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 Release 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.
Pre-release:
Release assessment/criteria:
Released mammals:
- Must be able to recognise, catch, manipulate, consume and digest their natural diet.
- Must be capable of normal locomotion (movement) and have sufficient fitness for
sustained activity.
- Must have adequate sensory ability (sight, smell, hearing, touch).
- Must be of an appropriate weight for the age, sex, and time of year.
- Must have a satisfactory hair coat.
- Must show appropriate wariness of humans and domestic animals.
- (P19.1.w10,
P24.233.w11,
J35.147.w1,
D27)
- Appropriate health checks should be carried out prior to release. A careful
assessment (risk analysis) must be made as to the risks of released animals introducing
novel pathogens (disease agents) into the wild population/environment.
- These pathogens may have been acquired from domestic animals, other wildlife casualties
or humans whilst the animal was in captivity.
- The health checks should be designed to
minimise the risk that pathogens posing a threat to wild populations of this or other
species will be introduced into the environment when the animal is released.
- (V.w5,
V.w6,
P28.2000.w1,
J15.20.w3)
Selecting a
release site:
- Release back into the site the animal came from if known, or the nearest safe location.
(D27)
- Release programmes for harvest mice use carefully selected and protected sites. (D40)
Timing of release:
- Release predominantly diurnal species in daytime and nocturnal species at night; see
individual species pages for information on activity patterns.
- Release during a period of fine weather whenever possible.
Type of release:
Hard release is generally used when releasing wildlife casualties
of small prey species.
However,
it is important to recognise that these species rely on the presence of burrows/runs for
protection from predators. Release in the absence of such burrows/runs may considerably
increase the chance of the animal being caught by a predator in the short term.
Soft
release is used routinely when animals of these species are released during organised
captive breeding and release programmes.
(P28.2000.w1)
Mice and voles:
- May be released into hedgerows, cat-free gardens, graveyards, golf-courses etc. (B224)
- Release by placing the animal's sleeping box under a hedge away from a road.(B199)
- Release during a period of fine weather .(V.w26)
Micromys
minutus - Harvest mouse:
- Release near field edge with tall grasses for nest building sites.(B151)
- Release by placing the animal's sleeping box under a hedge away from a road.(B199)
- Release during a period of fine weather.(V.w26)
- Information on keeping and release of harvest mice (Micromys
minutus - Harvest mouse) may be obtained from Penny Rudd.(V.w18)
Arvicola
terrestris - European water vole:
- Contact The
Mammal Society for details of any local water vole projects. (B151)
- Mike Jordan (V.w30)
may be contacted regarding the captive breeding and release programme for water voles. (V.w6)
- Release in an aquatic environment.(B224)
- Release near a stream.(B199)
- Release in good water vole habitat, at side of small rivers or canals.(B151)
|
Appropriate Use (?) |
- Soft release is particularly important for hand reared animals, particularly of species
which need to learn about their surroundings (e.g. food sources) and/or learn survival
skills such as hunting.
- Soft release is also suitable for animals which have been in care for prolonged periods.
- Soft release may compensate for difficulties of newly released animals finding food and
shelter, particularly in a new environment and/or at a time of reduced physical
fitness/stamina.
- Hard release is most appropriate for animals which have been held in captivity for only
a short time, for adult animals and for animals being released back into their own
territory.
- The individual animal must, at the the time of release, be healthy, have a reasonable
level of fitness and be able to fend for itself in the wild.
|
Notes |
- Diurnal species should be released in the morning, giving them a full day to explore and
look for food and shelter before nightfall.
- Nocturnal species should be released at night.
- Release should preferably take place during a period of fine weather.
- Releasing back into the site the animal came from may assist in ensuring that it is
released into a suitable habitat. (B199)
- Information on keeping and release of harvest mice (Micromys
minutus - Harvest mouse)may be obtained from Penny
Rudd (V.w18).
- Mike Jordan (V.w30)
may be contacted regarding the captive breeding and release programme for water
voles.
|
Complications/ Limitations / Risk |
- Mice and voles should not be released near busy roads or in the territory of a known
hunting domestic cat.
- Hard release is least appropriate for juveniles which have been hand reared,
particularly species for which learning about their environment and/or social skills are
important.
- Hard release may also be inappropriate for adults which have been maintained in
captivity for prolonged periods and/or are being released at a site distant from their
original location.
- Released animals may be at risk of contracting disease if there is an ongoing disease
problem in the wild population at the time of release.
- The wild population may be at risk from novel pathogens (disease agents) carried by a
rehabilitated animal. These pathogens may pose the greatest threat to free-ranging
populations if the animal is to be released at a site distant from its original location
therefore increasing the likelihood of spread of disease. It is important to remember that
the casualty wild animal may have acquired disease from domestic animals, other wildlife
casualties or humans whilst in captivity.
|
Equipment / Chemicals required and Suppliers |
|
Expertise level / Ease of Use |
- Knowledge of the natural history of the species and its habitat requirements are
important for release of mice and voles into an appropriate site at an appropriate time;
this is particularly important for the release of rare species such as Micromys
minutus - Harvest mouse and Arvicola
terrestris - European water vole.
|
Cost/ Availability |
- Considerable time investment may be required to find suitable release sites for Micromys
minutus - Harvest mouse and Arvicola
terrestris - European water vole.
- Costs of appropriate health screening.
|
Legal and Ethical Considerations |
|
Author |
Debra Bourne |
Referee |
Becki Lawson and Suzanne Boardman |
References |
- J15.20.w3,
J35.147.w1,
B151,
B199,
P19.1.w10,
P24.233.w11,
P28.2000.w1,
D27,
D40,
V.w5,
V.w6,
V.w18,
V.w26,
V.w30
- J35.147.w1,
B156.21.w21,
B223,
W5.Jan01
|