Control programs to reduce impacts of feral deer must be done as humanely as possible, at sufficient intensities and across most properties where the deer roam. The most effective way to achieve this is for neighbours to coordinate a control program together.
Land managers do not have many control tools with which to control feral deer; they can either be shot from helicopters or from the ground. The efficiency of shooting can be increased through the assistance of traps, spotlights, thermal imaging equipment and noise suppressors (pending local laws). They can also be kept out by fences.
Ground shooting can be an effective tool for reducing small to moderate numbers of feral deer, and is 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 or night vision or by thermal scopes or drones, or with detection dogs. Suppressors (where permitted by State authorities) reduce the noise of ground shooting, which enables more feral deer to be shot in an area at one time, and they also reduce disturbance for residents.
Ground shooting for controlling feral deer is done by professional shooters, commercial harvesters, or by land managers, their staff and/or volunteer shooters All must have appropriate firearms, licences and property access approvals as per State regulations. Standard operating procedures and the National Animal Welfare Codes of Practice guide safety and welfare outcomes.
Recreational shooting where the motivation is purely to source an animal for meat or trophy will generally not remove sufficient feral deer to reduce impacts or meet control program goals in many parts of Australia.
Watch a video introducing Ground shooting of feral deer:
Aerial 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.
Watch a video introducing Aerial shooting of feral 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. 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 about 2 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.
Watch a video introducing Exclusion fencing of feral deer:
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.
Commercial harvesters are required to follow safe operation protocols, meet high levels of animal welfare (e.g. National Animal Welfare Codes of Practice), and farm practices, including biosecurity protocols.
Game meat processors across Australia can refer harvesters to land managers.
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.
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 other 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.
FeralScan is a free resource for landholders and community groups to record pest animal sightings, impact and control activities. FeralScan can be found online and the phone app can be downloaded for free.
Recording feral deer data such as sightings and impacts helps develop knowledge of deer locations and help guide strategic control. DeerScan is user friendly and allows neighbours to work together in a coordinated approach to increase knowledge about deer in their area.
Centre for Invasive Species Solutions (CISS) is a national collaborative research, development and extension organisation, tackling the ongoing threat from invasive species. CISS brings together government, industry and research partners to develop coordinated and collaborative RD&E portfolios and innovation pipelines that meet national invasive species challenges.
CISS collaborates with several partner led research projects which aim to benefit deer control programs:
Development of feral deer aggregator control tool.