A Growing Problem
Deer were brought to Australia for hunting and farming in the 1800s.
Over time feral populations established, but until recently their impacts were not widely recognised.
Today the extensive population growth poses threats to Australia’s primary production, environment and communities.
The species that established include red, fallow, chital, sambar, rusa and hog deer. In the 1990s, numbers of feral deer increased following a decline in the venison and velvet market, and the subsequent escape or release of farmed deer.
Feral deer populations are now large and well established in many parts of Australia, and their impacts on the environment, primary production and communities are getting worse.
Deer are in all states and territories of Australia, but they are in largest numbers in the eastern parts of Victoria and New South Wales, where they are spreading quickly. For example, in New South Wales, the six species of feral deer now inhabit 22 per cent of the State, where their distribution has spread by 35 per cent since 2016. Populations are smaller and more isolated to the west of the Great Divide and in other states and territories, but even some of these populations number in the tens of thousands.
2022 Feral Deer Distribution
Distribution of feral deer in Australia
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- A map showing the indicative distribution of feral deer, compared to the location of internationally and nationally significant wetland and heritage sites vulnerable to the impacts of feral deer.
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- A map showing the indicative distributions of threatened species (green) and ecological communities (yellow) that are vulnerable to damage by feral deer according to current literature. The light green area across southern Australia comes from the modelled distribution of malleefowl alone.
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- A map depicting where feral deer distributions overlap with, or are in the vicinity of regenerating bushland that was recently affected by bushfires in 2019-2020.
** Refer to notes for disclaimer
Costing land managers an average of $2,627 per year per property for feral deer control activities (ABARES, 2019)
Upsetting the balance of our native habitats, and hampering recovery of bushfire-affected bush
Developing the plan to tackle the feral deer issue across all of Australia
We’re stronger together. Play your part in our country's recovery.
Predictive models, based on habitat requirements of feral deer, indicate that one or more deer species could potentially spread to most parts of Australia.
Our challenge is to stop the current spread of feral deer.
Where it could go...
Potential distribution of deer (six species), estimated using the Climatch algorithm. Dark red shows the areas where the habitat and climate is most suitable for one or more species of deer. Green shows areas less suitable for deer.
Some farmland regions in NSW have
30 feral deer per km2
Such densities require expensive helicopter culls to get them under control.
The number of feral deer in Australia are poorly understood, but there could be between one and two million feral deer.
In the absence of culling and when conditions are favourable, populations of feral deer can increase by between 34 and 50 per cent per year. Without culling, a small herd of 30 feral deer can grow to 500 in 10 years.
Intensive culling has the capacity to moderate deer population growth. For example, in Tasmania, recreational hunting has limited the average population growth rate to about 5 per cent per year; a rate that sees the population double every 15 years.
Our other challenge in protecting Australia’s valuable assets is to stop existing deer populations from getting out of control, to protect our most valued assets. Because feral deer readily move across property boundaries, neighbours and communities need to work together across whole landscapes to pool and coordinate efforts. In order to counter natural population growth, communities should use best practice control measures to reduce feral deer populations by at least 35 each year.
Listen to the podcast
Towards a Feral Free Future : Oh deer! We have a problem here. Produced by the Centre for Invasive Species Solutions.
At least 35% of feral deer need to be removed from a local population, each year, to have on-going reductions in impacts.
Impacts to Agriculture
Feral deer cause severe economic, environmental and social impacts. Economic impacts for the agricultural sector include their consumption of and damage to crops, pastures, and saplings. They also flatten fences and damage infrastructure. Additionally, feral deer pose a biosecurity risk through the transmission of diseases and parasites to livestock. Increasingly, they are also a pest of backyard gardens, particularly in peri-urban areas.
Fast Fact: How much of my pasture does a deer eat?
A fallow deer eats 1.8 to 2.3 times as much as a sheep (Dry Sheep Equivalent). A red or rusa deer eats 2.8 to 3.6 times as much as a sheep.
Fast Fact:
Fallow deer in Tasmania cost the state’s agricultural industry at least
$10 million annually.
Biosecurity Risk
Feral deer pose a biosecurity risk through the transmission of diseases and parasites to livestock. Biosecurity risks include Brucellosis, Bovine Tuberculosis, Johne’s disease, Cattle tick, Leptospirosis and Foot and Mouth Disease (not currently in Australia).
In other countries, Foot and Mouth Disease outbreaks result in export bans on livestock products, and low market prices. Containing such outbreaks in feral deer populations is difficult and expensive.
Fast Fact:
A small Foot and Mouth Disease outbreak, controlled in 3 months, could cost Australia around $7.1 billion, while a large 12-month outbreak would cost $16 billion.
Impacts to the Environment
Feral deer threaten biodiversity and ecosystems including in National Parks and Reserves and heritage listed rainforest areas.
Deer have profound impact on the composition of plant species in a native environment. They browse on young trees and foliage, damage or destroy mature trees through ringbarking and can spread weeds. In addition as hooved animals they impact vegetation through trampling and pugging waterways.
By changing the structure and composition of vegetation other levels of the ecosystem are impacted, for example native flora.
In New South Wales, environmental impacts of deer are listed as a key threatening process under the State’s Threatened Species Act 1995.
Two sisters discuss impacts of feral deer: A chat between two sisters in two states, one living with the effects of an established feral deer population, the other curious as to how the coming migration of deer into the Border Ranges NSW, will affect her rural lifestyle (they’re here already, actually, so listen up. Yes, you!).
Feral deer impacts are now occurring in areas where they are native. Watch the below video to learn about how the reduction of feral deer impacts in Yellowstone National Park not just transformed the ecosystem but also its physical geography.
Fast Fact:
In Victoria, Sambar are listed as a potentially threatening process to native vegetation, including threatened Alpine Sphagnum Bog communities. The Victorian Deer Control Strategy 2021 suggests that over a thousand native plant and animal species would benefit from deer control efforts across the state.
“The only way that Parks Victoria and Friends of Helmeted Honeyeater can create new habitat for the helmeted honeyeater is to surround that vegetation with expensive deer exclusion fencing”
– Gaye Gadsden.
“In order to be Wold Heritage you have to maintain the natural and cultural values for which you are listed and feral deer put that at risk because what they’re doing is undermining some of the specific criteria for which World Heritage was granted.”
– Christine Milne – Ambassador for Invasive Species Council
Impacts to bushfire affected regions
Feral deer significantly impact bushfire recovery.
Firstly, feral deer directly affect success of regeneration. A post-bushfire environment is vulnerable to trampling by hard hooved animals like feral deer. Additionally, deer graze on saplings which emerge as a natural course of bushfire regeneration, preventing their establishment and ringbark remaining trees.
Secondly, feral deer populations increase in size and in spread post-bushfires, placing further pressure on the recovering land. For example, after the bushfires in Royal National Park in 1994, local deer densities rose from <500 to 2500 in 1999. Increased densities of feral deer can be supported due to the high level of nutritious saplings. Spread is facilitated by necessity to move into unburnt areas, and increased access to land that was previously impenetrable.
A map depicting where feral deer distributions overlap with, or are in the vicinity of regenerating bushland that was recently affected by bushfires in 2019-2020.
In addition to direct impact to natural bushfire recovery, feral deer have significant impact on regeneration attempts
“There is absolutely no point being involved in bushcare recovery if you can’t also protect the forest from the deer” – Kieran Tapsell
To reduce the pressure of herbivory on restored forests, protective guards for individual plants or exclusion fences around plots of planted seedlings are frequently used. The requirement for deer-proof equipment increases the cost and time required for regeneration attempts.
Impacts to road and human safety
Social impacts of feral deer include vehicle collisions and fears of them. Additionally, deer attract poachers, who sometimes trespass, use firearms illegally, cut fences and frighten residents. Land managers struggling to control feral deer report declines in their wellbeing and problematic relationships with neighbours who do not control their feral deer.
In vegetation impact studies, most thrashing of vegetation by feral deer occurs along roadside verges. These findings suggest deer use roads to move through their range and thrashed vegetation advertises their presence to other males in the area.
Fast Fact:
Deer are the 4th most commonly hit animal in Australia, and the number of collisions is increasing each year.
Note. Figures 6 and 7 were produced by the Commonwealth in 2023. While every effort has been made to ensure accuracy and completeness, no guarantee is given, nor responsibility taken by the Commonwealth for errors or omissions and the Commonwealth does not accept responsibility in respect of any information or advice given in relation to, or as consequence of, anything containing herein. Figure 6 and 7 under task reference NRM2023/14. Figure 9 was produced by the Commonwealth under task reference NRM2022/31. These references are to aid version control and departmental task management. Figures 6 and 7 were produced under task reference NRM2023/14. Figure 9 was produced by the Commonwealth under task reference NRM2022/31. These references are to aid version control and departmental task management.
Note Figure 9. This map of deer distribution (and grey areas in figures 5,6,7) is indicative only. The most recent available sources of state and territory-level data (in 2022) have been compiled by the Commonwealth to produce a national map. For this reason, the national occurrence map is not consistent across jurisdictions in currency, resolution, or methodology and definitions of occurrence employed by each jurisdiction. This map should therefore be considered as a communication and engagement tool, rather than as a basis for further detailed analyses, and caution must be used in inferring the national distribution of feral deer using this map. Sources: NSW- Department of Primary Industries NSW 2020; Qld- Department of Agriculture and Fisheries Queensland 2018, 2014; Vic- Department of Environment, Land, Water and Planning Victoria 2020; Tas- Department of Natural Resources and Environment Tasmania 2021; SA- Department of Primary Industries and Regions South Australia 2021; NT and WA- National Land & Water Resources Audit 2008. The Australian Google Earth Engine Burnt Area Map (orange layer in Figure 9) was developed by New South Wales Department of Planning, Industry and Environment.