may be attracted into buildings by food sources that are accessible in kitchens, or by nesting opportunities, eg, in loft insulation. They may also target animal feed in chicken runs or poorly secured feed storage bins that are kept outside or in sheds, etc.  Food provided for garden birds is another common source of food which attracts rodents. Other species that may enter homes, but which are neither rats, nor mice, are grey squirrels (Sciurus carolinensis) and dormice (Glis glis); the methods described in this advice are not suitable for squirrels, while dormice are protected and cannot be captured or killed without a license (see note below in Appendix). It is important to know which species you have encountered before you consider any form of management, both to ensure you don’t break the law and to help you select the most appropriate management method, where this is necessary

Is it a rat or a mouse? Rats and mice are rodents and they have a similar overall body plan. However, rats are significantly bigger than mice (adult Norway rats, Rattus norvegicus, head-body length 21-29cm, tail length 17-23cm and weight usually 275-520g; adult house mice, Mus musculus domesticus, head-body length 7-10cm, tail length 7-10cm and weight 12-22g (Macdonald and Barrett, 1993)). It is easy to confuse an adult house mouse with a baby rat, but Norway rats have relatively small ears and their tail is shorter than their head and body put together – their tail is also relatively thick and hairless (Rentokil, Current in 2022); Norway rats are usually brown (and sometimes known as brown rats) but may be black, with paler grey below. In contrast, house mice have relatively larger ears, a smaller, sharper snout and a longer, thinner tail covered in hair; house mice are generally a uniform greyish-brown, slightly lighter below. Wood mice, also known as long-tailed field mice (Apodemus sylvaticus) have larger eyes and ears, a whiter belly and a longer tail, than house mice (Macdonald and Barrett, 1993). Norway rats and house mice tend to prefer cereals. Rats tend to ‘cut’ grain when eating, leaving pieces that appear to have been chopped, while house mice tend to remove the outer husk of grain to eat the contents. Norway rat droppings are 10-20mm long, dark brown and form a tapered spindle shape, like a large grain of rice. House mouse droppings are 3-8mm long, black and granular in shape and often found in clusters (Rentokil, Current in 2022). Black rats (also known as ship rats or roof rats, Rattus rattus) are rare in the UK; compared to Norway rats they are smaller (head-body length 15-24cm, tail length 11-26cm and weight 145-280g), darker in colour (varies from black to brown) (Macdonald and Barrett, 1993), have a slimmer body, large thin ears, a pointed nose and a tail longer than their head and body. They prefer moist fruit and their droppings are long, thin, smaller than Norway rat droppings and curved with pointed ends (Rentokil, Current in 2022)

 

 

 

Dormouse (Glis glis)

 

 

 

 

 

Grey Squirrel

 

 

 

Rat and mouse carcases and unused rodenticides must be disposed of carefully  and according to the law.

Preventing rat or mouse problems

Proofing of buildings and vulnerable resources, and good food hygiene, will reduce the chance of problems arising.

Rats and mice need food, water, cover and nesting sites to survive. You can minimise the risk of rat or mouse problems by preventing them from entering buildings or accessing the resources they need (Natural England 2012a, 2012b). Ideally, this should be done proactively, rather than waiting for a problem to occur. However, if rats or mice are already present, and causing intolerable problems, they will need to be removed (see ‘Managing rat or mouse problems’ below) before proofing work can take place. Rats and mice are agile and adaptable animals, capable of squeezing through extremely small spaces (rats, 19mm; mice, 6mm, the size of the end of a biro); they burrow, climb and swim, and can even gnaw some metals so proofing needs to be thorough to properly exclude them. You can do this yourself (a good pest controller should be able to offer some advice on how to do this) or engage a professional proofing company to do it. Rodent-proofing and good food hygiene measures should be maintained year-round.  Recommended preventative actions are described below.

 

Preventative action Proofing and good food hygiene should be conducted proactively to minimise the risk of rats or mice entering houses and other buildings, or accessing vulnerable resources. If rats or mice are already present, then they will need to be removed before taking action to prevent them from returning. Professional proofing companies exist if you do not want or feel able to do this work yourself. Signs of rat or mouse infestation include: ·       Live / dead sightings ·       Noise ·       Smell ·       Hairs / Footprints / tail swipes ·       Droppings / Urine stains ·       Urine pillars ·       Gnawing & damage ·       Damaged foodstuffs ·       Runs ·       Smear marks Proofing materials should be robust. Rodent teeth are able to penetrate lead, mild steel, concrete, copper, wood, plastic, electrical wires and even crumbling concrete. Proofing may be overcome if rodent activity is high enough, so control or other preventative methods may also be required. Recommended proofing and food hygiene actions include the following (Backyard chicken project, 2021; Natural England, 2012a, b, c): ·       First identify points where rats or mice are likely to be entering buildings or animal housing, or accessing resources - look for holes, runs, droppings, damage, footprints or other signs. ·       Holes of 6mm may allow entry by mice. Block holes and gaps in walls, floors, doors, roofs, fascia, attic vents and partitions. Block gaps around service entry points (e.g., gas and water pipes and electricity cables). Holes of ≤10cm or so may be blocked using wire wool or netting and covered with welded wire mesh (not chicken wire); larger holes need to be repaired to original condition. Check the integrity of cladding, brickwork and mortar. Install animal-proof chimney caps on open chimneys. ·       Check doors fit tightly and thresholds are intact. Attach bristle strips to the bottom of doors. ·       Proof drainage pipes and gullies using grilles, flaps, crushed wire mesh etc. ·       Replace damaged drain covers. ·       Add baffles/metal collars to rainwater drainpipes and cables to stop rats from scaling them. ·       Ensure air bricks are in place and intact. ·       Incorporate proofing into buildings when building from scratch, to make it harder for rats to burrow. ·       If building a chicken coop, position it > 30cm off the ground or make a poured concrete floor. If an existing coop floor is made of wood or earth, line it with welded wire mesh, folding it at the corners and stapling it to the walls a few centimetres up. Build the walls, floor and roof of chicken runs with welded wire mesh. -     Collect eggs from chicken coops regularly. ·     Remove harbourage, such as vegetation, rubbish and piles of materials from around building access points. Regularly fill rat holes in the earth around the area of concern. ·      Remove spilled food and do not leave pet or other animal food available; store food in rodent-proof containers with secure lids. -      Remove, or make inaccessible, water sources where possible. -      If composting food waste, use a lidded and rodent-proof metal compost bin. If you suspect that bats or birds are using your building, then it is against the law to disturb their places of rest [Bats - the Wildlife and Countryside Act 1981 (as amended) and Conservation of Habitats and Species Regulations (2017) (as amended); Birds - the Wildlife and Countryside Act 1981 (as amended)].  This includes breeding, nesting or roosting sites. If proofing work is likely to disturb either bats or birds, then professional advice should be sought, such as from Natural England and the Bat Conservation Trust (Bat Conservation Trust, Current in 2022a, b; Natural England, 2015a, b).”

Managing rat or mouse problems

Even if you care deeply about animal welfare you may have to use lethal control methods to remove rats or mice in some circumstances. Rats and mice can pose a serious public health hazard. But there is a lot you can do to reduce the welfare impacts of rat and mouse control even when using lethal methods. In 2022 a research study, part-funded by UFAW (Baker at al. 2022) compared the commonly used methods to control rats in the UK and rated their welfare impacts. This study showed that the impacts of some methods were much more severe than others. This study forms the basis of the advice we give concerning the control of rats, and many of its findings are also likely to be applicable to mice. Before commencing any form of rodent control it is crucial that you confirm whether you have rats or mice (or another species) present, because many control methods are species-specific and some methods are only legally permitted for one species. Also, using a method intended for a different species may cause unintended welfare impacts, for example, trapping a rat in a snap trap designed for mice is likely to injure it rather than killing it quickly. If you are not sure which species you have, then you should employ a trained and qualified pest controller.

Snap trapping

A high quality snap trap. Image:  Baker.

A good quality snap trap is likely to be the most humane way to kill a rat or mouse.

A snap trap (or ‘break-back’ trap) is a lethal spring trap with a flat treadle or bait pan that releases a metal loop or plastic jaws, which close down on the target animal (Chartered Institute of Environmental Health 2014). Snap traps are intended to strike rats or mice on the head, neck or spinal column or to constrict the thorax. They are designed either for rats, or for mice, and the correct size of trap should always be used for the species concerned[. Snap traps are unregulated in the UK, and virtually everywhere else^[1], meaning they are not required to meet particular welfare standards. This means it is very difficult for consumers to buy the best traps, which are most likely to kill rats or mice with the minimum suffering. A good snap trap will cause fatal damage to rats or mice by striking and fracturing the upper neck or back of the skull, causing immediate or very rapid unconsciousness, followed by death (Parrott et al. 2009). Poor quality traps that strike rodents elsewhere, or that are weaker, are likely to produce a worse welfare outcome.

Research has shown that mechanical performance varies widely among rat snap traps, and among mouse snap traps, indicating that welfare performance is also likely to vary and that some traps may not cause unconsciousness rapidly (Baker et al. 2012). Rodents, caught in snap traps, and which are not rapidly killed are likely to suffer significantly before they die. However, the NoCheRo Working Group have developed guidance for identifying high welfare snap traps (Schlötelburg et al. 2021) and several rat and mouse traps have been shown to meet these standards - a list of these traps is shown below.

 

High quality snap traps have a wide opening angle and a double-peg type spring.

High welfare snap traps Snap traps (or ‘break-back’ traps) are unregulated in the UK and almost everywhere else (Schlötelburg et al., 2021), although there are concerns about their welfare performance (Baker et al., 2012) and there have been calls for a voluntary snap trap certification scheme (Baker, 2017). The NoCheRo Working Group (a European enterprise) set out to devise exacting welfare and efficacy standards for snap traps, with the goal of establishing a voluntary certification scheme for such traps. Their main motivation was to position traps as a viable and humane alternative to anticoagulant rodenticides, which have immense impacts lasting days on the welfare of poisoned rats and mice, as well as posing high risks of accidental poisoning to non-target species. In 2021, the group published detailed guidance on testing snap traps for use in a certification scheme; the standards required for traps to cause irreversible unconsciousness in 12 tests are shown below (Schlötelburg et al., 2021).     The European Commission is reviewing this guidance and a decision will be made in 2022 about establishing a voluntary trap certification scheme based on this. In the meantime, several types of rat and mouse trap have been tested by the German Environment Agency and shown to meet at least the Category B welfare standard – these can be recommended and are listed below. Providing the scheme goes ahead, this list will be updated to show which traps meet Category A and which meet Category B. Traps for Norway rats ·       Anticimex Smart Catch B-0308-00-00 Anticimex GmbH & Co. KG ·       Anticimex Smart Catch Mini B-0323-00-00 Anticimex Innovation         Center A/S   Traps for house mice ·       Gorilla Trap Maus + Snapbox, Futura GmbH ·       Anticimex Smart Catch, Anticimex GmbH & Co. KG ·       Anticimex Smart Box, Anticimex GmbH & Co. KG ·       SuperCat Mausefalle Pro, Swissinno Solutions AG ·       NoSeeNoTouch Mausefalle, Swissinno Solutions AG ·       Anticimex Smart Snap, Anticimex Innovation Center A/S

 

A snap trap with: (a) a double-peg spring; and (b) a wide opening angle (source: Sandra Baker ).

We recommend using the traps listed above, if possible, but, if they cannot be sourced, then it is advisable to choose one with a double peg-type spring (see below) and a wide opening angle (90-1800) (see further below) , as research has shown that these features tend to produce a more powerful trap, which may be more likely to kill rodents quickly (Baker et al 2012).

Traps should be well maintained, positioned and set, to increase the lTraps with a jaw-type spring and a small opening angle (<900) (see below) tend to be weaker and may injure rodents or kill them more slowly (Baker et al. 2012).likelihood of causing rapid unconsciousness and a clean kill. Gloves should be worn to avoid contaminating traps with human scent and traps may be baited with biscuit, oats, chocolate or peanut butter. Traps should be placed on runs used by rats or mice, so that they are perpendicular to a wall with the capture end against the wall; alternatively, if you know the direction of rodent travel, they can be placed parallel to the wall with a large box immediately to the side, to direct rodents into the trap.

There is always a risk that a trap will strike a rat or mouse on an extremity, such as a tail or paw, or other sub-optimal body location; or a weak trap might fail to cause rapid unconsciousness, even if that animal is caught in the correct position. In either case, the trapped rodent may take considerably longer to die, experiencing pain, fear and anxiety (Baker et al. 2022). Therefore, once traps are set, they should be checked as often as possible and at least twice daily. Rats or mice found trapped, but still alive, must be humanely killed as quickly as possible and preparations must be made in advance for this possibility. Carcases should be disposed of carefully and hygienically.

Humane methods for killing live-captured rats and mice Where you will need to humanely kill rats or mice, eg after capture on a glue trap or other live trap, you should prepare in advance to do this. If you are going to set snap traps or use rodenticides, you will also need to be prepared to quickly and humanely kill a rat or mouse that is still alive in a snap trap, or a rodent that has been poisoned but is not yet dead. The Wild Mammals Protection Act 1996 requires that in the context of pest control, animals should be killed in a “reasonably swift and humane manner”. As outlined in the text, many people may find that humane killing is not an easy procedure. The following methods are considered to be humane: ·       Destruction of the brain by a strong and accurate blow to the head with a suitable implement (this is called a ‘concussive blow to the head’) ·       Lethal overdose of appropriate gaseous or injectable anaesthetic (this technology is not available for general use) ·       Destruction of the brain by shooting The latter two methods are unlikely to be available or applicable in most cases. Anaesthesia would most likely be impractical due to health and safety, and environmental, requirements, while drugs will be available by prescription only, severely limiting their use. Large infestations of rats are sometimes shot in England and Wales using air guns but a license would be needed in Scotland. Airguns are also sometimes used to dispatch live-trapped small rodents (BPCA, 2020), but in general, shooting is unlikely to be practical for commensal rodent control for safety reasons. The efficacy and humaneness of using a concussive blow to the head, depends on a strong and accurate blow with a suitable implement, such as to destroy the brain. In the case of a mouse caught on a glue board, some achieve this by turning the board over and powerfully and instantly, crushing the mouse beneath it. Removing live animals, especially rats, from live traps and restraining them to deliver such a blow is very difficult and potentially dangerous – it is important to avoid bites. Some operators advocate allowing the rat to run into a sack, held over the end of the trap before it is opened, and then gripping the animal through the sack, to hold it still, to deliver a heavy blow to the head. If the blow is delivered with sufficient force and accuracy this is a humane and reliable method, but the humaneness is obviously dependent on these two factors - force and accuracy. The method requires skill and a firm resolve. Not everyone is suited temperamentally to these procedures for killing live-caught rodents. Unless you are confident about your ability to do this well, then do not set glue traps or other live capture traps.   Drowning Some have argued that drowning may have advantages for the householder - it is easy to undertake (requiring no extra restraint of the trapped animal, nor removal from the trap) and requires no specialist equipment. It is effective, providing the animal is submerged for long-enough (a few minutes). The time to death of rats in fresh water was found to average 2.6 minutes (Yamamoto et al., 1983). However, drowning is likely to cause severely unpleasant feelings of fear and pain or extreme discomfort associated with ‘air hunger’ - wanting (and being unable) to breathe (Beausoleil and Mellor, 2015) - and with water entering the respiratory tract. Drowning therefore should not be used as a control method as it is inhumane and can also lead to prosecution (BASC and Natural Resources Wales, 2016). For example, people have been successfully prosecuted under the Animal Welfare Act (2006) for causing unnecessary suffering to live-trapped grey squirrels by drowning them (Ellicot, 2010; Williets, 2021). After killing, regardless of the method used, it is very important to confirm death. The important sign to check is: ·       No breathing or other movement. Where experience allows, other signs that operators may wish to check for are: ·       No blink reflex if the surface of the eye is gently touched with a soft implement (eg a feather, straw, cotton-bud stick) ·       No reaction to a sharp pinch of the soft tissue of a paw ·       No heart beat If there is any suspicion that an animal might still be alive, the killing procedure should be repeated immediately taking care to ensure it is effective.

Non-target animals (including pets) are at risk of injury or death if accidentally caught in snap traps. Children are also at risk of injury. If traps are set outdoors, each trap should be placed inside a secure, tamper-resistant box, designed for the purpose, or under suitable existing cover to minimise access by non-target animals. Indoors, children and pets should be kept away from areas where traps are set, or each trap should be placed in a secure, tamper-resistant box. Injured non-target animals found trapped, but still alive, should be humanely killed as quickly as possible.

A closed, tamper-resistant box with trap visible inside.

Advantages:

• Good quality traps can produce a very rapid death. Note, trap quality can diminish with use or age, especially wooden traps.
• Traps used properly present minimal risk to people and non-target animals.
• Snap traps are non-toxic, so they are suitable for use in some food processing places

Disadvantages:

• Animals trapped in poor quality traps may experience pain, fear and anxiety before becoming unconscious
• Target animals may be injured in traps if poor quality traps are used or if traps are poorly positioned or set. Sometimes animals may be injured even when all correct procedures are followed.
• Non-target animals (including pets) may be killed or injured and children may be injured if traps are not suitably protected.
• Snap trapping may not be sufficiently efficient in some situations, e.g., large infestations or infestations in critical infrastructure.

N.B. We do not recommend using a ‘sealed’ mouse trap for killing mice – these are traps inside sealed boxes that cannot be opened; they are promoted on the grounds that they are hygienic and that users will not need to see or deal with a dead mouse in the trap. They are designed to be thrown away with the mouse inside but there are reports about live and potentially injured mice being trapped inside with no way of releasing or humanely killing them (Baker and Sharp 2015).

Alphachoralose rodenticide poisoning

Alphachloralose can only legally be used against mice, indoors and where the temperature is below 150C). To our knowledge, the welfare impacts of alphachloralose on mice have not been assessed.

Alphachloralose was once used as a sedative and general anaesthetic in human and animal medicine, but is now used as a rodenticide against mice. It has only very limited use as a rodenticide. First, alphachloralose products are not very palatable. Second, it can only be used in very limited circumstances (temperatures, locations and only for mice). It differs from other rodenticide poisons (e.g., anticoagulants and cholecalciferol), in that it acts centrally, reducing brain activity, slowing the heart, respiration and metabolism, and lowering body temperature by up to 20 ⁰C in mice, resulting in death through hypothermia (Mason and Littin 2003). Because alphachloralose kills via hypothermia, it should only be used at temperatures below 15 0C (Meehan 1984); in warmer climates, death may be prolonged or render alphachloralose ineffective. Use at greater temperatures may result in poisoned mice recovering. Alphachloralose is not suitable or legally permitted for use in the UK against rats; this is because their larger size means that they retain body warmth better and are less likely to become hypothermic, meaning this method will be less humane for rats than for mice. In the UK, alphachloralose can only be used indoors, because of perceived risks of accidental or secondary poisoning[2]. Because it can only be used indoors, and where temperatures are less than 15 ⁰C, it is generally not suitable for use in domestic dwellings and is likely to have only limited utility. 

Alphachloralose likely causes mice physical discomfort for a period of minutes before they become unconscious and die of respiratory failure and hypothermia. Mice are effectively anaesthetised, but before unconsciousness occurs, mice show signs of inebriation, hyperactivity and uncoordinated movement. They may also experience weakness, muscle twitching, increased salivation and increased sensitivity to touch or sound. Animals become sleepy and may have reduced sensitivity to pain before becoming unconscious. The symptomatic period may be as little as 10-15 minutes and mice can be unconscious within 15 minutes of feeding on alphachloralose bait (Meehan 1984). While humans poisoned with alphachloralose report no pain, at higher doses they may experience coughing and shortness of breath, headaches, nausea, vomiting and dizziness. The UK’s Pesticide Safety Directorate described this method of mouse management as ‘relatively humane’  (Pestcide Safety Directorate) 1997).

Accidental poisoning of non-target species with alphachloralose is simple to reverse, particularly in small animals, which largely just need to be kept warm. Poisoning of rats, rather than target mice, could involve rats experiencing seizures while conscious. Because the poison acts so quickly, mice are likely to die above ground, where they are accessible to predators or scavengers, but risks of secondary poisoning can be minimised by collecting and properly disposing of poisoned carcases. Secondary poisoning has killed buzzards and red kites, but risks are low for larger predators because alphachloralose does not accumulate in their bodies and heat loss is likely to be insufficient to cause death (Mason and Littin 2003).

Advantages

• More humane than other baiting methods
• Less toxic to humans than other rodenticides
• Treatment for accidental poisoning is relatively simple (keep animal warm)

Disadvantages

• Cannot be used for rats
• Can only be used indoors and at temperatures below 15 0C

Live trapping

Live trapping followed by humane killing is likely to be less humane than using good quality snap traps [or alphachloralose for mice, where appropriate] but more humane than glue traps or anticoagulant or cholecalciferol rodenticides.

CC BY-SA 4.0, Snowmanradio,  via Wikimedia Commons

Live trapping involves capturing a rat or mouse alive in a cage or box trap. This may seem like an attractive option to those who wish to avoid killing, but using live traps requires careful thought. Holding a live wild animal in a trap is likely to cause considerable suffering and, if you live trap a rat or mouse, you will then need to either: 1) release it in a non-familiar area, sufficiently far away that it cannot find its way back; or 2) humanely kill it.

Many ecologists suggest rats or mice released outside their territory are unlikely to survive, therefore live trapping and releasing elsewhere is likely to be less humane than using a good quality lethal snap trap, and is not recommended. Killing live rodents humanely is beyond the experience (or competence) of many people, and may pose a risk to those not skilled in this technique. If you are planning to kill live trapped rodents, you will need to make preparations for this in advance. Alternatively, seek advice from a trained and qualified pest controller from the outset. The Animal Welfare Act (2006) puts in place a duty of care for the welfare of all vertebrates under human control, so anyone holding a live wild rodent in a trap, in captivity or transporting it for release, could commit an offence under the Act if they were deemed to cause it any unnecessary suffering 

Law relating to the capture and release of rats, mice and moles The legal framework relating to the release of captured small mammals includes both: (i) animal welfare; and (ii) species conservation elements. The latter addresses the potential risks to UK wildlife and biodiversity of releasing species that are not considered to be ‘ordinarily resident’ in the UK. The text below is just a summary so please refer to the legislation for the precise wording. (i) The welfare of captured wild vertebrates is covered by the Animal Welfare Act 2006 (https://www.legislation.gov.uk/ukpga/2006/45/notes/contents), which puts in place a duty of care for the welfare of all vertebrates under human control. For example, anyone conducting wildlife management, who holds a rat, mouse or mole in a trap or enclosure, or in the hand, or during transportation, will be considered ‘responsible’ for that animal. The responsible person may commit an offence under the Act by causing suffering, which is deemed to be unnecessary, to an animal under their control - or by allowing someone else to do so (Natural England, 2010). Whether the suffering is unnecessary requires consideration of a number of factors, such as whether the suffering could reasonably have been avoided or reduced, whether the control operation was for a legitimate purpose and whether the suffering was proportionate to the purpose of the control operation concerned. The implications of this for releasing or killing captured animals is unclear, but the capture, release or killing of animals in circumstances that compromised or might compromise their welfare may be open to challenge, if the animal’s needs are not met as far as is reasonable in the circumstances. Leaving an animal in a live trap without food, water or shelter, might be an offence if the animal was left untended for longer than guidelines allow. A person releasing an animal may commit an offence if they do not take reasonable steps to ensure that, upon release, the animal is capable of fending for itself and living independently (Natural England, 2010). Where suffering inevitably occurs in the course of wildlife management, Natural England advise that an offence is unlikely to be committed, provided the appropriate regulations, guidance or codes of conduct are followed. The Animal Welfare Act does not apply to the humane destruction of an animal (Natural England, 2010). (ii) Section 14 of the Wildlife and Countryside Act 1981 (WCA) (https://www.legislation.gov.uk/ukpga/1981/69/section/14) prohibits the release into the wild any animal which is: 1) of a kind that is not ordinarily resident in and is not a regular visitor to Great Britain in a wild state; or 2) is included in Part 1 of Schedule 9 (https://www.legislation.gov.uk/ukpga/1981/69/schedule/9). At the time of writing (January 2022), the black rat (Rattus rattus), the fat/edible dormouse (Glis glis) and the grey squirrel (Sciurus carolinensis) are listed on Part 1 of Schedule 9 and therefore cannot be released, except under licence, and should be humanely killed. However, if a red squirrel (Sciurus vulgaris) is captured it must be released (BASC and Natural Resources Wales, 2016). Under the WCA there is no prohibition on the release of other species of rats or mice which are ordinarily resident in Great Britain. For example, the view of the Department for the Environment, Food and Rural Affairs (Defra) is that the release of Norway rats (Rattus norvegicus) into the wild is not unlawful under the Wildlife and Countryside Act 1981 because, despite their non-native origins, they could be classed as 'ordinarily resident' in Great Britain as they are now well-established. However, this does not necessarily mean that it is acceptable or permissible to release them on other people’s property. Bearing in mind the exceptions above, although the law does not prevent the release of captured norway rats, mice or moles), it is often likely to be unwise either because it is counterproductive to control and/or because it may have adverse welfare consequences for the animal (see above on the Animal Welfare Act 2006) and below for moles.

Rats and mice held in live traps may experience moderate to severe welfare impacts for hours while held in the trap. They will be subject to behavioural and movement restrictions, unable to forage, move or escape the attention of predators, and lactating females will be prevented from caring for young pups. For this reason it is critical that traps are checked regularly, if they are not, then animals may suffer or even starve whilst held in the trap.

Rodents may also injure themselves trying to escape. Trapped rats are likely to experience fear and distress as a result (Baker et al. 2022). Providing water and bedding in traps should decrease dehydration and chilling, while using covered rather than mesh traps might reduce deaths in live traps (Dizney, Jones, and Ruedas 2008). Once live traps are set, they should be checked as often as possible and at least every 12 hours to minimise welfare impacts. Remote monitoring devices can be used to immediately alert users to captures, but routine checks should be conducted anyway, in case of device malfunction. Once found, trapped animals should be dealt with quickly and humanely. Releasing rats near the point of capture is unlikely to solve the problem as the animals are likely to return unless the premises have been effectively proofed. Release of an animal elsewhere is not necessarily humane either. While the impacts of releasing rats have not been formally assessed, it is likely that they will suffer. Translocated animals may have difficulty finding food, water and shelter, and fail to integrate into new territory, and may suffer and die as a result (Mason and Littin 2003). Also if the area contains suitable habitat it is likely that other members of their species will be present, and the habitat may not support additional animals. This is likely to lead to conflict. Humane killing is much less likely to carry a risk of causing suffering than release in an unfamiliar area, and release of some species (such as black rats) may be illegal. It is therefore recommended that live caught rats and mice are humanely killed, using a concussive blow to the head. The trapped rat will need to be transferred to a sack before delivering the concussive blow to its head. If this process is conducted swiftly and competently, the whole process is likely to cause a moderate welfare impact for a few minutes, while the blow itself should cause concussion instantly (Baker et al. 2022). As noted above, the welfare of trapped rodents is covered by the Animal Welfare Act 2006, but provided the animal is killed in an appropriate and humane manner then, under Section 4(4) of this Act, the suffering will not be considered to be unnecessary. . Carcases should be disposed of carefully and hygienically.

There is a possibility of catching non-target animals in live-catch rodent traps. Provided these are unharmed and it is not illegal to do so, they can be safely released. If they are injured however, they will need to be humanely killed and you will need to make preparations for this in advance.

N.B. This advice does not relate to multi-catch mouse live traps. The welfare impact of such traps has not been determined and so at this time we would not recommend their use.

Advantages:

•     Captured non-target animals can be released if unharmed and providing this is legal.

•     Live traps are non-toxic and so suitable for use in some food processing premises

Disadvantages:

•     Live trapped animals may experience hours of fear and distress while held in the trap.

•     Animals released from live traps will return if released nearby and may suffer and not survive if they are released further away.

•     Using a humane killing method may be beyond many people’s abilities.

 

Glue trapping

Glue trapping is one of the least humane methods of rodent control which causes unacceptable suffering to most animals captured by them. UFAW believes the suffering caused by these devices means they should no longer be used. Under no circumstances should members of the public use glue traps.

A dead rat on a glue trap. These are supposed to be live-capture devices

Some pest-controllers argue that they must be allowed to use glue traps as a last resort where there is a serious threat to public health and safety which cannot be resolved rapidly by more humane methods. Despite this, some countries have successfully banned or severely restricted the use of glue traps, including India, Ireland and New Zealand. Restrictions are currently being considered in England, Scotland, and Wales.

Glue traps are pieces of wood, plastic or stiff card, covered with a strong viscous glue. When rats or mice run over a glue trap, they become stuck to the glue by the feet or fur. Animals should then be humanely killed by the user. However, many animals die on glue traps. If used, they should be checked regularly (the Pest Management Alliance recommend at least once every 12 hours (Pest Management Alliance 2017), but more frequent checks are strongly recommended). Any trapped rats or mice should be humanely killed. Failure to do this could constitute an offence under the Animal Welfare Act 2006. Only glue traps intended for use with rats must be used with rats, as they may be able to drag attached mouse glue traps away, making it difficult to find and kill the rats humanely. If glue traps are used, users should keep a record of how many are set, and where, and should ensure all boards are removed and safely disposed of at the end of treatment.

Glue traps can cause extreme suffering to trapped rodents for hours before trapped animals either die or are found and killed. Glue traps are one of the least humane methods of rodent control as a result and they should only ever be used as a genuine last resort and if they can be checked very frequently (Baker et al. 2022). Trapped rodents become more firmly stuck in the glue the more they struggle to escape, potentially tearing skin, breaking bones or chewing through their own limbs; their eyes and mouths may become glued shut. Rats and mice become exhausted from struggling and may die of exhaustion or from suffocating in glue (Frantz and Padula 1983). Trapped animals are unable to perform normal behaviours, such as foraging, moving, caring for pups or escaping from predators or from cannibalism by other trapped rodents, and they may self-mutilate if trapped for long periods. They are likely to experience anxiety, fear, panic and pain (Baker et al. 2022) and the Pest Management Alliance acknowledge that glue traps cause “acute physical suffering, fear and stress to trapped animals” (Pest Management Alliance 2017). Because of their extensive impacts on rodent and non-target animal welfare, glue traps are banned in New Zealand, the Republic of Ireland and India, and their use is restricted in Australia. Use of glue traps by members of the public is in the process of being banned in England[  and the Scottish Government’s Animal Welfare Commission has also proposed that use be restricted to use by professional pest controllers. Even in the hands of professionals, further restrictions are likely to be imposed on when and how glue traps can be used (Defra 2021), something UFAW strongly supports. Glue trapped rodents must be humanely killed, and we recommend using a concussive blow to the head of the animal. If conducted well, this is likely to cause a mild to moderate welfare impact for between seconds and a few minutes (Baker et al. 2022). As noted above, the welfare of trapped rodents is covered by the Animal Welfare Act 2006, but provided the animal is killed in an appropriate and humane manner then, under Section 4(4) of this Act, the suffering will not be considered to be unnecessary. However, killing live rodents humanely is beyond the experience (or competence) of many people. If you are planning to kill live trapped rodents, you will need to prepare for this in advance. Alternatively, engage a trained and qualified pest controller.

Non-target animals are at risk of becoming stuck to glue traps, including pets and wild animals such as bats, birds, small mammals and other species that may enter a house. While it may be possible to remove glue from larger animals, by massaging affected areas with a suitable (warmed) food grade oil, small animals are unlikely to survive and should be humanely killed and you will need to prepare for this possibility in advance. Glue traps should only be used indoors, and positioned to avoid risks to children, pets and non-target wildlife. Carcases should be disposed of carefully and hygienically, while still attached to traps, to avoid the trap becoming a non-target risk for animals that might try to remove the dead rat from the trap.

Advantages

• Glue traps are non-toxic so they are suitable for use in in some food processing facilities
• Pest controllers argue that glue traps are the only option to rapidly deal with an infestation in critical infrastructure where public safety or health is at serious risk.

Disadvantages

• Rodents experience hours of pain, fear, anxiety and panic
• In most cases, captured non-target animals cannot realistically be rescued
   

Anticoagulant rodenticide poisoning

Anticoagulants are one of the least humane methods of rodent control and should only be used as a last resort.

Most poisons available for use with rats and mice (rodenticides) are anticoagulant rodenticides (ARs). These poisons interfere with the target rodent’s metabolism of Vitamin K and disrupt its blood clotting mechanisms, ultimately causing death by blood loss through internal haemorrhaging and external bleeding (Mason and Littin 2003). Rats and mice in many areas are resistant to first generation anticoagulants (FGARs) and, where this is the case, FGARs should not be used. More potent second generation anticoagulants (SGARs) have been developed, but resistance to SGARs has also started to occur and SGARs are more persistent in the environment and more harmful to non-target species (CRRU UK 2021). Long-term rodenticide baiting should therefore not be routine practice and some ARs can only be used inside buildings. Poisoned bait must be properly protected from children and, as far as possible, from non-target animals. Outdoors, bait should be placed inside a secure, tamper-resistant bait box unless it can be placed under suitable existing cover. Where bait is used indoors, access by children and any non-target animals must also be restricted. If in doubt, use a bait box.

Anticoagulant poisoned rodents are likely to experience severe to extreme welfare impacts for days before dying and are thought to remain conscious throughout. Anticoagulants are one of the least humane methods of rodent control and should therefore only be used as a last resort. Haemorrhaging occurs into organs and body cavities, including the lungs, as well as in the skull, which is very painful in humans. Bleeding into the brain may cause convulsions or paralysis. Behaviour is compromised, making poisoned animals more vulnerable to predation. Animals will experience severe pain, breathlessness, weakness, thirst, dizziness, anxiety and fear (Baker et al. 2022). AR poisoned rodents die from anaemia or because blood loss causes organ failure. The UK’s Pesticide Safety Directorate described this method as ‘markedly inhumane’ as a result ( (Pesticides Safety Directorate) 1997). During treatment with rodenticides, rats and mice may sometimes be found poisoned but still alive. Such target animals should be humanely killed immediately and their carcases disposed of safely.

Anticoagulants pose a risk of primary poisoning to non-target animals through access to poison baits or secondary non-target poisoning² of predatory or scavenging species (eg, cats, dogs  badgers and birds) through access to poisoned rodent carcases or to the poisoned carcases of non-target bait feeders, such as wood mice or voles. Some SGARs (brodifacoum and flocoumafen) are so potent that the risk of secondary poisoning, through feeding on rodents killed using them, is so great that they are only allowed to be used indoors (Defra 2011). Accumulated ARs have been found in the stomachs and livers of many wild carnivore species and fatal secondary AR poisoning has been implicated in the deaths of members of several wild bird and mammal species as well as domestic cats and dogs. If you suspect that a pet or other non-target animal has been poisoned, call a vet straight away and if possible provide the toxin’s name, strength and the amount the animal has been exposed to, as well as the animal’s weight if that is known.

N.B., where wood mice (Apodemus sylvaticus) are present, it is illegal to use second generation anticoagulants as these do not have the necessary approvals for this species; if there is any doubt, speak to a trained and qualified pest controller.

Advantages

• Anticoagulants work slowly, allowing use of an anti-dote where accidental poisoning occurs
• Second generation anticoagulants are considered efficient and practical

Disadvantages

• Rodents experience days of pain, breathlessness, fear and anxiety
• Anticoagulants present a risk of primary and secondary non-target poisoning[³]
• ·Anticoagulant use may lead to anticoagulant resistance

Law relating to the use of rodenticides

It is vital that users of rodenticides follow strictly the pack instructions on how the product may be used and against which species - and that they are aware of the species that may be present . For example, it would be illegal to use a second generation anticoagulant rodenticide for the control of house mice (Mus musculus domesticus) where wood mice (Apodemus sylvaticus) are present because these products have not passed efficacy testing for this species. Rodenticides should be used within the CRRU (Campaign for Responsible Rodenticide Use, CRRU 2021) code of best practice (CRRU 2021). From Jan 2022 all rodenticide labels in the UK have been updated requiring the bait station / container to meet a certain standard of tamper resistance. Rodenticide must not be left down for more than 35 days. There is now also a legal obligation to carry out an environmental risk assessment before using a rodenticide. For this reason, UFAW strongly advises non-professionals not to use rodenticides and instead to seek advice from a professional pest controller.

Cholecalciferol rodenticide poisoning

Cholecalciferol is one of the least humane methods of rodent control and should only be used as a last resort.

Cholecalciferol is a non-anticoagulant rodenticide often recommended as an alternative to anticoagulants (ARs) in areas where rats or mice are resistant to ARs (Rodenticide Resistance Action Group) 2021). Cholecalciferol, or Vitamin D3, is the naturally occurring form of Vitamin D, essential for the healthy development and function of mammals. Vitamin D is necessary for the formation of normal bone, but in high concentrations interferes with calcium balance, promoting excessive intestinal absorption of calcium and reabsorption of bone materials, leading to calcification of soft tissues, particularly in the major arteries, heart and kidneys (Defra 2011). As with ARs, poisoned bait must be properly protected from children and, as far as possible, from non-target animals. Outdoors, bait should be placed inside a secure, tamper-resistant bait box unless it can be placed under suitable existing cover. Where bait is used indoors, access by children and any non-target animals must also be restricted. If in doubt, use a bait box.

Cholecalciferol poisoned rodents are likely to experience severe to extreme welfare impacts for days before dying and they most likely remain conscious throughout. Cholecalciferol is one of the least humane methods of rodent control and should therefore only be used as a last resort. Poisoned rodents are likely to experience softening of the bones (osteomalacia) as calcium is extracted into the bloodstream. Kidney failure will lead to build-up of urea crystals in joints. Vomiting, haemorrhaging, abnormal breathing, tremors and coma may occur. Behaviour is compromised, making poisoned animals more vulnerable to predation. Animals will experience pain, breathlessness, nausea, lethargy, weakness, listlessness, anxiety and fear (Baker et al. 2022). Cholecalciferol poisoned rodents die from acute heart or renal failure. The UK’s Pesticide Safety Directorate described this method as ‘markedly inhumane’ as a result (Pesticides Safety Directorate) 1997). Poisoned rats and mice found still alive should be humanely killed immediately and disposed of safely.

Cholecalciferol is toxic to non-target animals and primary non-target poisoning is a risk through access to poison baits. Secondary poisoning of predators or scavenging species (e.g., cats, dogs, badgers and birds) may be possible but is not thought to be a major issue. The effects are difficult to reverse and antidotes are not readily available (Defra 2011). If you suspect a pet or another non-target animal has been poisoned, call the the vet straight away and if possible provide the toxin’s name, strength and the amount the animal has been exposed to, as well as the animal’s weight if that is known.

Advantages

• Cholecalciferol may provide an alternative to anticoagulants when anticoagulant resistance is suspected in the target population
• Secondary poisoning[⁴] is not thought to be a major issue

Disadvantages

• Rodents experience days of pain, breathlessness, fear and anxiety
• Cholecalciferol poisoning is difficult to reverse and antidotes are not readily available
• Anticoagulants present a risk of primary non-target poisoning

Other methods

For completeness, a few other methods are briefly mentioned below.

Goodnature traps – These traps do not capture the target animal - instead they kill by concussion, using a captive bolt. Goodnature A24 traps have been approved for use with ‘rats’ and ‘mice’ in the UK, indicating that in 12 tests ≥80% of animals were rendered irreversibly unconscious within 300 seconds, although the test species are not known. The Goodnature A24 model has passed for black rats (Rattus rattus), but not Norway rats (Rattus norvegicus), under New Zealand’s humane traps standard, which requires that traps cause irreversible unconsciousness within 180 seconds. One study using Goodnature traps caught only one Norway rat and the animal was not fatally wounded and escaped (Ryan 2021).

Stretched rubber band strangulation system – These traps, when triggered, release a stretched rubber ring onto the rodent’s neck, causing death by constricting the windpipe and the blood vessels that supply the brain. Traps of this design for rats and for mice have been approved for use in the UK and have passed for Norway rats under New Zealand’s humane traps standard, which requires that traps cause irreversible unconsciousness within 180 seconds.

Electrocution devices – These devices deliver an electric shock to the mouse or rat that enters them, causing death by cardiac arrest. Two types of electrocution trap for mice have been tested by the German Environment Agency and shown to meet at least the Category B NoCheRo welfare standard, meaning that ≥80% of animals in 12 tests were irreversibly unconscious with 60 seconds and ≥90% were unconscious within 120 seconds

(see details of the NoCheRo standards, which are designed for snap traps, but the standards are the same as used here). The humaneness of these devices will depend upon whether sufficient current runs through the brain and for long enough to cause immediate loss of consciousness from which the animal will not recover prior to death. However, if the animal does not lose consciousness immediately then the shock may cause severe pain prior to the animal’s death from cardiac arrest. At present there is insufficient information to recommend these traps as a humane method.

Phosphine gassing – Phosphine is permitted for gassing rats in their burrows but can only be applied by a trained professional. It cannot be used near occupied buildings. While the welfare impacts are not known they are likely to be very variable. See Phosphine gassing under Managing moles.

Cellulose pellets are available for killing rodents in the USA, but no cellulose products are authorised for use in the EU or UK. Ingestion of cellulose pellets disrupts the digestive system of a rodent resulting in lethal dehydration. This method is likely to have severe to extreme impacts on rodents welfare as they die over a number of days (Baker et al. 2022).

Explosive propane/oxygen mixture - This explosive gas mixture has been used to destroy burrows by blast damage on ignition after it has been pumped into the burrow system. This is NOT a permitted killing method. See the Defra website: http://rodenator.eu/defra-statement  

A note on dependent young

If a lactating female rat or mouse is captured or killed, her dependent young will be left alone to die of starvation or dehydration. Rats and mice can breed all year round so this is a continuous risk. If breeding female rodents are captured or killed, the right thing to do is to try to find and humanely kill any young in the nest.

 

Appendix 1. A note about Dormice

Defra does not consider ‘Dormice’ to be covered by the term ‘mice’ under the Pests Act 1954 or Orders made under it. Dormice are not closely related to other mice: mice are in the family Muridae and Dormice are in the family Gliridae. Although edible dormice (Glis glis) do sometimes inhabit the lofts of houses in certain parts of the country, they cannot be trapped or killed except under licence. All UK Dormice species are included in Schedule 6 of the Wildlife and Countryside Act 1981 (WCA) and a licence is needed from Natural England for “setting in position an article which is of such a nature and so placed as to be calculated to cause bodily injury to any wild animal included in Schedule 6 which comes into contact therewith”. Dormice are protected from any trap, snare or electrical device for killing or stunning, or any poisonous, poisoned or stupefying substance. Furthermore, a licence is needed in order to use various other methods of taking (capturing) which are not calculated to cause injury, e.g., nets (under the WCA, Section 11(2)(a). For a full account of the legal prohibitions on taking and killing animals on Schedule 6 see the WCA Section 11.

Literature cited

Atkinson, R. 2013. Moles. The British Natural History Collection. 135pp. Whittet Books: Stansted, Essex, UK.

Backyard chicken project. 2021. The best way to get rid of rats in your chicken coop. https://backyardchickenproject.com/how-to-get-rid-of-rats-in-the-chicken-coop-the-definitive-guide/.  

Baker, S.E. 2017. A Voluntary Trap Approval scheme to end trap welfare inequality in the UK, Animal Welfare, 26: 131-33.

Baker, S.E., M. Ayers, N.J. Beausoleil, S.R. Belmain, M.  Berdoy, A.P. Buckle, C. Cagienard, D. Cowan, J. Fearn-Daglish, P. Goddard, H.D.R. Golledge, E. Mullineaux, T. Sharp, A. Simmons, and E. Schmolz. 2022. An assessment of animal welfare impacts in wild Norway rat (Rattus norvegicus) management, Animal Welfare, 31: 51-68. https://www.ingentaconnect.com/contentone/ufaw/aw/2022/00000031/00000001/art00005.

Baker, S.E., S.A. Ellwood, P.J. Johnson, and D.W.  Macdonald. 2016. Moles and mole control on British farms, amenities and gardens after strychnine withdrawal, Animals, 6: 39. Special edition on: Ethical and Welfare Dimensions of the Management of Unwanted Wildlife. https://www.mdpi.com/2076-2615/6/6/39.

Baker, S.E., S.A. Ellwood, V.L. Tagarielli, and D.W. Macdonald. 2012. Mechanical Performance of Rat, Mouse and Mole Spring Traps, and Possible Implications for Welfare Performance, PLOS ONE, 7: e39334. https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0039334.

Baker, S.E., and D.W. Macdonald. 2012. Not so humane mole tube traps, Animal Welfare, 21: 613-15. https://www.ingentaconnect.com/content/ufaw/aw/2012/00000021/00000004/art00019?crawler=true.

Baker, S.E., R.F. Shaw, R.P.D. Atkinson, P. West, and D.W. Macdonald. 2015. Potential welfare impacts of kill-trapping European moles (Talpa europaea) using scissor traps and Duffus traps: a post-mortem examination study, Animal Welfare, 24: 1-14.

BASC and Natural Resources Wales. 2016. Grey squirrel control with live capture traps; guidance from the BASC. BASC and NRW, UK. https://www.britishredsquirrel.org/wp-content/uploads/2016/07/Grey-Squirrel-Best-Practice.pdf.

Bat Conservation Trust. Current in 2022. Controlling rats and mice. Bat Conservation Trust, UK. https://www.bats.org.uk/advice/im-working-on-a-building-with-bats/controlling-rats-and-mice.

Bat Conservation Trust. Current in 2022. Rodent control. Bat Conservation Trust, UK. https://cdn.bats.org.uk/uploads/pdf/Rodent-control-advice-sheet.pdf?v=1616693746.

Beausoleil, N.J., and D.J. Mellor. 2015. Introducing breathlessness as a significant animal welfare issue, New Zealand Veterinary Journal, 63: 44-51. https://pubmed.ncbi.nlm.nih.gov/25004795/.  

BPCA. 2020. The use of air guns in pest control; code of best practice, vsn 2. British Pest Control Association, UK. file:///C:/Users/uzdb0086/Downloads/BPCA_Code_of_Best_Practice_Use_of_Air_Guns_in_Pest_Control_V2_August_2020.pdf.

Chartered Institute of Environmental Health. 2014. Code of practice for the use of vertebrate traps. Chartered Institute of Environmental Health: London, UK. https://www.urbanpestsbook.com/download/code-practice-use-vertebrate-traps/.   

Chartered Institute of Environmental Health. 2014. Code of practice for the use of vertebrate traps. http://www.cieh.org/Code_of_practice_for_the_use_of_vertebrate_traps.html.  Chartered Institute of Environmental Health: London, UK.

CRRU UK. 2021. CRRU UK Code of Best Practice; Best Practice Guidance for Rodent Control and the Safe Use of Rodenticides. Revision August 2021. 36 pp. Campaign for Responsible Rodenticide Use UK. www.thinkwildlife.org/code-of-best-practice/. 

Defra. 2011. The Control of Rats with Rodenticides: A Complete Guide to best Practice. http://adlib.everysite.co.uk/adlib/defra/content.aspx?id=000HK277ZX.0B4B1SS7I8E46R.

———. 2021. Our action plan for animal welfare. Defra, UK. https://www.gov.uk/government/publications/action-plan-for-animal-welfare.

Dizney, L., P.D. Jones, and L.A. Ruedas. 2008. Efficacy of three types of live traps used for surveying small mammals in the Pacific Northwest, Northwestern Naturalist, 89: 171-80.

Dubois, S., N. Fenwick, E.A. Ryan, L. Baker, S.E. Baker, N.J. Beausoleil, S. Carter, B. Cartwright, F. Costa, C. Draper, J. Griffin, A. Grogan, G. Howald, B. Jones, K.E. Littin, A.T. Lombard, D.J. Mellor, D. Ramp, C.A. Schuppli, and D.  Fraser. 2017. Consensus principles for ethical wildlife control, Conservation Biology, 31: 753-60. https://conbio.onlinelibrary.wiley.com/doi/10.1111/cobi.12896.

Ellicot, C. 2010. Hauled to court, forced to pay £1,500 and branded a criminal...for drowning a grey squirrel, Mail Online, 20th July 2010. https://www.dailymail.co.uk/news/article-1295883/First-case-kind-Man-told-pay-1-500-guilty-drowning-squirrel.html.

Frantz, S.C., and C.M. Padula. 1983. A laboratory test method for evaluating the efficacy of glueboards for trapping house mice. In Vertebrate Pest Control and Management Materials: 4th Symposium, edited by D. E. Kaukeinen, 209–25. American Society for Testing and Materials: Philadelphia, PA.

Gorman, M, and A Lamb. 1994. An investigation into the efficacy of mechanical mole scarers, Animal Welfare, 3: 3-12.

Health and Safety Executive. 2013. Gassing of rabbits and vertebrate pests. HSE: UK. https://www.hse.gov.uk/pubns/ais22.pdf.

Macdonald, D.W., and P. Barrett. 1993. Mammals of Britain and Europe. Harper Collins: London, UK.

MAFF. 1983. The toxicity of phosphine to the mole (Talpa europaea), unpublished report. Ministry of Agriculture, Fisheries and Food, UK.

Martel, M.J., K.J. MacKinnon, M.Y. Arsenault, E. Bartellas, M.C. Klein, C.A. Lane, A.E. Sprague, and A.K. Wilson. 2002. Hemmorrhagic shock, Journal of Obstetrics and Gynaecology Canada, 24: 504-11.

Mason, G., and K. Littin. 2003. The humaneness of rodent pest control, Animal Welfare, 12: 1-37.

Meehan, A.P. 1984. Rats and Mice: Their Biology and Control. Rentokil Ltd.: Felcourt, East Grinstead, UK.

Natural England. 2010a. The Animal Welfare Act 2006: what it means for wildlife; Technical Information Note TIN072. Natural England, Sheffield, UK. http://www.adlib.ac.uk/resources/000/263/401/TIN072.pdf.

Natural England. 2010b. Moles: options for management and control. Technical Information Note TIN033. Natural England, UK. http://adlib.everysite.co.uk/resources/000/094/907/TIN033.pdf.

———. 2012a. House mice: options for management and control. Technical Information Note TIN034. Natural England, UK. file:///C:/Users/uzdb0086/Downloads/TIN034%20edition%203.pdf.

———. 2012b. Rats: options for controlling infestations. Technical Information Note TIN057. Natural England, UK. file:///C:/Users/uzdb0086/Downloads/TIN057%20edition%205.pdf.

———. 2012c. Rats: control on livestock units. Technical Information Note TIN058. Natural England, UK.

Nicholls, J. 2010. Mole Catching; A Practical Guide. Crowood: Marlborough, UK.

Pesticides Safety Directorate. 1997. Assessment of humaneness of vertebrate control agents. Evaluation of fully approved or provisionally approved products, no. 171. A report by Defra and the PSD. York: UK.

Parrott, D., R. Quy, K. Van Driel, P. Lurz, S. Rushton, J. Gurnell, N. Aebischer and J. Reynolds. 2009. Review of red squirrel conservation activity in northern England. A Report by Fera to Natural England (NECR019). Natural England: Sheffield, UK. http://publications.naturalengland.org.uk/publication/46008.

Pest Management Alliance. 2017. Code of Best Practice: Humane use of Rodent Glue Boards. Pest Management Alliance, UK. https://www.pmalliance.org.uk/codes-of-best-practice/. 

Rodenticide Resistance Action Group. 2021. Anticoagulant resistance in the Norway rat and guidelines for the management of resistant rat infestations in the UK. RRAG, UK. https://bpca.org.uk/write/MediaUploads/Documents/RRAG/2021_CRRU_013_RRAG_Rat_Guideline_2021_web.pdf.

Ryan, EA. 2021. Non-target interactions and humane evaluation of a captive bolt trap on commensal rodents. MSc thesis, University of British Columbia.

Schlötelburg, A., A. Geduhn, E. Schmolz, A. Friesen, S. Baker, N. Martenson, G. Le Laidier, M. Urzinger, O. Klute, D. Schröer, A. Brigham, and M. Puschmann. 2021. NoCheRo-Guidance for the Evaluation of Rodent Traps. Part A Break back/Snap traps. German Environment Agency, Dessau, Germany. https://www.umweltbundesamt.de/publikationen/nochero-guidance-for-the-evaluation-of-rodent-traps.  

UK Government. 2015. Bats: protection and licences. https://www.gov.uk/guidance/bats-protection-surveys-and-licences. UK Government, UK.

UK Government. 2015. Wild birds: protection and licences. https://www.gov.uk/guidance/wild-birds-protection-surveys-and-licences#activities-that-can-harm-birds. UK Government, UK.

Williets, B. 2021. Bournemouth man immersed grey squirrel in freezing water, Daily Echo, 9th October 2021. https://www.bournemouthecho.co.uk/news/19636099.bournemouth-man-immersed-grey-squirrel-freezing-water/.

Yamamoto, K., Y. Yamamoto, and H. Kikuchi. 1983. The effects of drowning media on the lung water content: an experimental study on rats, International Journal of Legal Medicine, 90: 1-6.

[1] To our knowledge, the only country that regulates snap traps is Sweden and apparently this is largely ignored
[2] Secondary poisoning occurs when a predator eats another animal that has been poisoned
[3] Secondary poisoning occurs when a predator eats another animal that has been poisoned
[4] Secondary poisoning occurs when a predator eats another animal that has been poisoned02/0027/210027.pdf