- understanding species behaviour and ecology
- species conservation
- population management
- evaluating methodologies for control
- understanding the role of wildlife in disease transmission.
Wildlife studies vary in their invasiveness and impact on the animals being studied. In all circumstances, researchers should seek to minimise any negative impact on the welfare of animals involved. Good animal welfare practice for wildlife research is characterised by the same features as laboratory-based research, however different approaches and procedures may be needed for wild animals compared with laboratory-bred animals.
Wildlife research is usually conducted with free-living animals in their natural habitat or with wild-caught animals in various captive settings (e.g. laboratory, zoo, aquarium, sanctuary). Rarely, wildlife species are purpose-bred under laboratory conditions similar to those used for animal models. Animals should not be taken from their natural habitat unless animals bred in captivity are unavailable or unsuitable for the scientific purpose. Taking animals from the wild for scientific purposes is regulated by legislation.
Many wildlife studies focus on conservation and management, with the aim of learning about the ecology of a population in the field. In such cases, minimising disturbance to the animals is important for the scientific validity of the research as well as for good animal welfare.
Some field studies require altering the animals' habitat or behaviour as a goal of the study, whilst others require monitoring the animals in response to a change in habitat. In such cases, it is important to minimise disturbance, both to the animals around the study site and to the animals under investigation.
Many field studies involve manipulating the study animals involving capture, marking or additional procedures, or a combination of these, which can cause distress. Capture, marking, radio tagging and collecting physiological data (e.g. blood or tissue samples) can also have delayed consequences, such as a reduced probability of survival and reproduction. It is therefore vitally important to carry out such procedures according to 'best practice' and to monitor the animals for potential adverse effects. Pilot studies may be used to assess the potential environmental disruption of fieldwork and follow-up studies may be used to monitor the success of the study and any adverse effects caused to the animals.
Researchers should take into account the social structure and behaviour of the species under investigation. The most obvious example is the dependence of young on maternal care. For species with a complex social organisation, removing a critical member of the social group can impair the well-being of the remaining group members. Such considerations may be pertinent even when the removal of animals is temporary.
Even purely observational studies, where there is no manipulation of the animals, can raise ethical concerns with regard to animal welfare and/or conservation. For example, human observation can disturb normal animal activities such that animals abandon their territories, home ranges or young. Making trails/transects through habitats to access, observe and census animals can also cause disturbance. Researchers should consider such issues when designing their studies. Camera traps can sometimes be used to avoid disturbing the animals either by trapping or direct observation.
In general, wild-caught animals should be kept in captive conditions that conform as closely as possible to their natural habitat (e.g. in such respects as light intensity, food etc.). Length of time in captivity and location of release are important additional considerations for animals being returned to the wild. Prolonged time in captivity may result in the released animal being rejected by its conspecifics and losing access to essential resources (e.g. badger's sett), which may compromise its ability to feed or fend for itself. Animals should always be returned to the exact point of capture.
The 3Rs are an integral part of the UK Animals (Scientific Procedures) Act 1986, amended 2012 (ASPA), which regulates the use of vertebrates and cephalopods, including wildlife species, in procedures with the potential to cause pain, suffering, distress or lasting harm. The ASPA also requires that the likely benefits of the research, to humans, animals or the environment, are weighed against the likely harms to the animals involved.
The 3Rs and harm/benefit assessment are relevant also to wildlife research that is not regulated by the ASPA but which, nonetheless, has the potential to compromise the welfare of the study or non-study species. The 3Rs should always be considered as part of the design and conduct of wildlife studies.
Replacement does not often apply to studies aimed at understanding the behaviour and ecology of wildlife species, because the animals themselves are the objects of study. However, in silico techniques, such as computer modelling, are used for population studies, including those aimed at evaluating methods of lethal/fertility control, investigating animal movements and predicting disease spread.
Many of the principles and techniques used to reduce the numbers of animals used in biomedical research are applicable to wildlife research. These include:
- using appropriate and efficient experimental designs, e.g. factorial designs to explore the effects of several variables in one experiment; sequential and multivariate statistical methods; repeated measures designs; phasing of experiments
- estimating minimum sample size necessary for statistical significance and for adequate statistical power using information from the literature, pilot data, or both
- keeping the number of replicates/experimental units (e.g. individual animals, cages of animals, social groups) to the minimum for the power level required
- utilising statistical programmes that indicate when sufficient data have been collected for a significant result
- avoiding repeating studies, unless it is essential for the purpose or design of the project
- sharing data and resources (e.g. biological and genetic samples) and publishing results, preferably in free access formats.
Animal use can also be reduced by:
- minimising the number of procedures to be carried out (e.g. trapping once to gain data for different parts of the study)
- utilising species/gender/age-specific experimental designs (e.g. using species specific baits, or trapping at specific times or locations to minimise non-target capture).
In contrast to most laboratory studies, sample size is not easy to control in field studies. For example, it may be necessary to trap 100 animals to find 40 that meet the age and sex requirements for a study. In addition, there may be external factors, such as weather conditions, that may affect the data that can be collected. It is important to consider these factors when designing field studies.
Assessing potential sources of harm to study and non-study species and how these will be eliminated or minimised should form part of all wildlife research proposals. In many cases, any negative impact on animal welfare can be reduced by careful experimental design and choosing the least invasive techniques. Issues to consider include:
- capture/trapping - best practice guidelines are available (e.g. from the British Association for Shooting and Conservation, American Society of Mammalogists)
- handling and restraint - handling wild animals should always be kept to a minimum; the correct techniques are not necessarily the same as those recommended for laboratory animals
- marking by banding, tagging, branding, tattooing and toe, ear or tail clipping
- attaching an external, or implanting an internal, radio transmitter - the device should be within the recommended percentage of weight of the study animal and also be suitable for the animal's lifestyle (e.g. external transmitters may not be very useful for animals that squeeze through small openings, such as bats)
- medical/surgical interventions using anaesthetics and immobilising agents - anaesthesia is often needed to prevent distress or injury when handling or fitting non-invasive devices (e.g. radio collars)
- sampling hair, feathers, scales, milk, skin scrapings, stomach contents
- sampling blood and other body fluids - often non-invasive samples, such as saliva or faeces, can be used in place of blood or plasma
- methods for measuring body weight, respiration rate, heart rate, pulse rate, body temperature and body lengths
- euthanasia - humane killing methods in the field are not necessarily the same as those in Schedule 1 of the ASPA; researchers should be trained in the most appropriate field methods for the animals likely to be encountered (i.e. not just the target species)
- close examination of den sites, nests, etc. when this involves handling and/or removal of young animals, eggs or other objects
- removal to novel environments
- housing and maintenance in captivity - for most wild animal species there are no specific guidelines in the Home Office code of practice on care and accommodation; consider outdoor housing where appropriate
- environmental manipulation
- changes to diet and access to food/water - wild animals may not be able to use drinking bottles or to recognise certain novel foods; knowledge of the natural diet and behaviour and close monitoring of food and water intake is essential
- manipulating social grouping
- social deprivation
- methods of attracting animals, e.g. playback of calls, provisioning, baiting
- frequency and duration of human observation - consider using remote video surveillance
- habituation to humans
- disturbing interactions between species (e.g predator-prey), within species (e.g competition) and between species and habitat.
Wildlife species used in research vary greatly in their body size, physiology and behaviour. The methods and equipment used should be appropriate to the species and cause the least distress. It is therefore recommended to consult species-appropriate literature and to seek the advice of those who are experienced with the particular species of interest and familiar with its response to disturbance, sensitivity to capture and restraint, and, if necessary, requirements for captive maintenance. Anyone capturing animals should be trained and competent in humane methods of capture, handling and release, and in any scientific procedures used, to minimise the impact on animals and their environment.