Monitoring deer – the what, the where and the how (many).

Australia doesn’t have a lot of data on deer. Until now we haven’t really needed it. Deer numbers were small. They posed no threat to primary producers, no threat to the environment and the native animals who live there, no threat on our roads.

But in the last few years this has changed. Their numbers have increased exponentially and now we are beginning to see just how destructive they can be.

So now the scientific community are playing catchup: how many deer are there? What species are there and where are they? How do they move and behave in the Australian landscape? What do they eat, what weeds do they distribute, what effect are they having on our waterways and peatlands, what diseases do they carry, and pass on, … there is a long list of unknowns, few knowns.

Government agency and environment groups are becoming increasingly active in their efforts to gain some of this data. Below is a precis of some of the more common methods being used:

Animal surveys
Camera-trap surveys
What are they

Camera traps are motion and/or infrared sensitive cameras which are strategically placed and left in situ to take images of animal movement in their vicinity. They are usually left in place for periods of weeks, after which their images are downloaded and visually assessed for species types, numbers and locations.
Camera-trap surveys will usually be trying to ascertain one of three types of information:

1.Relative abundance

• Easy, relatively cheap
  
• Checks for population change over time ie long-term studies
• Prone to error and miscalculation
  

2. Occupancy

• More complex
• For emerging populations
• Calculates % of area inhabited, not numbers of deer
  

3. Density

• Highly complex, much more expensive, requiring complex statistical analysis
• Measures the number of deer in a given area ie stocking rate
• Good for determining the impact of control measures
• Better suited for smaller sized sites
  

Advantages

• very effective
• easily repeatable
• can use citizen science
• cheap in the long term, especially if citizen science is engaged
• good for smaller populations and denser forests
  

Disadvantages

• need good cameras (>$300 each) and a lot of them, sometimes 60 or more
• initially expensive, especially for larger areas
• visually processing images is very time consuming and can exhaust volunteer enthusiasm
  

Future

• visual recognition software almost at the stage where it can identify individual species which will aid in processing images. This will significantly reduce cost/time & volunteer fatigue
• within camera IT becoming available which can communicate when species are present remotely and either send an alert or close an enclosure gate etc
  

Aerial surveys
What are they

Aerial surveys are done either by helicopter or drone. Helicopter surveys can be either manned (ie. visual only), use infrared cameras or both infrared & visual; drone surveys use infrared cameras only. Drones can be either the vertical or horizontal launch types.
Surveys are normally done at dawn or dusk when the deer are more active and come out of the bush. This also allows better differentiation between the heat signature of the animals and the cooler background. Sometimes this is not possible in more populated areas due to concerns of disturbance, and surveys may need to be extended into the mornings and afternoons.

The data gathered is then assessed and mapped to give an indication of the location and density of the deer population. This is increasingly being aided by species recognition software.

Aerial surveys are becoming increasingly popular as their costs decrease and the technology improves.

Advantages

Helicopter over drone:

• more economic over larger areas
• can be manned and therefore allow visual comparison to the IR camera
• better over hilly country
• tend to disturb animals and cause them to move, allowing greater chance of seeing them through denser canopy
• cover greater area in a shorter time
  

Drone over a helicopter:

• they can fly lower and closer to houses; good for more populated areas
• cause less disturbance to land owners
  

In general, aerial surveys are of greatest benefit over large areas, with large numbers of animals and with open vegetation.

Disadvantages

• drones, by regulation, must fly within line of sight of the operator. This means multiple sites will be required in hilly areas, meaning one survey with helicopter the survey may take several days of work with a drone. This can increase costs markedly
• helicopters especially can be noisy and greater care must be taken around built-up areas
• not reliable yet in differentiating deer species
• cost – neither are cheap, though, because less working hours are required in set-up and monitoring, they may well prove competitive over time. At the moment the costs of helicopters and drones is similar, though very dependant on topography, tree cover and residential density. Drones are becoming increasingly competitive though due to improving technology
  

Future

• IR camera technology is continually improving, resulting in better definition & image refresh rates, allowing better species recognition and faster flying speeds
• Improvement in drone technology is allowing better control & the transport of heavier equipment over longer distances.
• Drones are getting cheaper, decreasing overall costs
• Species recognition software is continually improving, allowing better identification and separation of species
  

Direct visual surveys
What are they

Just what it says – simply people observing deer in their own surrounds, logging the data, including date, time & location and other observations. It can be with or without binoculars or, if after dark, with a thermal imaging scope.
With proper scientific input, this data can be quite valuable. Not all surveys require advanced technology nor large amounts of expertise. This makes visual surveys a good mechanism for engaging the community.

The DeerScan app is an example of a direct survey technique, where members of the community can use the app to record sightings of deer. These records can include other signs of deer as well, including finding deer scat, wallows, tree rubbings or even hearing deer. CDMC are registered as a Group within DeerScan. For more information on DeerScan and how you might be able to help us monitor deer, read the article on DeerScan under Get Involved on our website.

Some other methods of recording animal sightings, including deer, is the Atlas of Living Australia or iNaturalist, which are available free to all.
Radio trackingWhat are theyThis requires the placing of a radio tracking device on each animal. The device emits a signal which can then be used to locate the animal. Some of these need to be tracked using a hand held aerial, whereas others can be picked up and located by satellite.

Advantages

• Satellite-linked devices can give information about animal movements to gain a better knowledge about the movement of deer through the district and deer behaviour – where they eat, where they rest, deer social interaction
• Much of this can be done from the comfort of a desk, with a daily location map on your computer screen
  

Disadvantages

• Very expensive: the devices are not cheap and putting them on the deer is very expensive, requiring capture & sedation of the deer
• The devices may influence deer behaviour subsequent to the trapping
• Animal welfare issues – deer are easily stressed and can damage themselves when being trapped
  

Radio tracking would be a wonderful tool to add to the deer knowledge base, as there is scarce information about the behaviour of deer in our landscape. Understanding this would be a wonderful help in planning for better techniques in controlling deer. Unfortunately it is extremely expensive and due to animal ethics reasons are usually conducted by a university or other scientific organisation.

Faecal pellet surveys
What are they

Not the most romantic of surveys, but highly effective. In this technique, regular counts of faecal pellets are conducted at nominated sites over a regular timeframe. This is then compared over time to see if the counts decrease or increase.

Advantages

• Very cheap
• Little expertise required
• Good for monitoring changes of deer population over time
• Good use of citizen science
  

Disadvantages

• Not a good indicator of deer numbers
• Not reliable in differentiating deer species
• Need scientific help to set the study up
  

Note: The use of DNA analysis of faecal samples can also be very valuable in identifying species, population sizes (variation found between samples) and the origins and movement of deer over time. It is not commonly done due to expense and the expertise required.

Vegetation surveys
What are they

There are three major categories of these:

• Monitoring which species are present and in what quantities
• Monitoring the regrowth rates of species – ie How many saplings are surviving? How many new plants are coming through?
• Monitoring the damage being done to existing vegetation
  

Advantages

• They give some of the most important information ie exactly how much damage is being done. What are happening to the existing species? Is biodiversity being affected?
• Very accurate and repeatable studies
• Give a good indication over time of the state of the environment
• Give a good indication of the impact of deer
• Are very useful when monitoring the environmental effects of an animal reduction program
• Give useful parameters when applying for government grant monies to control deer, where you can actually demonstrate the environmental value of reducing deer numbers
  

Disadvantages

• Vegetation surveys are quite technical and require a lot of expertise both in setting them up and assessing them
• Not so good for citizen science due to expertise required
• Expensive
• Take years to get meaningful results
  

Other

There are several other areas of measuring deer impact, such as loss of farm income, monitoring costs of deer mitigation, costs of deer vehicle collisions. Too many to cover in this article.

If you have further information in this area, or questions relating to any of the above, we would love to hear from you. Please email us at info@cardiniadeer.org.au

Coming soon...

Why has the Victorian government persisted with classing deer as “protected” ?

Commonwealth and state governments recognise that deer are a key threatening process in
the landscape; they are having a major financial impact on farming communities, are
threatening biodiversity and are an increasing danger on our roads. Deer are not native.

Victoria is the last remaining mainland state to keep listed deer as a protected species. All the others have declared them as a pest species, including now NSW, who changed their status in 2019. In Victoria, there is no official stated justification for their protected status. However, following discussions between government officials and the Cardinia Deer Management Coalition (CDMC), the following reasons seem to prevail:

1. Changing the status to pest animal will reduce the government’s ability to regulate the
manner in which deer are hunted. For example, hunters may not use the appropriate
calibre of weapon or weight of bullet, resulting in the inhumane killing or injury of deer.
They are also concerned about the use of spotlighting in relation to the hunter’s code of
a “fair chase.”

2. Changing the status to feral animal may cause a financial and management burden to
farmers. This is because landowners would then be compelled to control deer on their
property. It would also further compel government agencies to control deer on public
land.

3. Unregulated hunting may encourage “rogue” hunters to target deer, especially in the
state parks and private land. This could become a public safety issue as less skilled and
less ethical hunters become more active.

4. Changing the status to pest species is not required anymore because of recent changes
to legislation removing the protected status of deer on private land if deer are causing
harm or damage. This means landowners can control deer (except for hog deer) on
private land without a permit.

The CDMC are strongly of the view that deer should be declared as a pest species in Victoria, as they already are in Queensland, South Australia, West Australia, The ACT and the Northern Territory. This would bring them into line with the other states and reflect in words and law the recognised seriousness of the problem of deer in the Australian landscape.

In giving our reasons, we will address each of the four topics listed above:

1. "Reducing the government’s ability to regulate the manner in which deer are hunted."

• “Fair chase” does not apply when deer are controlled (private land), only when they are hunted (public land.) There are two ethical standards being applied depending on which side of the fence a deer is standing. This regulation specifies the calibre of rifle, type of bullet or use of spotlights when hunting deer.
• The use of the term “fair chase” only has meaning to the hunter, not to the deer. The most important concern should be that hunting and controlling deer should be humane across all land tenures. Regulations can and should be changed to reflect this.
• Stringent laws should be in place for the humane treatment of all animals, including when controlling them, even the ones we don’t like. Deer are not special in this sense; control of all pest species should be humane, whether they are foxes or cats, camels or cane toads.

        
2.  "A financial and management burden to farmers …", "compelled to control deer … "

• Firstly, this is not just about farmers, but about owners of all the land where deer can feed and take refuge, both private and public.
• Deer are already a financial burden to farmers. With protected status, your neighbour could be feeding and nurturing on their land the same deer that are jumping the fence and destroying your crops/vineyard/orchard. Legally. It is not fair that those suffering the most loss should shoulder the burden of controlling the deer that are being nourished across the whole landscape, including public lands.
• Farmers already have pest animals on their farms which they are already required by law to control, such as rabbits, foxes, pigs and goats. These animals have been declared as pests for the same reasons deer are of concern.
• It is right and necessary to require control of an introduced feral species which threaten our natural heritage and livelihoods.
• Government agencies should also be compelled to control deer as a pest species, especially in areas where they are threat to farm incomes. Where public areas are to be set aside for recreational hunting, the effects of this on surrounding landowners need to be assessed and mitigated where necessary, as a government expense.

3. "Unregulated hunting may encourage illegal hunters …"

• Illegal and “rogue” hunting has always been a problem and always will be a problem. Farmers and landowners already experience on a regular basis the sight of a deer shot near the roadside on their land with its head cut off.
• The best way to reduce this with respect to deer hunting is -
  • Firstly to encourage and resource the stringent policing of the current regulations and enact and apply proper penalty legislation.
  • Secondly ensuring proper hunter education is available.
  • And thirdly, to reduce deer numbers, especially in urban, periurban and farming areas.

4. "Changing the status to pest species is not required anymore because of recent changes
to legislation."

• We acknowledge recent changes of legislation make it easier for landowners to control deer on their own property, however …
• An individual landowner cannot control a problem that is not limited to their own property. Our neighbours must all (private and public) play their part.
• Calling a feral species a pest animal sends a strong message to the whole community: these animals are not benevolent bystanders, they are destroying our environment, affecting livelihoods and community amenity and are a danger on our roads. The message must get out and it is the government’s role to lead this.
• All other mainland states have grappled with this issue and declared deer a pest species
• It is fundamentally wrong that a damaging invasive species should not be recognised as such in law.

The impact of deer on private property and costs to our farming community are escalating rapidly.
 
When the first community meeting to discuss the issue of deer in our catchment was organised by the Upper Beaconsfield Conservation Group, environmental damage was at the forefront of their thoughts and concerns. It quickly became apparent during the Q and A open forum session, the issue of deer encroaching on private land was possibly THE big issue for most people there. 
Boundary fences were no barrier to deer, who can leap over a two metre fence from a standing start. Landowners had no control over the deer and the damage being caused in a single night could be devastating.
We have had correspondence from private landowners like:
“I have read the interesting article in the Upper Beaconsfield Village Bell, in reference to the feral deer problem.
My property is situated on Wellington Road, and we are visited daily by a herd of deer, which is causing damage to paddocks, and garden!
I am actually at my wits end as to how this constant invasion will ever cease.”
One landowner’s reply to a survey asking farmers to quantify the value of damage to their farming enterprises was eye-opening:
“Our biggest impact is on our fruit trees.
Trees that are 6-30 years old and 6 m tall can be badly damaged in one night.
It is very disheartening, expensive to replace (cost of new trees, and labour and machinery hire to removal the old trees  and putting in a new ones) and then there is the economic cost of the fruit lost each year until the new tree is fully mature (15 years).”
All up the farmer put a conservative estimate of replacement cost & lost income per tree before reaching maturity of $1610. As well as this there is the cost of erecting 2m high deer proof fencing around the property, which regularly need repairing due to damage caused by deer.
Among the hardest hit are the Landcare “communities”. Revegetation works they have been carrying out for decades are being hard hit as the usual tree guards offer no protection against deer. Reports of planting survival rates dropping from the usual 95% down to 30% and worse are now heard. A Tonimbuk farmer was nearly in tears at a recent meeting as he described the devastation wreaked on his revegetation works he’d carried out since the Ash Wednesday fires of ’83 by deer.
There are some landowners who “don’t mind bambi at the bottom of the paddock.” Deer are a beautiful animal and can’t be blamed for being transported to Australia. And they don’t “intend” to do harm. But harm happens, and bambi doesn’t stay in that paddock, but goes into the next, and the garden next door, and the orchard over the road.
(For a transcript of a letter from one of our members written in response to the DEWLP draft Deer Management Strategy, click here.)

Due to their sheer size, speed & escalating numbers, deer are now a major danger on our local roads.

In 2015 deer overtook cattle as the fourth most common animal collision reported to the RACV in Victoria.

Deer are now commonly seen beside and crossing the roads in our area, and local panel beaters have noted an increasing number of deer related repairs.
Deer are a serious concern to motorists due to their absolute lack of road sense and to their size and speed. A fully grown sambar can weigh over 400kg and, with a high centre of gravity, this can be a lethal combination. This means that in a frontal collision at speed, the body of the deer will likely come over the bonnet, through the windscreen and into the cabin of the car. Even the smaller fallow deer at up to 200kg would be a serious threat. Australia has already had its first fatal deer accident, although fatal accidents are well known in North America.
Some general advice:

• deer are more active between dusk and midnight, and at dawn, so either avoid driving at these times or slow down
• the worst time of year is in the autumn when deer are mating and so are more likely to be moving between areas looking for a mate
• motorcycle riders are particularly at risk due to the sheer size of the animals
• drivers of the newer hybrid and electric cars are also at increased risk: these cars are much quieter, so deer have less warning to move away from the road.

Deer-vehicle collisions have been an ongoing issue in Europe and the USA for decades, where a number of methods are being used or trialled to overcome this problem, from exclusion fencing to flashing lights alerting the presence of deer on the road and more. Some councils in Victoria have now installed deer warning signs in addition to the usual kangaroo, wombat and emu signs. In the end, along with trying to keep deer numbers down, a combination of these methods may be required to minimise the impact of deer on our roads.

Deer are not native to Australia. They have only been here since about the 1860s. Along with the likes of rabbits, foxes, sparrows, blackbirds and many other species, they were originally introduced into the environment by homesick English settlers, both for sentimental reasons and hunting enjoyment. In the 1970s and ‘80s, deer farming became popular as a new way to generate farm income. As with many boom industries, the bust soon followed and many farmers simply opened their gates and let the deer out.
It seemed for a while that deer were quite benevolent in our landscape: cute little bambis standing by the road verge, quietly nibbling away on the grass with no adverse effects, effortlessly leaping over the fence as we drove by.
Unfortunately, it was not to remain so. We are not yet sure why, but things have suddenly changed over the last two decades. Roadside sightings are no longer rare nor special and we have now had our first deer related fatalities on the nation’s roads. Farmers now find themselves competing with deer on a daily basis. And the Australian environment, especially in the creek valleys, is being trashed.
Deer are known as “ecosystem engineers”. These are organisms that create, significantly modify, maintain or destroy a habitat. Ecosystem engineers can have a large impact on the species richness and landscape-level heterogeneity, especially when such an organism arrives in a new area. This is happening in the Cardinia valley right now, to such an extent that both Melbourne Water and Parks Vic have both started to take serious action to limit deer numbers to preserve the natural environment.
Deer damage the environment in a number of ways. Being browsers, they eat a lot of our native shrubs, such as pomaderris and muttonwood, along with the emerging seedlings of the trees, reducing food sources and nesting sites for native wildlife. When the deer population reaches a certain size this prevents regrowth of the various forest species. They also rub their antlers on the trees, effectively ringbarking and killing them. Unlike kangaroos and wallabies, they are cloven hooved, which means they cause impaction of the ground wherever they walk, leaving hard trails through the bush. In the swampy areas they leave pug marks in the ground or worse, create mud wallows, damage the creek banks, increasing siltation and water turbidity, affecting the fresh water crayfish and the platypus that live on them.
Feral deer have been described as “the most serious invasive problem” in NSW and the ACT. The situation is arguably worse in Victoria. Our environment, still struggling to cope with the impact of feral cats and foxes, and feeling the early effects of global warming, can not afford another threat to its existence.