Effective and humane feral deer control programs that adhere to animal welfare standards are critical in achieving landscape scale outcomes. Coordinating control efforts among neighbouring properties is highly effective in managing widescale deer populations. Available control tools, such as shooting from helicopters or the ground, along with the use of traps, exclusion fencing, spotlights, thermal imaging equipment, and noise suppressors (in accordance with State regulation), can improve the efficiency of control measures while prioritising the welfare of the animals.
Ground culling (shooting) can be an effective tool for reducing small to moderate numbers of feral deer, being the main control option in peri-urban and urban areas. Ground shooting is time consuming, labour intensive and requires skilled operators. It is often done at night from a vehicle or foot, assisted by spotlights, night vision or by thermal scopes, drones, or with detection dogs. Suppressors (in accordance with State regulation) reduce the noise of ground shooting, enabling more feral deer to be shot at one time, whilst reducing noise disturbance for residents.
Recreational shooting where the motivation is purely to source an animal for meat or trophy will generally not remove sufficient feral deer numbers to reduce impacts or meet control program goals in many parts of Australia.
Aerial culling (shooting) from helicopter is an effective, and often the primary way to rapidly reduce large numbers of feral deer over thousands of hectares, particularly in inaccessible areas and for eradication of small, sparse or cryptic populations. Recent aerial programs have been particularly successful with the assistance of high quality thermal detection technology.
Skilled shooters and pilots follow strict protocols and accreditations (e.g. FAAST training system in NSW) to ensure culls are humane and safe. Operational plans are approved by the Civil Aviation Safety Authority. Programs require thorough planning, including community engagement and land access agreements from all landholders. All aerial culling must adhere to the National Standard Operating Procedure: Aerial shooting of feral and wild deer.
Thermal technology is advancing quickly, and is likely to play an increasingly important role in surveillance and control in Australia. It includes thermal scopes attached to firearms (for improved accuracy) and thermal video cameras either attached to drones (for detection, and to inform ground shooters) or hand held from a helicopter or vehicle (for a wide field of view).
Thermal cameras detect the difference between the body heat of deer and the cool air and ground. High quality thermal cameras can detect many more animals in vegetated areas, than a human eye can.
Exclusion fencing can protect environmental or agricultural assets from intensive impacts of feral deer, where shooting or trapping is not effective or feasible. Fencing is often used to protect newly planted trees from being browsed or trampled. Fencing can also limit the movement of feral deer across the landscape or guide them into a trap.
Exclusion fencing is expensive to establish and maintain. Feral deer are experts at jumping over and pushing under fences. To exclude them, fences should be a minimum of 1.9 metres high, with strong posts, mesh pegged to the ground, with strainer wires to keep the mesh taut, and sometimes with an overhang at the top.
Commercial harvesters can remove moderate numbers of feral deer and use them for human or pet meat. Harvesters are often used in coordinated programs as a first step, to knock down feral deer numbers until harvesting is no longer feasible in the area. Then professional shooters, landholders or volunteers can manage the remaining low numbers of feral deer.
Deer traps are used to remove feral deer in areas where shooting is not effective, permitted or feasible, and where feral deer regularly visit. Traps are one of the only tools available in urban areas where shooting is problematic.
Traps vary in size from entire paddocks to a few square meters. Some designs are commercially available, and others are purpose built by land managers on their land. Trap door mechanisms can be activated by remote triggers (mobile phone), trip wires or the entrance may be a one-way earthen ramp. Traps are generally left open for days or weeks to habituate the feral deer, then the trap door mechanism is set. Operators need to provide shade, food and water for trapped deer, and set traps must be checked daily.
The deer aggregator is a new control tool being trialled in Queensland, New South Wales, Tasmania and South Australia.
It is a feeder designed to aggregate feral deer to a desirable location, for more effective ground shooting at a reliable location. The aggregator enables deer to access feed while excluding access by native animals, such as kangaroos and possums.
The aggregator will be useful in peri-urban areas or locations where the aim is to attract deer away from one area to an alternate area to assist in increasing numbers of deer targeted by ground shooting.
Development of this control tool is a collaboration between the Centre for Invasive Species Solutions and Department for Primary Industries South Australia.
The below methods can be implemented at a localised scale to target a small effected area or impacted valuable asset. These methods will not reduce the number of feral deer nor will it be a long term solution, as the deer will move onto surrounding areas.
Lights, noises and chemical smells can be effective at a small scale, particularly along known road crossings or valued assets where deer need to be encouraged to move to another less sensitive area.
Feral deer can be effectively deterred from a small property by trained guard dogs.
Chemical sterilisation treatments have not successfully been seen to reduce feral deer population anywhere in Australia. The sterilisation process is expensive, labour intensive and does not reduce the immediate environmental, economic and social impacts the feral deer are posing on the landscape.
A Standard operating procedure is available for the ground shooting of feral deer. NSW Department for Primary Industries are developing additional Standard Operating Procedures and Codes of Practice to standardise the way deer control methods are applied to reduce or prevent animal welfare issues. These consider the timing, location and coordination of control, type of calibre of firearm and ammunition and skill of operators.
Read more about humane ways of culling pest animals.
How many feral deer need to be removed each year to reduce impacts in the area?
The most efficient and cost-effective way to control impacts of deer, or to stop them establishing, is when they are in low numbers. If there are small numbers in an isolated area, then eradication is possible. As the numbers of feral deer increase and they become more widespread, it costs more to manage and contain them in the long term.
Modelling data by Hone et al (2010) estimated that in good conditions the following proportions of the deer population (in the local area) need to be removed to stop population growth:
34% Fallow deer
40% Sambar deer
Hone. J, Duncan. R and Forsyth. D (2010) Estimates of maximum annual population growth rates of mammals and their application in wildlife management. Journal of Applied Ecology, 47, 507-514
This graph shows the potential growth of a fallow deer population in good conditions, with and without culling of 34% each year.
*Assumptions of the graphed model
50% population is female (at beginning)
80% of the females are adult
80% of the adult females reproduce 1 fawn
50% fawns each year are female
cull rate is 34% and natural 6% attrition
assume 50% female and 50% males culled
State Legislation for deer management across Australia
Each of Australia’s states and territories has their own legislation for managing pest animals, including deer.