TECHNIQUE

Accommodation of Casualty Mice & Voles (Wildlife Casualty Management)

Summary Information
Type of technique Health & Management / UK Wildlife Casualty Management/ Techniques:
Synonyms and Keywords N.B.  This information should be read in association with Wildlife Casualty Accommodation which contains background information together with links to the Electronic Library and Organisations (UK Contacts). The related Species pages contain similar linkages.
Description This page has been prepared for the "UK Wildlife: First Aid and Care" Wildpro module, and is designed for the needs of the following species: Apodemus flavicollis - Yellow-necked mouse, Apodemus sylvaticus - Wood mouse, Micromys minutus - Harvest mouse, Mus musculus - House mouse,  Arvicola terrestris - European water vole, Clethrionomys glareolus - Bank vole, Microtus agrestis - Field vole, Microtus arvalis - Common vole.

These species are within the family Muridae.

Transport Container:

  • A secure container is required.
    • e.g. a small plastic aquarium with a mesh-ventilated lid incorporating a trap-door.
    • Plastic ice cream tub or margarine container with small holes in the lid for ventilation.
    • Biscuit tin, with small holes in the lid for ventilation.
    • Jam-jar, with small holes in the lid for ventilation.
  • One or two pieces of kitchen roll to line the floor of the container.
  • N.B. Cardboard boxes are not suitable due to the high risk of escape through holes gnawed in the box.
  • Provision of bedding such as torn or shredded paper may be useful to decrease stress, particularly if transporting in a clear container such as a jam-jar.
  • (B151, B224, V.w5, V.w26)

Short term (Immediate/Emergency) Accommodation:

  • Escape-proof tanks with leaf litter/bark/shredded paper for hiding in.(D24)
  • Small plastic aquaria with a plastic mesh lid, preferably with a trapdoor in the lid for ease of changing food and water with minimal risk of the occupant escaping. (B151)
  • Sand or shavings are suitable as a substrate. (B151)
  • Objects such as rocks may be provided for hiding under.(B151)
  • N.B. a cardboard tube e.g. from a kitchen roll provides a hiding place and, with both ends blocked, facilitates transfer from one container to another.(B151)

Medium-term (Hospitalisation) Accommodation:

  • Escape-proof tank such as a glass aquarium or a small plastic aquarium with a plastic mesh lid, preferably with a trapdoor in the lid for ease of changing food and water with minimal risk of the occupant escaping.
  • Floor should be covered with an absorbent material to absorb urine, and should be cleaned out at least once a week, with obvious wet patches removed every day.
  • Sand or shavings are suitable as a substrate. (B151)
  • Provide leaf litter, bark or shredded paper to hide in.(D24)
  • Objects such as rocks may be provided for hiding under.(B151)
  • Cardboard tubes e.g. from kitchen roll provides a hiding place and, with both ends blocked, facilitates transfer from one container to another.
  • (B151, D24)
  • Tall tanks with vertically-orientated vegetation are preferred for Micromys minutus - Harvest mouse. (D40)

Long-term (Rehabilitation and Permanent) Accommodation:

  • Glass aquarium or metal (galvanised iron or steel) cage.
  • A wire mesh lid (no more that 0.25 inch mesh for Micromys minutus - Harvest mouse) provides good ventilation
  • Floor should be covered with an absorbent material to absorb urine, and should be cleaned out at least once a week, with obvious wet patches removed every day.(B16.2.w2)
  • Cage cleaning for mice should be required only about every two weeks and should not be more frequent than necessary due to the disturbance related to the loss of odour cues. (B169.24.w24)
  • Nesting material (e.g. shredded paper, rags, hay, shavings) should be provided, sufficient for burrowing in. 
  • Provide a nest box. 
  • Furnishings such as bricks, stones, branches etc.
  • Minimum 12-15 hours light per day.
  • Relative humidity 50-60%.
  • Tall tanks with vertically-orientated vegetation are preferred for Micromys minutus - Harvest mouse. (D40)
  • Details of tank furnishings for keeping Micromys minutus - Harvest mouse are available in: Harvest Mice - Husbandry Guidelines
  • Water voles are best bred in outdoor enclosures with one pair of voles per enclosure. (P29.2000.w1)
  • (B16.2.w2, B169.24.w24, P29.2000.w1, D40)
Appropriate Use (?)
  • Short-term (Immediate / Emergency) Accommodation is designed to be used for a short period of time only, e.g. prior to examination, to allow basic first-aid to be carried out, while an animal requires intensive care, or while specialist accommodation is being prepared.
    • The most important requirements are warmth, quiet and dark or dim lighting.
  • Medium-term (Hospitalisation) Accommodation is designed for the short-term care of individual animals or groups of animals, particularly during treatment and rehabilitation.
    • Hospital accommodation is commonly constructed with hygiene and easy cleaning as the main considerations, but the specific needs of the patients, including behavioural needs, should also be considered.
  • Long-term (Rehabilitation and Permanent) Accommodation facilities for wildlife are generally larger and more complex than accommodation designed only for temporary occupancy.
    • In general this type of accommodation is not suitable for animals which require daily treatment.
    • A period in rehabilitation accommodation may be particularly important when an animal has been hospitalised for some time.
Notes
  •  Mice can be kept group housed but consideration must be given to the sex of the animals within the group to prevent a population explosion which complicates release.
  • If an animal is maintained in long-term care accommodation for a substantial period of time, the animal must have some form of environmental enrichment to encourage natural behaviours (possibly through food presentation techniques, cage furniture that encourages activity, or play items that would be found in its native environment). This is to reduce the risk of boredom as the animal becomes accustomed to its enclosure and the possible development of behavioural problems. (V.w6)
Complications/ Limitations / Risk
  • Cardboard boxes are not suitable for containing rodents due to the high risk of escape through holes gnawed in the box.
Equipment / Chemicals required and Suppliers
  • Aquaria/vivaria of various sizes and makes are available from pet shops. 
Expertise level / Ease of Use
  • No particular expertise is required.
Cost/ Availability
  • Containers suitable for accommodating these species are widely available and not particularly expensive.
Legal and Ethical Considerations
  • Accommodation for casualty wild animals should be designed to minimise the stress on the animal and to minimise the risk of injury to that animal.
  • A wild animal in captivity is protected under the same welfare legislation as domestic animals, e.g. Protection of Animals Acts 1911-2000; under this legislation it is an offence to treat a captive animal cruelly or to cause it unnecessary suffering.
    • This includes an obligation to provide proper attention and care.
    • The keeper has a duty to keep all wildlife casualties in a fit manner, in accommodation of a size which allows reasonable movement and with an environment suitable for its normal way of life.
    • (J35.147.w1, P19.2.w1, D27, D28)
  • Accommodation which does not fulfil the physiological and psychological requirements of the animal and results in an inadequate level of fitness at the time of release may seriously compromise the survival ability of that animal. Release of an animal which is unfit may be an offence under the Abandonment of Animals Act 1960. (J35.147.w1, W5.Jan01)
  • Risks to human health, both physical and risk of zoonotic illness must be minimised: Health and Safety at Work, etc. Act 1974
  • An offence may be committed under article 14 of the Wildlife and Countryside Act 1981 if a species on Schedule 9 of that Act, or a species not ordinarily resident in the UK is allowed to escape from accommodation in which it is being housed.
  • See: Legislation relating to Wildlife Casualties.
Author Debra Bourne
Referee Becki Lawson and Suzanne Boardman
References

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