Standard Operating Procedures for Grey Squirrel Control - Scottish Wildlife Trust
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Standard Operating Procedures
for
Grey Squirrel Control
1 August 2020
Contents
1. Context ......................................................................................................................................... 3
2. Health and Safety ......................................................................................................................... 3
3. Training ......................................................................................................................................... 4
4. Method of capture – Live-trapping .............................................................................................. 4
5. Approaching the trapped animal .................................................................................................. 5
6. Methods of despatch .................................................................................................................... 5
6.1. Cranial concussion .............................................................................................................. 5
6.2. Kania 2000 spring trap........................................................................................................ 6
6.3. Shooting.............................................................................................................................. 7
6.4. Lethal injection ................................................................................................................... 8
7. Confirmation of death .................................................................................................................. 8
8. Other methods of despatch not for use under SSRS .................................................................... 9
8.1. Gassing ............................................................................................................................... 9
8.2. Drowning ............................................................................................................................ 9
8.3. Poison ................................................................................................................................. 9
8.4. Drey poking ........................................................................................................................ 9
8.5. Spring or tunnel trapping ................................................................................................. 10
9. Disinfecting the Trap................................................................................................................... 10
2 August 2020
1. Context
Grey squirrel control is a legal activity which does not need to be licensed. The following provides a
brief list of legal instruments which set specific provisions to govern associated aspects of the
practice.
Legal instrument Summary of provisions
Wildlife & Countryside Act Section 14: Makes it illegal to release, or allow to escape to the
1981 (as amended in wild, any captive grey squirrel
Scotland under the Wildlife Keeping and Release and Notification Requirements (Scotland)
and Natural Environment Order 2012: Makes it an offence to keep a grey squirrel in
(Scotland) Act 2011) captivity except under licence
Wild Mammals (Protection) Makes it illegal to subject grey squirrels to wilful acts of cruelty
Act 1996 or abuse
Animal Health and Welfare Provides for duty of care for animals in captivity (live-trapped
(Scotland) Act 2006 animals). Makes it an offence to inflict, or allow others to inflict,
cruelty or abuse on a grey squirrel held captive
Control of Pesticides Provides guidance on the specific deployment in enclosed
Regulations 1986 spaces of the anticoagulant warfarin for grey squirrel control
The Spring Traps Approval Governs the type of spring traps which may be legally used for
(Scotland) Order 2011 as the capture of grey squirrels
revised by The Spring Traps
Approval (Scotland)
Amendment Order 2018
This is not intended as a definitive guide to the legislation and you should refer to the original
legislation if you need more details.
2. Health and Safety
Your health and safety, and that of other members of the public, is of paramount importance. The
work required may involve some activities in remote and exposed locations and you should ensure
that you have appropriate clothing/footwear and provisions for these circumstances. If you are
working alone, you must ensure that you notify someone of your whereabouts at all times during
the work. You must also ensure that this person is informed when you return from trapping. Where
possible, and appropriate, mobile phones should be carried.
Scottish Wildlife Trust employer’s and public liability insurance will cover volunteers working on the
Saving Scotland’s Red Squirrels project’s behalf for personal injury sustained or third-party damage
caused during the course of the work. The following Scottish Wildlife Trust health and safety
documentation should be made available for all volunteers working on behalf of the Project where
appropriate:
RISK ASSESSMENT – GREY SQUIRREL CONTROL
LONE WORKING RISK ASSESSMENT - GREY SQUIRREL CONTROL
SCOTTISH WILDLIFE TRUST - LONE WORKING POLICY
It is required that risk assessments are carried out for each new outdoor area in which work is
carried out.
It is also required that volunteers complete the Scottish Wildlife Trust Volunteer Registration Form.
3 August 20203. Training
You will be given a thorough briefing on the work required, including live-trapping and despatch of
grey squirrels before you conduct any work. You will also be expected to undertake additional
training, supplied by the Project, where you need this to build on existing skills.
There are particular health and safety implications if you are shooting trapped animals. This method
should only be used where you have explicit permission of the landowner, preferably in writing.
Shooting must comply with all the relevant UK firearm regulations and you will be expected to
conform to the BASC code of practice. You must make clear your intention to use this method to the
person co-ordinating your work in order that we ensure you are given the appropriate training and
guidance if required.
4. Method of capture – Live-trapping
1. Identify suitable locations in or near suitable habitat for trapping based on sightings or signs of
grey squirrels.
2. Using your knowledge of the area, identify the risks to any non-target species and position the
traps to minimise these. This may include raising the trap off the ground, although it is
recommended that this should not be more than one metre.
3. Prepare a secure, flat base for the trap.
4. Cover the trap with cardboard, plywood or plastic sheeting to provide shelter from the
elements and to provide a dark refuge for the captive animal. Traps on the ground can be
further covered by logs, leaves or stones to help stabilise it and to help disguise it. Placing two
twigs vertically on the ground at the trap entrance, or fixing wire across the entrance to
reduce the size of the opening, also helps to minimise the risks of non-target species such as
pheasants. However, ensure that these do not interfere with the door closing.
5. Traps should be pre-baited if you are trying to control grey squirrels where they are well
established. This is unnecessary when trying to catch a single animal and, in this case, traps
should be set and baited immediately. To pre-bait, secure the trap door open (using wire or a
locking clip) and bait with whole maize for a minimum of five days, and preferably one or two
weeks. It is not possible to distinguish between food eaten by red or grey squirrels in areas
with both species. However, only squirrels will remove the soft germ of the maize, discarding
the outer kernel and this may give an indication that there are grey squirrels if red squirrels
are known not to be present in the area.
6. Set traps should be baited with whole maize. Where there is a lot of natural food available,
you may prefer to use peanuts or hazel nuts as an added attraction for grey squirrels.
However, these will also increase the likelihood of catching red squirrels, while peanuts will
also increase the risk of attracting pine martens and badgers. Bait should be placed at the
back of the trap with a small amount (no more than 6 grains of maize) at the door to
encourage the animals in.
7. Traps must be visited once every 24 hours, but the project recommends visiting them twice
daily where there is a risk of catching red squirrels or other non-target species (morning and
dusk). You must lock traps open or shut when you are not able to visit them regularly (illness
or holidays). Do not attempt to trap in severe weather as squirrel activity is likely to be low
and there is an added risk of not being able to visit the trap regularly.
8. Non-target animals should be released immediately when you find them in the trap1. You
must review the trapping if you regularly catch more non-target species than grey squirrels.
Under these circumstances, a licence may be required to cover trapping of other protected
1The exception to this would be in the instance when an invasive non-native species such as mink is caught; in this case the
animal should be despatched by the recommended method for that species.
4 August 2020species. This can be arranged, as appropriate, by the SSRS Project Manager. Measures which
may be taken to minimise trapping of red squirrels in areas of co-existence include using
maize bait, setting covered traps on the ground where possible, reducing trapping frequency
and moving traps to areas which offer the best source of grey squirrel food (increasing the
probability of catching grey squirrels).
9. Trapped grey squirrels must be handled humanely in accordance with the Animal Health and
Welfare (Scotland) Act 2006. Grey squirrels cannot be released under the Grey Squirrels
(section 14(1a) of the Wildlife and Countryside Act 1981, as amended in Scotland by the WANE
(Scotland) Act 2011) and must be destroyed humanely (see section 6).
5. Approaching the trapped animal
1. Sprung traps can often be identified from a distance as the door will be closed. However, as
the location or cover of the trap may prevent this, you should always approach traps directly
and calmly to avoid undue stress to any captive animal.
2. You should try to confirm the species present in the trap without touching the trap or with
minimal disturbance to avoid distress to the captive animal. Non-target animals must be
released immediately.
6. Methods of despatch
There are a number of methods available to kill grey squirrels humanely. All have both legal and
practical implications and it is important that you are aware of these to ensure that grey squirrel
control is undertaken legally and humanely.
Not all of the methods available are practical under field conditions or applicable to red squirrel
conservation. The following presents the minimum Standard Operating Procedures for methods
recommended by the project and a brief explanation of others which are not recommended. It is
important that you are fully trained in the method which you choose to use in the field before
undertaking any control work on behalf of the Project. This should be discussed at the outset with
the person co-ordinating your work. Anyone undertaking grey squirrel control on behalf of the SSRS
project will be expected to meet the requirements of this training before undertaking any control.
Further information on this can be obtained from your local SSRS Conservation Officer (contact
details at https://scottishsquirrels.org.uk/).
In most cases, grey squirrels will be captured in relatively isolated locations. However, where this is
not the case, e.g. urban gardens, you may prefer to move the animal to a less public place before
despatching it. This is perfectly acceptable as long as you do this as set out under the guidance for
transporting animals in Section 6.3 Lethal Injection.
6.1. Cranial concussion
Guidance on this method is also available in Forestry Commission Practice Note 4.
Equipment:
A heavy blunt “priest” or metal baton capable of delivering a blow of sufficient force to
cause a depressed skull fracture;
5 August 2020 Medium weight hessian sack2;
Thick gloves (optional).
1) Place a hessian sack tightly over the entrance to the trap taking care not to leave any gaps and
secure with a bungee cord. Roll the length of the sack up to create a tunnel for the animal to
move down once released from the trap. Release the door to allow the animal to move from
the trap into the sack. You can use thick gloves to help prevent being scratched or bitten;
2) Once the squirrel has moved into the sack, roll the sack up behind it to prevent it turning
around and manoeuvre the animal into the corner of the sack. Ensure that the head is secure
in one corner, not covered by the tail and free of excess sacking;
3) When the animal is secured, locate the back of the head and, ensuring it is against a hard
surface, using the heavy fishing priest, deliver a rapid blow of sufficient force to fracture the
skull.
Death must always be confirmed. Once the animal is immobile, open the sack and check it as set out
in section 7.
6.2. Kania 2000 spring trap
The Kania 2000 spring trap fixed to a live cage-trap has been approved by the Scottish Government
as a method for humane despatch of a captive grey squirrel as an alternative to cranial concussion.
This dispatch method is clean and efficient and is largely blood free and reduces the chances of the
squirrel escaping or the operator being bitten or scratched.
Note that the authorisation relates only to this particular trap used in accordance with Section 10 of
the Northern Ireland Squirrel Forum’s code of practice https://www.daera-
ni.gov.uk/sites/default/files/publications/daera/Grey%20Squirrel%20Control_Code%20Of%20Practic
e%20~%202016%20edit%20v6.3.%20%20Northern%20Ireland%20Squirrel%20Forum%20NISF.pdf
Controllers are reminded that any captured grey squirrels would be temporarily under the control of
man and any subsequent treatment would be subject to the Animal Health and Welfare (Scotland)
Act 2006.
Under the Scottish Government approval for use of the Kania 2000 for despatch at a live-trap, there
should be no modification of the spring mechanism. Modifications of the housing may be made to
improve effectiveness.
Equipment
Kania 2000 spring trap.
The Kania 2000 spring trap requires minor modifications to its housing in order to allow it to
be fitted tightly to the entrance of the standard squirrel or mink cage trap, as shown below.
It is also advisable to modify the Kania 2000 housing by fitting a Perspex window to the end,
to encourage the squirrel to run toward the light, but this is not entirely necessary.
Attachment bungees or springs (for attaching to cage live-trap)
Trap comb
Dowel or stout wire for lifting cage trap door
A heavy blunt “priest” or metal baton plus hessian sack as a backup despatch option
2Alternative bags have been considered and dismissed as inappropriate. The hessian sack provides strength to avoid
being bitten whilst providing a darkened environment to minimise stress to the animal involved. Clear or open-weave
material, including fine mesh onions sacks, may improve sight for the operator but may also increase the anxiety of the
animal, although this can be offset by the benefits of a more efficient and confident kill. Conical restraints should only be
used where these mask the animal’s eyes to prevent increased stress.
6 August 2020The Kania 2000 attached to a standard squirrel trap, two springs hold the two traps close together to avoid
escapes.
1) Restrain the squirrel at the back of the cage-trap using the trap comb.
2) Arm the spring trap and attach it securely using the springs or bungee cords to the cage trap.
3) The cage-trap door can then be lifted and locked open using a wooden dowel, and the trap
comb released.
4) The squirrel should be left to move at its own speed toward the spring trap and be
dispatched cleanly.
5) The operator must have a means of cranial concussion to hand for use in the unusual event
that the squirrel is not hit cleanly by the kill bar, in order to deliver a secondary blow to
ensure swift death.
Death must always be confirmed. Once the animal is immobile, open the trap and check it as set out
in section 7.
6.3. Shooting3
Shooting in a trap should only be carried out with an airgun or air pistol and must adhere to relevant
UK air weapon laws.
In Scotland, the Air Weapons and Licensing (Scotland) Act 2015 made it an offence from 31
December 2016 to use, possess, purchase or acquire an air weapon in Scotland without holding an
air weapon certificate. https://www.scotland.police.uk/about-us/finance/service-fees-and-
charges/firearms/air-weapon-licensing/.
Equipment
Air rifle or air pistol powered by CO2 or compressed air, including those with a spring-cocking
mechanism. Minimum 0.177 caliber in, preferably 0.22 caliber. Repeat weapons may be
preferred where operator preference is to deliver a rapid second shot to ensure immediate
death. Where carcases are to be supplied to raptor centres, it is advisable to use steel pellets
as many such places refuse carcases killed by lead shot.
Cage crush (comb) x2
3 The guidance applies only to trapped animals. Where free-ranging squirrels are being shot, different firearm
regulations apply and controllers must comply with the British Association for Shooting and Conservation Code
of Practice. This will include being able to demonstrate safe handling of firearms.
7 August 20201) Ensure weapon is loaded before approaching the caged animal to minimise the stress to the
captive animal;
2) Ensure trap is stable and shot is clear. The cage crushes should be used to restrict the
movement of the animal, positioning these alternately on either side to contain the animal,
and ensure a swift and humane shot;
3) Deliver a shot to the head, aiming at the top or back of the skull. Alternatively, the shot may
be aimed at the back of the head with the barrel pointing slightly forward to propel the shot
into the brain stem.
Death must always be confirmed. Once the animal is immobile, follow the guidance in section 7.
6.4. Lethal injection
Sodium pentobarbitone is the commonly used and accepted drug for this purpose. It is controlled
under Schedule 3 of the Misuse of Drugs Regulations 2001 and is available only to licensed
practitioners. For this reason, this method can only be administered by a licensed person (e.g.
Veterinary surgeon, SSPCA inspector). SSRS project staff cannot use this method and, unless a
licensed person is available on site, project staff will be responsible only for delivering the animal to
licensed personnel in an appropriate and humane state.
1) Where possible, arrangements to euthanise the animal should be made with the nearest
licensed practitioner to minimise the travel time for the animal.
2) Animals should, where possible, be left in the cage to transport. Where this is not possible,
this should be notified to the project team in advance of any control work starting and the
SSRS project will provide suitable containers (conforming to the regulations set out in The
Welfare of Animals (Transport) Order 1997).
3) Animals should always be accompanied by SSRS staff and confirmation received from the
licensed practitioner that all animals have been despatched. Animals should not be left
unattended on the assumption that they will be disposed of later.
7. Confirmation of death
It is the responsibility of the operator to ensure that the method is delivered effectively and
humanely. Death must be confirmed for each animal in all circumstances. Signs of death include:
Loss of rhythmic breathing
Loss of heart rate
Onset of rigor mortis
Rigor mortis is the only single indicator of death. Loss of breathing and heart rate may be difficult to
detect if shallow or weak respectively. If there is any doubt about death, a second method must be
used to kill the animal.
It is essential that each operator receive training in recognising the signs of death. Signs of
unconsciousness (including irreversible unconsciousness) and insensibility include loss of posture,
fixed, dilated pupils, lack of response when shining a light in the eye, absence of the blinking reflex
and loss of co-ordinated movement. It is preferable that each operator is also able to distinguish
these to ensure full confidence in delivering and confirming a quick and humane death for each
animal.
8 August 20208. Other methods of despatch not for use under SSRS
8.1. Gassing
This method, used in the USA, involves the use of specially-designed euthanasia chambers which fit
around standard cage traps. The most commonly used gases are CO2 (with or without inert gases)
and carbon monoxide (CO). Other anaesthetic gases may also be employed.
Anaesthetic gases are classed as ‘prescription only medicines’ and are not available to the general
public. CO2 is approved as a Commodity Substance under the Control of Pesticides Regulations 1986
(as amended) and is approved for trapped rodent pests. CO is not approved for use.
An overdose of gas can be considered a reliable method of despatch subject to the effective delivery
of the lethal concentration and suitable chamber being used. Both of these are technically feasible.
However, for Health and Safety reason, this method should not be employed under lone working
conditions. It also involves transport of significant amount of equipment (i.e. gas chamber and gas
source) and costs would be prohibitively high if used to despatch a significant number of animals
under field conditions. For these reasons, it is not considered a viable method recommended for
SSRS project staff.
8.2. Drowning
A despatch method can only be considered legal under the Animal Health and Welfare (Scotland) Act
2006 if it delivers a “reasonably swift and humane” death. Drowning of a grey squirrel may
therefore open the perpetrator to risk of prosecution, as the time taken for squirrels to die under
this method can be expected to be minutes of unacceptable suffering.
Given the other more swift and humane methods available, drowning is not considered a humane
method of despatch and is not condoned under this project.
8.3. Poison
The licence to use Warfarin for squirrel control in the external environment was withdrawn by the
EU in September 2014. No other poisons are approved for this use in the UK.
8.4. Drey poking
Drey poking involves disturbing nesting squirrels with long poles and shooting the emerging animals.
Dogs may be used to despatch animals which are not killed outright but which fall to the ground.
Drey poking is most effective if conducted in late February/early March when there are no leaves on
the trees.
However, it can be difficult to identify a grey squirrel drey from that of a red squirrel, and the species
may use each other’s dreys, so this method is not recommended in areas of red-grey co-existence.
Thus drey poking cannot be used in many places in Scotland unless a grey squirrel has been seen
entering a drey.
Although shooting can be a quick and effective method of killing animals humanely, failure to place
accurate shots risks injuring the animals and causing pain and distress. Therefore drey-poking and
shooting are not recommended as means of grey squirrel control under this project.
9 August 20208.5. Spring or tunnel trapping
Spring traps are regulated under the Spring Traps Approval (Scotland) Order 2011 as revised by The
Spring Traps Approval (Scotland) Amendment Order 2018. These traps are designed to kill on
capture using the spring mechanism to deliver a killing blow.
Spring traps rely on delivering a fatal strike. Reports on trap effectiveness varies between the design
and only those traps which have the potential to pass international standards of rendering an animal
insensible should be used. Effectiveness of spring traps relies also on their position, with traps in
trees offering more success in improving the targeting of grey squirrels. However, this introduces
H&S considerations when placing traps above head height.
However, as the trap does not discriminate between species, it is illegal to use these where there are
red squirrels or other Schedule 6 protected species at risk.
Due to the risks to non-target species, their use cannot be supported under the SSRS project. The
exception is the use of the Kania 2000 in conjunction with a live-capture cage-trap (Section 6.2
above).
9. Disinfecting the Trap
After a trap has been occupied it should be sprayed (an empty kitchen/bathroom spray cleaner
bottle is perfect for this) with a disinfectant such as Trigene or Virkon S and left to dry - the trap
should not be rinsed. Using a disinfectant is essential in preventing the spread of disease between
red squirrels or between any other non-target animals caught.
Virkon S is the disinfectant of choice because it is a wide-range disinfectant that is effective against
squirrelpox virus (and many other organisms), but does not cause toxic build-up in the environment
when used in the field.
References
Forestry Research (2019) Controlling Grey Squirrels in forests and woodlands in the UK.
UKFSTN022_M71DPeR%20.pdf; ISBN 978-1-83915-004-3
https://www.forestresearch.gov.uk/research/controlling-grey-squirrels-forests-and-
woodlands-uk/
Northern Ireland Squirrel Forum’s code of practice on use of the Kania trap for despatch at a live-
trap https://www.daera-
ni.gov.uk/sites/default/files/publications/daera/Grey%20Squirrel%20Control_Code%20Of%20Practic
e%20~%202016%20edit%20v6.3.%20%20Northern%20Ireland%20Squirrel%20Forum%20NISF.pdf
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