|In a release programme there are many
different people involved, ranging from the veterinary officer responsible for the
animal's health to field biologists undertaking field research on the wild population. It
is vital to have the full cooperation and collaboration of all "stakeholders". A
wide range of information and skills is required for successful planning, logistics and
follow-up observations. In addition there may be people involved who have a legal
responsibility for various parts of the release programme, such as wildlife officers
responsible for implementing the Wildlife
and Countryside Act 1981 and landowners who can restrict access to land.
- Release should be the foremost aim whenever a wildlife casualty is presented.
- Consideration should be made prior to release of the potential risks:
- to the individual animal.
- to the wild population.
- to domestic animals.
- to people.
- 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.
- 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 environment (in terms of climate, habitat and wild population, both same and
different species) must offer the animal a reasonable chance of survival in terms of food
availability, acceptable level of predation, minimal threat from human damage and
- 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.
- Disease screening should be carried out prior to release when appropriate.
- Additionally, there may be an impact on one or more individuals of the local population
in terms of competition when a rehabilitated animal is released other than back into its
- There may be an impact on one or more individuals of the local population in terms of
competition when a rehabilitated animal is released other than back into its original
- The release of animals at a site distant from their origin may mean that the individual
and its offspring are less adapted to the local habitat and environment.
- Domestic animals may be at risk from disease carried by a released animal.
- Humans and domestic animals may be at risk of attack by released tame individuals
of species which would normally avoid people.
- Animals should be released as soon as possible.
- A delay may be required due to inclement weather, temporary food shortage or excessive
- At the time of release the animal must be healthy, fit and able to fend for themselves
in the wild.
- An offence may be committed under the Abandonment
of Animals Act 1960 if a released animal does not have a reasonable chance of
survival (i.e. a chance similar to its non-rehabilitated peers).
- Animals intended for release should be handled and habituated to humans and domestic
animals as little as possible.
- Animals which are habituated to humans and domestic animals may be at greater risk of
being injured by humans, cats, dogs etc.
- Animals which have a reduced fear of humans may in some cases be more likely to attack
humans and domestic animals in search of food.
Choice of Release Site
- Whenever practical, animals should be released at the site where they were found.
- This requires accurate data on where the animal originated (e.g. grid reference, road
name and house number, description in relation to landmarks).
- May not be appropriate or possible if the time in rehabilitation has been prolonged.
- Particularly important for territorial animals - the critical time period before the
animal is likely to be displaced from its territory varies depending on the species and
the time of year.
- Release should occur as soon as possible to reduce the risk of the animal being
displaced from its territory.
Choice of Release Technique
- Consideration should be given as to the benefits of a 'hard' or 'soft' release.
- When possible the release point should be one which can be kept under discrete
observation and such observation should be undertaken following release.
- Factors which may affect the success of a released wild animal include the physical and
sensory fitness of the animal, the behavioural fitness of the animal, food availability,
the timing of release (both time of day and time of year) and weather conditions.
- A good knowledge of the natural history of the species is important for decision-making
regarding the release site, time of day, season, type (hard or soft release) etc.
- Animals should be marked prior to release whenever practical:
- This may involve rings, dye, paint, bands, glued plaques, tattoos, radio collars,
implanted microchips etc.
- N.B. appropriate licences may be required for some forms of
marking/marking of some species.
- Costs of different forms of marking vary widely.
- Allows possibility of monitoring of animals post-release.
- Marking may enable data to be collected on the post-release survival of casualties.
Legalities, Records and Permissions
- Permission of the landowner should be obtained before animals are released on their
- Records should be kept of the details of release:
- Date and time of release.
- Site of release.
- Weather at the time of release (wind direction and speed, rain etc.).
- Type of release (hard/soft).
- Number of animals released (if released in a group).
- Identification marks, if any.
- Follow-up: dates and times seen alive, date found dead, cause of death, if available.
- A post mortem examination (necropsy) should be carried out whenever possible on
released animals which are later found dead.