Wildlife research in the field
- Capture of animals (number of animals, location of captures, methods)
- Handling (skill, safety, blood collection, stress)
- Marking (purpose for marking, type of mark)
- Release (time and location of release)
- Wildlife Regulations
Research involving animals in their natural habitats is important. Such research may involve observations on natural history, ecology of species, community ecology or applied environmental studies. Many of these studies involve the capture, handling and manipulation of animals. Common studies revolve around understanding the reproductive cycles or diets of various animal species.
What factors need to be considered in making an application to the AEC to characterise the reproductive cycle and diet of a wild animal?
When working with wild animals, the Code requires that you consider options that do not involve capture of animals. Thus, you should ask:
Is it really necessary to capture the animals to answer the ecological question that you have posed?
You should consider non-capture methods for characterising diet including:
- collection and analysis of faeces
- direct observation of feeding
- study of museum specimens
Considerations
Information on reproductive cycles may be obtained by observation. However other issues must be considered, including: •time of year
- disturbance of habitat
- influence on other species in the area
- use of techniques (e.g. decoys such as bird calls) to bring animals out
- ease of observation
Planning
You have determined that the animals need to be caught. You need to consider issues of reduction and refinement.
All impacts that occur from the time of capture until the end of the study need to be considered.
Reduction relates to the experimental design. Careful experimental design may allow reduction in the number of animals required for the study. Refinement relates to the details of the experimental methods. Select methods that will minimise impact on individual animals at ALL stages of the experiment.
How can the numbers you need to capture be kept to a minimum?
You need to design your experiment to capture the smallest number of animals to answer your question by considering the:
- location of your study site
- placement of your traps within the study site
- frequency of your visits to the study site
- frequency of your visits to your traps
Refinement
How can you design your experiment to minimise impact on the animals?
Many issues need to be considered, some being more relevant to one species than another species.
Issues of particular importance include:
- capture method
- environmental stress
- biological impact
Method
What is the best method for capture of your species?
You need to consider:
- how quickly you can capture your required sample
- how long each animal will spend in the trap
- is there any danger imposed on the animal by the capture method
- are non-target species likely to be captured
- are trapped animals likely to be subjected to increased risk of predation, disease or parasites as a result of being captured?
Ultimately, is there a better capture method?
Environmental Stress
How can you minimise the impact of heat, cold, dehydration, drowning, or starvation on the animal?
Should trapping periods be targeted to particular seasons, weather conditions or times of day?
How frequently should you check your traps to minimise impacts on captured animals but not frighten potential captures away from traps?
Biological Impact
Your capture of an animal may affect its future life in the wild, which in turn may adversely affect your study.
Even a brief period of capture may alter the animal’s social standing in the population, which may influence its ability to survive and reproduce.
Capture of individuals with dependent young may influence the survivorship of the young. How can you refine your methods to minimise or eliminate these effects?
Introduction
Once you have captured your animal, you need to handle it safely to perform the necessary procedures for your study.
Consider how your methods can be refined to minimise impact on the animal.
In addition, you need to consider the skill of the handler, safety for both the investigator and the animal, and sampling methods.
Skill
Skilled handling will:
- minimise stress on the animal
- reduce danger to the animal and the investigator
- reduce the time that the animal is handled
- enable the most accurate measurements and samples to be taken
Safety
The safety of both the animal and the investigator is important.
Skilled handling is important in minimising stress on the animal, but will also reduce the chances of the investigator being injured.
Animal
Safety for the animal is paramount.
Consideration should be given to the possibility of:
- trap injuries,
- injuries that could be sustained during handling,
- contamination of the animal by diseases or parasites transmitted by the trap, investigator or other equipment.
Investigator
Safety for the investigator is important and all procedures should conform to Occupational Health and Safety standards.
Dangers for the investigator may be direct from the animal in the form of injury (bites, scratches etc.) or indirectly from the environment or from zoonose diseases such as Salmonella or hydatids.
Special care should be taken when dealing with blood or faeces.
Refinement
There is a large variety of measurements and/or samples that can be made on individual animals.
Methods of measurement may include blood collection, stomach flushing, laparoscopy to observe reproductive status and killing the animal for tissue sampling, as well as direct linear measurements.
Consideration should be given to the collection of voucher specimens for museums, as discussed in the Code.
There are some general considerations that can be given to sampling/measurement, although there will be many more specific items to consider in individual cases or environments. Some general considerations include:
- should the animal be sedated or anaesthetised during handling?
- are the equipment and methods being used appropriate to the species?
- what is the reproductive condition of the individual?
Blood Collection
Prior to collecting blood, you should consider:
- site of collection
- method of collection
- volume of blood to be collected
- frequency of collection
These issues may vary from species to species.
Stress on the Animal
Capture and handling will be stressful to most animals. Stress may influence your study and the consequences of stress need to be considered carefully.
For example, capture and handling normally result in increased concentrations of stress hormones such as corticosterone. Elevation in corticosterone may suppress concentrations of reproductive hormones such as testosterone, or they may influence the behaviour of the animal after it is released.
Stress is now known to influence animals that traditionally have been thought to be little affected by handling. For example, the impact of capture and handling of American alligators is now know to extend for up to 48 hours.
Marking Method
The method of marking of your animal will depend on a number of factors, many of which will depend on the species being investigated.
Additionally, your choice of mark should be influenced by your reason for marking the animal and the potential impact of the mark on the animal and on your study.
General considerations include:
- permanency of mark
- trauma
- direct influence of the mark or tag
- size of tag
- legibility
Permanency of Mark
Is it necessary to provide a permanent mark?
Trauma
How traumatic will it be for the animal to be marked?
For example, will toe-clipping be less traumatic than freeze branding or electronic tags?
How easy it is to apply the mark?
Direct Influences
Is the mark likely to make the animal more visible to predators, increase its chances of disease, reduce its future reproductive success or have some other negative impact on the animal that will also affect the long-term viability of your study?
Tag Size
Is your tag likely to be too heavy or to interfere with the animal in other ways?
Would, for example, a transponder provide a better tag for your study than a radio transmitter or a spool of cotton?
Legibility
It is important that the mark or tag be easily read.
Can the tag be read from a distance without recapturing the animal?
How is tag loss or mutilation likely to influence your results?
Introduction
Having captured, marked and collected samples from your animal, you must release it. Release may not be a simple matter and may involve risk to the animal. Risks may involve anything from mild stress to serious risk of death.
Things that you should consider include:
- time of day
- environmental conditions
- location
- time for recovery from procedures
Time of Day
Time of day is an important consideration in deciding when to release animals.
For example, careful consideration should be given to when and where to release nocturnal animals. In some cases it may be more appropriate to release some nocturnal animals into shelters during the day than keep them until the next night. Similar considerations are appropriate for diurnal animals (e.g. into a nest or shelter).
Care should be exercised in choosing when and where to release animals that may overheat quickly (including small reptiles,frogs and mammals) or those that require warmth (e.g. small mammals and birds).
Environmental Conditions
Environmental conditions at the time of possible release may influence stress of release.
In addition to considerations of time of day on when and how animals should be released, weather conditions may be important. Release of animals in heavy rain may not be appropriate or, indeed, release of animals (e.g. frogs) may not be appropriate if it is not raining.
Location
The micro- and macro-environment in which the animal is released should be carefully considered.
In most circumstances, it is important to release animals into sheltered positions.
If animals are captured in one place and measured and/or samples taken in another place, they should be returned and released at an appropriate place close to where they were initially captured. The exact place of release may be modified by considerations of time of day or environmental conditions.
Recovery Time
It may not be appropriate for animals to be released immediately after they have been measured and/or sampled. Time of holding of animals will depend on the procedures.
Considerations include whether or not the animal was sedated or anaesthetised, how much blood was taken and whether there was any handling trauma.
You may need other licences in addition to AEC approval to conduct research on wildlife. Licences may be required to capture and handle the animals or merely to conduct research on public land. Agencies from which licences may be required include:
- National Parks and Wildlife Service
- Department of Agriculture
- State Forests
- Fisheries Department
- Local government agencies - Some local government agencies require investigators to have a licence issued by them to conduct research on their properties. Enquiries should be made to individual councils.