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This aim of this Code of Practice is to provide information and guidance to vertebrate pest managers responsible for the control of feral donkeys. It includes advice on how to choose the most humane, target specific, cost effective and efficacious technique for reducing the negative impact of feral donkeys.
This Code of Practice (CoP) is adopted nationally. Jurisdictions can apply more stringent requirements as long as they retain the principles set out in these codes. The CoP should only be used subject to the applicable legal requirements (including OH&S) operating in the relevant jurisdiction.
There is an expectation that animal suffering associated with pest management be minimised. Consideration of animal suffering should occur regardless of the status given to a particular pest species or the extent of the damage or impact created by that pest. While the ecological and economic rationales for the control of pests such as the feral donkey are frequently documented, little attention has been paid to the development of an ethical justification as to how these pests are controlled. An ethical approach to pest control requires recognition of and attention to the welfare of all animals affected directly or indirectly by control programs. Ensuring such approaches are uniformly applied as management practices requires the development of agreed National Standard Operating Procedures (NATSOPs) for pest animal control. These NATSOPs are written in a way which describes the procedures involved for each control technique as applied to each of the major pest animal species. While SOPs address animal welfare issues applicable to each technique, a Code of Practice (CoP) is also required which brings together these procedures into a document which also specifies humane control strategies and their implementation. CoPs encompass all aspects of controlling a pest animal species. This includes aspects of best practice principles, relevant biological information, guidance on choosing the most humane and appropriate control technique and how to most effectively implement management programs.
This code is based on current knowledge and experience in the area of feral donkey control and will be revised as required to take into account advances in knowledge and development of new control techniques and strategies.
Definitions and Terms
Pest animal – native or introduced, wild or feral, non-human species of animal that is currently troublesome locally, or over a wide area, to one or more persons, either by being a health hazard, a general nuisance, or by destroying food, fibre, or natural resources (Koehler, 1964).
Welfare – an animals’ state as regards its attempts to cope with its environment (Broom, 1999). Welfare includes the extent of any difficulty in coping or any failure to cope; it is a characteristic of an individual at a particular time and can range from very good to very poor. Pain and suffering are important aspects of poor welfare, whereas good welfare is present when the nutritional, environmental, health, behavioural and mental needs of animals are met. When welfare is good suffering is absent (Littin et al., 2004).
Humane Vertebrate Pest Animal Control – the development and selection of feasible control programs and techniques that avoid or minimise pain, suffering and distress to target and non-target animals (RSPCA, 2004).
Best Practice Management – a structured and consistent approach to the management of vertebrate pests in an attempt to achieve enduring and cost-effective outcomes. ‘Best practice’ is defined as the best practice agreed at a particular time following consideration of scientific information and accumulated experience (Braysher, 1993).
From an animal welfare perspective, it is highly desirable that pest control programs affect a minimum number of individuals and that effort is sustained so that pest densities always remain at a low level. Over the last decade, the approach to managing pest animals has changed. Rather than focussing on killing as many pests as possible, it is now realised that like most other aspects of agriculture or nature conservation, pest management needs to be carefully planned and coordinated. Pest animal control is just one aspect of an integrated approach to the management of production and natural resource systems. Most pests are highly mobile and can readily replace those that are killed in control programs. Unless actions are well planned and coordinated across an area, individual control programs are unlikely to have a lasting effect. When planning pest management, there are some important steps that should be considered (after Braysher & Saunders, 2002).
From an animal welfare perspective, it is highly desirable that pest control programs affect a minimum number of individuals and that effort is sustained so that pest densities always remain at a low level. Over the last decade, the approach to managing pest animals has changed. Rather than focussing on killing as many pests as possible, it is now realised that like most other aspects of agriculture or nature conservation, pest management needs to be carefully planned and coordinated. Pest animal control is just one aspect of an integrated approach to the management of production and natural resource systems. Most pests are highly mobile and can readily replace those that are killed in control programs. Unless actions are well planned and coordinated across an area, individual control programs are unlikely to have a lasting effect. When planning pest management, there are some important steps that should be considered (after Braysher & Saunders, 2002).
Implementing effective and humane pest control programs requires a basic understanding of the ecology and biology of the targeted pest species and in some cases those species affected directly (non-targets) or indirectly (prey species) by a control program. It is also essential to understand the impact created by the pest i.e. what is the problem? Managers should take the time to make themselves aware of such information by reading the recommended texts at the end of this code of practice. A brief summary follows. This information is extracted from the publications ‘Pest Animals in Australia: A Survey of Introduced Wild Mammals’ by G. Wilson et al. (1992) and ‘The Mammals of Australia’ by R. Strahan (ed.) (1995) and also from a fact sheet titled ‘Feral Horse (Equus caballus) and feral donkey (Equus asinus)’ by the Natural Heritage Trust, Department of Environment and Heritage (2004).
The first donkeys were brought to Australia in 1866. They were used widely as pack and draught animals until the early 1900’s when they were superseded by motorised transport. As transport improved donkeys were liberated and large populations built up. In the 1920’s and 1930’s large numbers of feral donkey populations were reported and by 1949 the donkey was sufficiently numerous to be declared a pest in Western Australia.
The feral donkey is well-adapted to arid regions and is most abundant in the Kimberley pastoral district of Western Australia and the Victoria River area of the Northern Territory. Lower densities are found in the semi-arid regions and deserts of central and western Australia. Although absolute numbers are difficult to estimate, there are thought to be between 2 and 5 million feral donkeys in Australia.
Feral donkeys are both grazers and browsers and feed during the day on a wide variety of plants. They can subsist on coarser vegetation than horses and in the Kimberley region are attracted to perennial tussock grasslands. Large mobs of up to 500 animals congregate on residual sources of water and favoured grazing areas during the dry season. During the wet season they disperse in groups of less than 30 individuals to take advantage of the abundant growth.
Feral donkeys are seasonal breeders, with births occurring between September and February. Females reach sexual maturity in their second year and can produce one young per year under favourable conditions. In northern Australia more that 75 per cent of females breed annually. Annual population growth can approach 25 cent under good seasonal conditions or when recovering from a culling program. As a population recovers and higher densities are attained, females continue to breed but their capacity to rear their offspring declines. This decline is related to increasing competition for favoured forage species; females being ultimately unable to procure a diet sufficiently nutritious to meet the demands of lactation. Mortality of juveniles eventually increases to more than 60 per cent in the first six months of life, with less dramatic increases in mortality in adults. At this stage, population growth stalls and equilibrium with the food supply is established until disturbed by a shift in seasonal conditions or by culling.
Donkeys may compete with stock for water during the dry season. They congregate around watering points and are said to deny stock access. They may also compete with stock for pasture and denude ground cover and contribute to erosion. The effect of donkeys on native species is unknown but habitat destruction may be a problem.
A small number of feral donkeys are mustered or trapped and sold for pet meat and some are domesticated. However, the main management tool used is aerial culling whereby donkeys are shot from helicopters with high-powered rifles. Large scale culling campaigns are regularly carried out in many parts of Northern Australia. Between 1978 and 1987, 180 000 donkeys where shot in the Kimberley region and 83 000 where shot between 1981 and 1984 in the Victoria River area.
Despite considerable control efforts, feral donkey problems are continuing. In the 1990’s trials incorporating the use of Judas donkeys were successful and this is now the primary means of control in some areas. The Judas technique utilises radio tracking equipment attached to a Judas donkey to locate other feral donkeys. In the Kimberley region, this method has led to the complete eradication of donkeys on some pastoral leases.
By necessity, any control effort must be sustained. There are three essential requirements for a pest control technique – necessity, effectiveness and humaneness. The best strategy is to develop a plan which maximizes the effect of control operations and reduces the need to cull large numbers of animals on a regular basis.
This involves:
Feral donkey control techniques have the potential to cause animals to suffer. To minimise this suffering the most humane technique that will achieve the control program’s aims must be used. This will be the technique that causes the least amount of pain and suffering to the target animal with the least harm or risk to non-target animals, people and the environment. The technique must also be effective in the situation where it will be used (e.g. aerial shooting will have little effect in forested areas). It is also important to remember that the humaneness of a technique is highly dependant on whether or not it is correctly employed. In selecting techniques it is therefore important to consider whether sufficient resources are available to fully implement that technique.
It may not be economic for a property to be independent in equipment and labour for feral donkey management. Group schemes and cooperative effort provide economies of scale and social benefits that encourage sustained effort. Cooperative control effort can also encourage financial support from governments.
Techniques for the control of feral donkeys mostly include aerial shooting and ground shooting and sometimes exclusion fencing. ‘Judas’ donkeys fitted with radio collars are also used to help locate difficult to find groups of donkeys during eradication programs. Trapping at water and mustering are also potential methods of control however they have variable effectiveness and can be expensive and time-consuming over large areas. Other measures such as fertility control and immobilisation followed by lethal injection could be used; however these methods are not practical given that many donkeys live in the vast rangelands of central Australia.
Different techniques are best suited to particular situations depending on issues such as mob size and age structure, geography and season. Aerial culling by properly trained and accredited shooters using approved procedures is considered to be a humane way to reduce feral donkey numbers over large areas. The process is quick and eliminates the stresses of mustering, yarding and transportation for slaughter.
Cost-effectiveness, humaneness and efficacy for each control technique are useful in deciding the most appropriate strategy. A brief evaluation of the humaneness of control techniques follows:
Fertility control is seen by some as a preferred method of broad-scale feral donkey control as it offers a potential humane and target specific alternative to lethal methods. However, hormones to control fertility are difficult to administer to large numbers of free-roaming donkeys and there is no long-acting or permanent drug presently available; therefore annual treatment would be required. Also, where large scale impact reduction is required, fertility control alone would be ineffective due to the long life of donkeys. Consequently, its application is not currently feasible for most Australian conditions where feral donkey numbers are high and their domain extensive.
The use of exclusion fencing is generally regarded as a humane, non-lethal alternative to lethal control methods. However, fencing of large areas is expensive to construct and maintain and is difficult in rugged terrain. Strategically placed fences can direct donkeys from areas where they are difficult to control, such as hill country, into areas where they are more easily controlled. They can also restrict access to sensitive areas, and exclude donkeys from some water points to concentrate them at others where they can be trapped. Unfortunately, in some situations where donkeys are denied access to their regular waterholes, they may not move on to an alternative water supply and can die of thirst. Therefore regular inspections are necessary so that any lingering donkeys can be shot or allowed to drink.
Exclusion fencing can also have negative effects on non-target species by restricting access to natural watering points, altering dispersion and foraging patterns, and causing entanglement and electrocution. It can also create a significant hazard to wildlife in the event of a bushfire. The fences constructed to exclude feral donkeys should allow wildlife such as kangaroos and dingoes to go under the fence.
With this method, a low-charge dart containing a tranquiliser is injected to immobilise approachable donkeys, which are then euthanased with an injection of barbiturate. Although this method is seen as more humane than most other lethal methods, it is very costly, labour intensive, requires veterinary supervision and is therefore unsuitable for broadscale control.
This technique is not commonly used since feral donkeys are said to be difficult to muster because of their habit of breaking away when driven. Mustering will inevitably cause stress and anxiety in the donkeys and has the potential to cause serious injury. When mustering is used, it should be carried out when conditions are cool or mild to avoid heat stress. Feral donkeys should be handled quietly without force to avoid panic and trampling. The tail end of the mob should set the pace rather than being forced to keep up with the leaders. Distances that the donkeys have to be mustered should be kept to a minimum e.g. by using portable yards.
This technique is not commonly used since in many areas donkeys have access to numerous water sources. When trapping is used, it may not be as stressful and potentially dangerous as mustering is, given that the donkeys are not driven into the trap but go in quietly of their own accord. However, there is still the potential for welfare problems during the process of holding, handling and transferring the donkeys from the trap to a vehicle for transport.
To minimise the possibility of starvation and stress, all traps must be inspected at least once daily. Donkeys must be provided with water at all times and appropriate feed must be made available if captured donkeys are to be held more than 24 hours. More frequent checking may be necessary during extreme weather conditions. Traps should be constructed to provide donkeys with shade and shelter and should be large enough to avoid overcrowding.
Capture and handling should be avoided when females are foaling or have dependent young at foot. Foals that do not accompany their mother into the trap may be separated and die of starvation or if trapped can get trampled underfoot.
Donkey traps can have a negative impact on native non-target species (especially macropods) by inadvertently trapping them and also by excluding them from water sources. This impact can be minimised by using a suitable yard design that incorporates fencing material and gates that allow wildlife to escape if trapped. Also, the fencing used to protect alternative water sources from donkeys when trapping should allow access to wildlife species.
Mustering, capture and handling increase stress in feral donkeys as they are not used to confinement or close contact with humans. Exposure to prolonged or excessive stress causes severe physiological effects and can result in the following conditions:
The removal of trapped feral donkeys off-property for sale to abattoirs involves additional stress to animals, particularly when long distance travel is involved. Therefore, the more humane option may be to destroy the animals on the property where they are caught.
Capture, handling and restraint of donkeys for use as Judas animals can cause anxiety and sometimes pain or injury if they struggle to escape. Repeatedly being isolated and having to find other donkeys may cause fear and anxiety as donkeys are highly social animals. Tracking and the nearby shooting of cohorts may also be another source of distress.
The lightest collar/transmitter available should always be used (< 5% of the body weight of the animal). The collar must be properly fitted for the comfort and safety of the animal. It should fit snugly enough to prevent it from coming off or chafing the neck, but it must also be sufficiently loose as to be comfortable and not interfere with swallowing or panting. Efforts should be made to reduce the possibility of the collar getting caught up in vegetation.
Shooting is considered more humane than capture and removal as the animals are not subject to the stresses of mustering, yarding, and long-distance transportation.
Shooting can be a humane method of destroying feral donkeys when it is carried out by experienced, skilled and responsible shooters; the animal can be clearly seen and is within range; and the correct firearm, ammunition and shot placement is used.
Wounded animals must be located and killed as quickly and humanely as possible. If lactating mares are shot, reasonable efforts should be made to find dependent foals and kill them quickly and humanely. Ground shooting is not suited to rough country as wounded animals cannot be effectively pursued and would suffer unnecessarily.
Aerial shooting of feral donkeys from a helicopter can be a humane control method when it is carried out by highly skilled and experienced shooters and pilots; the correct firearm, ammunition and shot placement is used; and wounded animals are promptly located and killed. Shooting from a moving platform can significantly detract from the shooter’s accuracy therefore helicopter shooting operations do not always result in a clean kill for all animals. Follow-up procedures are essential to ensure that all wounded animals are killed.
With aerial shooting of donkeys, ‘double-tap’ chest shots (2 quick shots) are most frequently made, as the heart and lungs are the largest vital area and an accurate shot is more achievable particularly within the range of unusual angles encountered when shooting from above. Although death from a chest shot may be more certain, compared to an accurate head shot, a shot to the chest does not render the animal instantaneously insensible and time to death is slower.
Table 1: Humaneness, Efficacy, Cost-effectiveness and Target Specificity of Feral Donkey Control Methods
Control Technique | Acceptability of technique with regard to humaneness* | Efficacy | Cost-effectiveness | Target Specificity | Comments | ||
Exclusion fencing | Acceptable | Limited | Expensive | Can be in certain situations | Expensive, therefore impractical for large scale application. Fencing can be effective for small, critical (economically or environmentally) areas, though the maintenance costs are high. | ||
Fertility control | Conditionally Acceptable | Not currently effective | Expensive | Target-specific | Not currently available. Not practical for large scale control. | ||
Immobilisation and lethal injection | Acceptable | Not effective | Expensive | Target-specific | Not practical for large scale control. | ||
Mustering | Conditionally acceptable | Limited | Cost-effective. Can be expensive if helicopters are used. | Target-specific | Efficient and cost-effective where donkeys are present in high densities, terrain is relatively flat and donkey prices are high. Welfare concerns associated with capture and transport of donkeys. More costly than trapping. | ||
Trapping | Conditionally acceptable | Limited | Cost-effective | Can have an impact on non-target species. Trapped non-target species must be removed as quickly as possible to avoid undue stress. Traps at natural water holes may restrict access by native species. Donkey traps should be designed so that most wildlife can go through fences or under gates. | Cannot be used in some areas where there are numerous watering holes. Most effective when conditions are dry and there are few waterholes around where donkeys can drink. Cost-efficient method of capture. | ||
Ground shooting | Acceptable | Not effective | Not cost -effective | Target-specific | Labour intensive, only suitable for smaller scale operations. Impractical in good seasons when there is lots of water around and in rugged country where large scale control is required. | ||
Aerial Shooting | Conditionally acceptable | Effective | Relatively expensive. Can be cost-effective when donkey density is high | Target-specific | Suitable for extensive areas and inaccessible country. Most effective way of achieving quick, large scale culling. | ||
Use of Judas donkeys | Conditionally acceptable | Effective | Relatively cost effective compared with searching for donkeys from helicopters or on foot | Target-specific | Can be a useful adjunct to other control methods. Effective if local eradication is the aim. Requires expensive equipment and skilled operators |
* Acceptable methods are those that are humane when used correctly.
* Conditionally acceptable methods are those that, by the nature of the technique, may not be consistently humane. There may be a period of poor welfare before death.
* Methods that are not acceptable are considered to be inhumane. The welfare of the animal is very poor before death, often for a prolonged period.
For regional variations on control techniques refer to local legislation and regulations. For additional examples refer to the National Standard Operating Procedures (NATSOPs).
NATSOPs are currently available for the following feral donkey control methods:
All those involved in pest animal control should familiarise themselves with relevant aspects of the appropriate federal and state or territory legislation. The table below gives examples of some of the relevant legislation. This list is by no means exhaustive and is current at September 2012.
Commonwealth
|
Agricultural and Veterinary Chemicals Code Act 1994
Environment Protection and Biodiversity Conservation Act 1999 |
ACT
|
Pest Plants and Animals Act 2005
Medicines, Poisons and Therapeutic Goods Act 2008 Animal Welfare Act 1992 Nature Conservation Act 1980 Animal Diseases Act 2005 Prohibited Weapons Act 1996 Firearms Act 1996 Environment Protection Act 1997 |
New South Wales
|
Prevention of Cruelty to Animals Act 1979
Pesticides Act 1999 Rural Lands Protection Act 1998 National Parks and Wildlife Act 1974 Threatened Species Conservation Act 1995 Wild Dog Destruction Act 1921 Game and Feral Animal Control Act 2002 Deer Act 2006 Non-Indigenous Animals Act 1987 Exhibited Animals Protection Act 1986 |
Northern Territory
|
Animal Welfare Act
Territory Parks and Wildlife Conservation Act Poisons and Dangerous Drugs Act |
Queensland
|
Animal Care and Protection Act 2001
Health (Drugs and Poisons) Regulation 1996 Land Protection (Pest and Stock Route Management) Act 2002 Nature Conservation Act 1992 |
South Australia
|
Animal Welfare Act 1985
Natural Resources Management Act 2004 Controlled Substances Act 1984 National Parks and Wildlife Act 1972 Dog Fence Act 1946 Fisheries Management Act 2007 |
Tasmania
|
Animal Welfare Act 1993
Vermin Control Act 2000 Poisons Act 1971 Agricultural And Veterinary Chemical (Control of Use) Act 1995 Nature Conservation Act 2002 Police Offences Act 1935 Cat Management Act 2009 |
Victoria
|
Prevention of Cruelty to Animals Act 1986
Catchment and Land Protection Act 1994 Agriculture and Veterinary Chemicals (Control of Use) Act 1992 Drugs, Poisons and Controlled Substances Act 1981 Wildlife Act 1975 Flora and Fauna Guarantee Act 1988 National Parks Act 1975 |
Western Australia
|
Biosecurity and Agriculture Management Act 2007
Animal Welfare Act 2002 Agriculture and Related Resources Protection Act 1976 Wildlife Conservation Act 1950 |
Other relevant legislation
|
Firearms Acts
Occupational Health and Safety Acts Dangerous Goods or Substances Acts Dog Acts Civil Aviation Acts |
Note: copies of the above legislation and relevant regulations may be obtained from federal, state and territory publishing services.
Feature image: Herd of donkeys by Jeffrey Miles
Sharp T and Saunders G (2012) National Code of Practice for the humane control of feral donkeys. PestSmart website. https://pestsmart.org.au/toolkit-resource/code-of-practice-feral-donkeys accessed 06-11-2024