Tasmania's Largest Mammal is Disappearing Before Our Eyes...
- Jessica O'Connor
- Oct 23
- 8 min read
Updated: Oct 24
Why is nothing being done to stop a looming extinction?
I'm not a mathematician or a statistician, but something is very wrong and it needs to be known:
At first glance, it seems that there would have to be some sort of mistake. After what happened to the infamous Thylacine (Tasmanian Tiger) and the lesser known Tasmanian Emu - both heavily persecuted, devastated by habitat destruction and ultimately hunted to extinction -a lesson should have been learnt.
Most people go about their lives assuming that the lesson was learnt and that there are checks and balances in place to prevent future extinctions. Conservation programs, population counts, species protections and environmental legislation are all measures put in place by State and Federal Governments to monitor, prevent and circumvent extinction events. We've seen that there have been concerted efforts made to preserve certain at-risk species such as the Tasmanian Devil and the Orange Bellied Parrot and we are generally under the impression that if there was an extinction looming it would be noticed and monitored, and measures would be put in place to mitigate it before it got to the point of crisis. Unfortunately, we are mislead in this assumption.
As you read this, the same persecution, habitat destruction and hunting to extinction that sealed the fate of the Thylacine and the Tasmanian Emu is playing out again, this time to Tasmania's largest mammal - the Forester kangaroo; an intelligent, peaceful and gentle herbivore that is only found in Tasmania and falsely targeted as a nuisance and an agricultural pest.
Completely unique, thanks to geographic isolation
The Forester kangaroo is a subspecies of the mainland’s eastern grey kangaroo. Like many native Tasmanian animals Forester kangaroos have unique physiological differences to their mainland cousins. These differences are a result of over 14,000 years of geographical isolation and evolution independent from mainland Australia.
Forester kangaroos vary from mainland eastern grey kangaroos by their smaller body size and heavier set build, differences in skull shape and structure, coat thickness, along with generally having a more flighty and nervous temperament.
Forester kangaroos have co-evolved with the land, vegetation and soil and are a keystone species, playing a major role in maintaining biodiversity and ecosystem health.
Even though they're slightly smaller than their mainland cousins, Forester kangaroos can still grow up to two meters tall and weigh up to 60kgs, making them Tasmania's largest mammal.
Forester kangaroos are primarily crepuscular (most active at dawn and dusk) and feed in open grasslands on grasses, forbs and herbs in the early hours of the morning and evening. They rest in shaded areas during the heat of the day, sometimes sunbathing in the open during the cooler months
Forester kangaroos are social animals and enjoy the company of one another, often grooming each other and laying side by side in large groups called mobs. Within the mob, smaller groups will break off and reform throughout the day. This is a unique social structure known as fission-fusion.
Research has shown that kangaroos can form long-term, close bonds with one another, similar to human relationships, and will grieve the loss of loved ones.
The ongoing consequences of colonisation
Forester kangaroos were once abundant in the northeast, the midlands, and the eastern part of the Central Plateau, but absent from the western part of the state. Their population has declined drastically since European settlement, where they were heavily hunted for human consumption and dog meat.
According to the Department of Climate Change, Energy, Environment and Water Tasmania, Forester kangaroos range and population has been reduced by at least 90% since white settlement.
Some efforts were made by the government to improve the situation in the 1950s after it was noted that Forester Kangaroos were close to extinction, and again in the 1970s, when population numbers were noted as low. However, there has never been a full recovery in terms of population or range.
Today, Forester kangaroos remain in several small pockets of the midlands and northeast of Tasmania, primarily inhabiting private land. Although their population has improved since its lowest point in the 1950s, issues such as habitat loss and degradation, legal and illegal culling, baiting, road deaths and climate change continue to threaten Forester kangaroo viability.
Put simply, the numbers just don't add up...
Even though Forester kangaroos are classified as ‘protected native wildlife’ under the Tasmanian Nature Conservation Act 2002, they are still legally culled under Property Protection Permits (PPPs).
According to The Humane Society International's "Licence to Kill" 2024 document, 6502 Forester Kangaroos were legally slaughtered in 2023 and 5238 were slaughtered in 2024 under Tasmanian PPPs
When paired with the current population data, it doesn't take a genius to realise that the Forester kangaroo is in real trouble.
In 2019, the Department of of Primary Industries, Parks, Water and Environment commissioned a baseline aerial survey to count fallow deer in the north east of Tasmania. Since this area was also the range of most of Tasmania's Forester kangaroos, an additional survey for Foresters was conducted simultaneously.
Two seperate aerial observation methods were used for each species, Multiple Covariate Distance Sampling (MCDS) was used for the Forester kangaroos and Mark Recapture Distance Sampling (MRDS) for the fallow deer.
The report and results for this survey can be found here.
After taking into account many variables, the official population estimate given for Forester kangaroos (using the MCDS method) was 30,327 individuals (+/-32% which is a huge variable).
At the end of the report it is mentioned that this estimate could have been as high as 61,516 if the MRDS method (the method used on the deer) had been used - confusing, right?
How low is low enough for concern?
Given the Forester kangaroo's fragmented and disappearing habitat, the 5,000+ PPP toll, and the assumed thousands of others who would have met their fate through illegal, accidental or natural means (and the possible variable of -32%,) a species population of 30,000 should be considered low - especially when compared with other native Tasmanian animals who've made it onto the Threatened Species List and have conservation programs aimed at boosting their numbers, such as the Tasmanian devil, whose population estimate is similar to the Forester Kangaroo at 25,000 individuals.
In 2005, the Forester kangaroo was assessed by the Threatened Species Scientific Committee (TSSC) for a place on the Threatened Species List, but was considered ineligible due to there being no evidence of population decline (because at that time there was no reliable population data, only anecdotal evidence).
The significance of an insignificance:
In 2024 a follow up population survey was commissioned by the Department of Natural Resources and Environment Tasmania using the same company and alleged identical survey methods for consistency. A slightly different, yet overlapping area, was surveyed. However, this was accounted for and explained in the results.
The report for this survey can be found here.
The interesting thing to note about this survey was that this time the MRDS method was used for both fallow deer and Forester kangaroos. This change in method is not noted in the survey report, and seems somewhat brushed over or mistaken for the same method (MCDS) used for Foresters in the 2019 survey.
In the report, the MCDS data from 2019 is (possibly by mistake?) represented as MRDS data and directly compared to the MRDS data gathered in the 2024 survey to show a statistical difference.
The report states that "The difference between the 2019 and 2024 population estimates in the overlapping area between the two surveys has shown an insignificant difference over the last 5 years from 24,948 +/- 24% forester kangaroos to 26,070 +/- 21% in 2024."
Had the unofficial MRDS population results from 2019 been correctly compared to the MRDS data gathered in 2024, the results would have shown a significant drop in population from 61,516 to 26,070, a reduction of 57.6%. This is an extremely significant and concerning drop in numbers that cannot and should not be ignored.
How was this issue not noted by anyone at Department of Natural Resources and Environment?
Moving on...
Possibly the most concerning part of the 2024 Population Survey Report was the addition of the "complicating issue" of species identification, which is also glazed over, but (in my opinion) corrupts the whole survey:
"An issue complicating the mark-recapture calculations for kangaroos in 2024 was that the observer counts sometimes disagreed on whether the macropods seen were forester kangaroos or Bennett’s wallabies. In the open, these species are easily told apart on aerial surveys by size, gait, behaviour,and tendency of foresters to gather in large groups, but they can be harder to distinguish when stationary or partly hidden by foliage. For the purposes of calculating the mark-recapture statistic for 2024, where assessing sightability of animals was more important than which kangaroo species was seen, the counts for both macropod species were pooled. The mark-recapture statistic therefore assumes that the probability of misclassifying a forester as a Bennett’s wallaby is equal to the probability of misclassifying a Bennett’s as a forester."
If I'm right, and I'm willing to be corrected here, this paragraph suggests that every animal sighted and classified as a Forester kangaroo during the survey was given an equal (50%) chance of actually being Bennett's wallaby.
This is said to have been accounted for statistically (by giving a 50/50 chance of misidentification), however, given the population estimate for Forester kangaroos was 1.381 per km2 in the 2019 Baseline Survey (using the MRDS method where this issue was not accounted for), and that the most recent population estimate for Bennett's wallabies in Tasmania, is 47.4 animals per km2 (Annual State-wide Spotlight Surveys Tasmania 2023/2024). It seems pretty obvious that the probability of a Forester kangaroo being counted as a Bennett's wallaby should have been calculated at a much higher percentage.
Ongoing consequences of a bad report
My concern is this: these are the stats that the government will be relying on to make future decisions about the management of Forester kangaroos in Tasmania. The information given in the 2024 Survey Report states that there has been no change in population and gives a misleading view of the harsh realities facing Forester kangaroos. Whether this is intentional or not is not known, however, it will have an impact and not a positive one.
The Tasmanian Government will use this information to continue to approve more PPPs, further devastating the Forester kangaroo population at rates that they simply cannot recover from.
Important measures that should be put in place to protect them will again be rejected, because the official paperwork states that their population numbers remained stable over the past 5 years.
The official paperwork is wrong.
Just like the thylacine and the Tasmanian emu, the Forester kangaroo is at extreme risk of being hunted to extinction. But we still have time to intervene.
I urge you to do your own research, look into it, make an informed opinion and if you don't like what you see, speak up. Write to a minister (link below), make some noise.
Our beautiful kangaroos cant speak for themselves and if things keep going the way they are, they'll be gone forever.
And from a first hand "boots on the ground" perspective:
Unfortunately, in our industry, we can often calculate population health based on the number of animals that we see coming into care, and this is what it looks like to me from a boots on the ground perspective:
More Tasmanian devil joeys and eastern barred bandicoot joeys (both on the threatened species list) come into care annually than Forester kangaroos joeys.
Statewide we see about 10-12 Forester kangaroo joeys come into care each year. These joeys mostly come to our centre (compared to the hundreds of Bennetts Wallaby joeys that come into care, this number seems disturbingly low)
We have never been overburdened by Forester kangaroo joeys and can sometimes go months without any coming into care at all.
We never get call outs for the rescue of adult kangaroos.
This is in stark comparison to other states, which have healthy kangaroo populations. States such as NSW and Victoria often see services and carers overburdened by kangaroo joeys and adult kangaroo rescues.
Do something - The Humane Society has a pre-filled form that you can send to the Environment and Agricultural Minister, urging them to protect our precious native wildlife. Please take the time to add your concerns abouit Tasmania's Forester kangaroo to this form before you send it off.
If you are a statistician, I would love to pick your brain about this issue... Please get in touch!
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