Dingoes found in New South Wales, but we’re killing them as ‘wild dogs’



One in four of nearly 800 animals genetically tested were pure dingo.
Michelle J Photography

Kylie M Cairns, UNSW; Brad Nesbitt, University of New England; Mathew Crowther, University of Sydney; Mike Letnic, UNSW, and Shawn Laffan, UNSW

There is a widespread belief dingoes are as good as extinct in New South Wales and nearly all dog-like animals in the wild are simply wild dogs. This belief is bolstered by legislation and policies in NSW, which have removed the word dingo and refer only to “wild dogs”.

But our research, recently published in the journal Conservation Genetics, challenges this assumption. We performed DNA ancestry testing, much like the ancestry tests available to people, on 783 wild canines killed as part of pest control measures in NSW.




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Roughly one in four of the animals we tested were pure dingoes, and most were genetically more than three-quarters dingo. Only 5 of the 783 animals we tested turned out to be feral domestic dogs with no dingo ancestry.

If it looks like a dingo, acts like a dingo and shares dingo genes… there’s a pretty good chance it’s a dingo.
Michelle J Photography, Author provided

Dingo hotspots

Studies carried out by the CSIRO in the 1980s and ‘90s examined the skulls of wild canines in southeastern Australia, and concluded they were largely hybrids of dingoes and dogs.

In NSW all wild dogs are classified as pest animals. Under the NSW Biosecurity Act 2015 all landholders have a duty to control wild dogs to minimise the risk of negative impacts on neighbouring land.

This policy requires all public and private landholders in NSW to display signs warning when poison baits have been laid to kill wild dogs.

But our DNA testing found three hotspots of high dingo ancestry within northeastern NSW: Washpool National Park; the coast north of Port Macquarie; and the Myall lakes region.

There were more pure dingoes in these areas. Despite these positive findings, dingo-dog hybridisation is still very prevalent in NSW. Three-quarters of wild animals carry some domestic dog ancestry.




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This is not entirely surprising. Domestic pet and working dogs have lived alongside dingoes for centuries. Widespread killing of dingoes also increases the risk of hybridisation because it breaks family groups apart, giving domestic dogs the opportunity to mate with dingoes. Small populations also have a higher risk of hybridisation.

1080 poison baits are affecting dingoes as well as feral dogs.
Mike Letnic

Hybridisation is generally considered detrimental to conservation because it alters the genome. In the case of dingoes, hybridisation is a problem because hybrids may be different to dingoes and “true” dingoes will eventually disappear.

While our results show dingoes still exist and their genes are predominate, their conservation will be greatly helped if we can prevent further interbreeding with domestic dogs.

Time to resurrect the dingo

Our study has important implications for both how we describe dingoes, and the future conservation of dingoes in NSW. Most of the animals labelled as wild dogs in NSW had predominantly dingo DNA, and fewer than 1% were actually feral dogs.

The term wild dog obfuscates the identity of wild animals whose genes are mostly dingo but sometimes carry dog genes. For all intents and purposes, these animals have dingo DNA, look like dingoes and behave like dingoes, and consequently should be labelled as dingoes rather than escaped pets gone wild.




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Hotspots with high dingo ancestry have significant conservation value and urgently need new management plans to ensure these pure dingo populations are protected from hybridisation. These populations could be protected by restricting the killing of dingoes in these areas and restricting access to domestic dogs on public land such as state forests.

Animals long thought to be wild dogs are actually predominantly dingoes.
Michelle J Photography, Author provided

Further ancestry testing should be conducted in more areas to determine whether there are other pockets of high dingo purity in NSW.

Undeniably, dingoes can negatively impact livestock producers, especially sheep farmers. Non-lethal strategies such as electric or exclusion fencing, and livestock guarding animals such as dogs, llamas and donkeys, may balance the need to conserve dingoes and protect vulnerable livestock.




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In some circumstances, dingoes can benefit farmers because they reduce numbers of native and feral herbivores like kangaroos, feral goats, rabbits and pigs, boosting pasture growth for livestock.

If lethal control is justified, then targeted strategies such as shooting and trapping may be more suitable in high dingo conservation areas rather than landscape-wide poison aerial baiting.

It is time to resurrect the dingo. The term dingo needs to come back into official language, and we need practical strategies for limiting dingo-dog hybridisation and protecting dingo hotspots.




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The Conversation


Kylie M Cairns, Research fellow, UNSW; Brad Nesbitt, Adjunct Research Fellow, University of New England; Mathew Crowther, Associate professor, University of Sydney; Mike Letnic, Professor, Centre for Ecosystem Science, UNSW, and Shawn Laffan, Associate professor, UNSW

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Eat your heart out: native water rats have worked out how to safely eat cane toads



Water rats in Western Australia are safely hunting cane toads.
Author provided

Marissa Parrott, University of Melbourne; Sean Doody, University of Newcastle, and Simon Clulow, Macquarie University

Australia’s water rats, or Rakali, are one of Australia’s beautiful but lesser-known native rodents. And these intelligent, semi-aquatic rats have revealed another talent: they are one of the only Australian mammals to safely eat toxic cane toads.

Our research, published today in Australian Mammalogy, found water rats in Western Australia adapted to hunt the highly poisonous toads less than two years after the toads moved into the rats’ territory.




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The rats, which can grow to over 1kg, are the only mammal found to specifically target large toads, neatly dissecting the toads to eat their hearts and livers while avoiding the poisonous skin and glands.

Water rats

Water rats are nocturnal and specially adapted to live in waterways, with webbed feet and soft water-resistant fur. Their fur is so impressive there was once a thriving water rat fur industry in Australia.

They can be found in lakes, rivers and estuaries, often living alongside people, in New South Wales, Queensland, Tasmania, South Australia, far north and southwest Western Australia, the Northern Territory, and Victoria, where they can even be seen along St Kilda Pier.

Water rats are also highly intelligent, as shown by their rapid adaptation to hunting and eating one of Australia’s most toxic introduced species – the invasive cane toad.

Cane toads were introduced to Australia in 1935 in an ill-fated attempt to control the cane beetle. They have spread across the north of the country at up to 60km per year, leaving devastation in their wake. Many native species, such as northern quolls, yellow-spotted monitors, and crocodiles, have suffered widespread declines, and in some cases local extinctions, as a result of eating cane toads.

The toads secrete a toxin in their parotoid glands (on the back, neck and shoulders) that can be fatal even in very small doses.

A cane toad at our field site in the Kimberley.
Marissa Parrott, Author provided

Eat your heart out

Cane toads arrived at our field site in the Kimberley, Western Australia, in 2011-12, leading to a crash in the populations of predators including numerous lizards and northern quolls.

However, in 2014 we found a creek dotted with the bodies of cane toads that had clearly been attacked. Every morning we discovered up to five new dead toads with small, near-identical incisions down their chest in just a five-metre stretch of creek. What was using almost surgical precision to attack these toads?

Post-mortem analysis showed that in larger toads the heart and liver had been removed, and the gall bladder (which contains toxic bile salts) neatly moved outside the chest cavity. In medium-sized toads, besides the removal of the heart and liver, one or both back legs had been stripped of their toxic skin and the muscle also eaten.

The finding intrigued us enough to dissect waterlogged and rotting toad bodies in 40℃ heat. Using remote infrared camera footage and analysis of the bites left on the muscle, we found our clever attacker – the native water rat!

A water rat caught on camera hunting for cane toads in the Kimberley.
Marissa Parrott, Author provided

What kind of toads are rats eating?

While there have been anecdotal reports of water rats eating toads in Queensland and the Northern Territory, there were no published reports of this in Western Australia, where the toad was a more recent arrival.

We also didn’t know whether rats could tolerate the toad toxins, or were targeting non-toxic parts of the body. And we wanted to find out whether the rats were targeting small (and less toxic) toads, as some other rodent species do, or were deliberately going after larger toads which are a better source of food.

During our study we captured and measured more than 1,800 cane toads in just 15 days in the vicinity of the water rats’ creek. The vast majority, 94%, were medium-sized; 3.5% were small (less than 4cm long); and just 2.5% were large (greater than 10cm long).

But despite medium toads being far more common, three quarters of the dead toads we found were large, and the remainder were medium. No small toad bodies were found or observed being attacked.

While some species, such as keelback snakes and several birds (including black and whistling kites, and crows) can eat cane toads, there has been less evidence of mammals hunting this new type of prey and living to tell the tale.

Some rodents can eat small juvenile toads, but no rodents have been documented specifically targeting large toads. In our case, water rats preferred to eat large toads, despite medium-sized toads outnumbering them by 27 to 1.

A water rat eating at Healesville Sanctuary.

We’re not sure whether water rats have very rapidly learned how to safely attack and eat cane toads, or if they are adapting a similar long-term hunting strategy that they may use to eat toxic native frogs.

Water rats are very well placed to pass on hunting strategies, as they care for their offspring for at least four weeks after they finish producing milk. This could help spread the knowledge of toad hunting across streams and creeks over time.




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While this behaviour seems to be confined to local populations, if these tactics spread, water rats may be able to suppress toad populations when they reach water bodies – another small line of defence against this toxic killer.The Conversation

Marissa Parrott, Reproductive Biologist, Wildlife Conservation & Science, Zoos Victoria, and Honorary Research Associate, BioSciences, University of Melbourne; Sean Doody, Conjoint Fellow, University of Newcastle, and Simon Clulow, MQ Research Fellow, Macquarie University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

How to know if we’re winning the war on Australia’s fire ant invasion, and what to do if we aren’t


Fire ants like these can give a nasty bite.
Shutterstock/SweetCrisis

Daniel Spring, University of Melbourne and Jonathan Keith, Monash University

More than A$400 million of government funding is being invested in the latest round of the fire ant program in the hope of eradicating the invasive pests by 2027.

But recent reports on the ABC suggest the invasion is spreading beyond containment lines in south-east Queensland, and there are delays in responding to public reports of new ant infestations.

The claims are denied by Graeme Dudgeon, the new general manager of Queensland Government’s National Red Imported Fire Ant Eradication Program.




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Fire ants are native to South America but nests were first discovered in Brisbane in 2001. It’s thought they arrived via shipping at the Port of Brisbane.

They’re regarded as one of the world’s worst invasive species and have a painful bite which is why the Queensland Government has been trying to wipe them out here.

Is eradication possible?

An independent review in 2016 found the fire ants were confined to a region of south east Queensland and said there was an opportunity to eradicate the pests.

But the latest debate raises the question of whether eradication is the best plan, or would further containing the spread of the fire ants be a more practicable solution?

To achieve its aim of eradicating the fire ant problem, the program needs to progressively shrink the invasion.

If the invasion is shrinking too slowly (or is expanding), eradication won’t be achieved by 2027. Without ongoing monitoring of the invasion’s size, the program might be failing without the general public knowing.

But knowing the fire ant invasion’s size isn’t easy because there isn’t enough funding to survey all locations that might have them.

Estimates of the invasion

Using records of past fire ant detections, we have demonstrated how to estimate the invasion’s size when only part of the managed area is surveyed.

Our inference of the boundary of the fire ant invasion in April 2015. The different coloured polygons correspond to different levels of credibility that the boundary contains the invasion, with the outermost boundary corresponding to the highest credibility. Small crosses represent sites where nests have been detected, with the most recent detections in red and the oldest in brown.
Nature/Authors provided, CC BY

If this approach to estimating the invasion boundary is applied each year during the current program, we could estimate whether the invasion is shrinking fast enough to be gone by 2027.

The importance of this issue demands a rigorous scientific analysis using transparent data and methods. Without this, anecdotal evidence that the current invasion is spreading is all we have to indicate whether eradication efforts are failing.

The size of the fire ant invasion should not only be measured in terms of the total area within its estimated boundary but also the density of nests within this area.

Eradication won’t be achieved if both the invasion boundary and the density within it are increasing. This straightforward test to determine whether the program is failing has not yet been applied.

But such a test could be done if updated records of the fire ant invasion are regularly made available to allow for periodic estimation of updated maps of the invasion.

Never give up

Even if eradication by 2027 is unlikely, this does not mean we should give up, provided future control efforts can contain the invasion at an affordable cost.

If the current program fails to eradicate the fire ants, it may still set the stage for effective long-term containment of the invasion.

A poor outcome will result if current management efforts are spread thinly over the infested area, reducing the density of nests but not eradicating them from any suburbs.

A better outcome would involve shrinking the infested area, that is, eradicating the ants from many or most suburbs, so that subsequent containment efforts can focus resources on a smaller area.

Is it still early enough in Australia to shrink the fire ant invasion to a manageably small area and thereby protect most homes and most of the environment for a long time? The required information to answer this question is not yet available.




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But if Queensland’s eradication program has substantially slowed the spread so far, this provides confidence that continuing the program could effectively suppress the invasion. If so, we need to estimate what it will cost to keep out fire ants from most homes and most of the environment for a long time.

It’s often claimed that removing the last 1% of invaders costs as much as removing the previous 99%. If the current program removes all ants from most areas by 2027, this may provide large benefits without the extra cost of finding the last few ants in all infested areas.

Even if we do eradicate fire ants this time, it’s almost certain they will be back because they can readily hitchhike rides on ships.

So if governments can keep fire ant numbers down through ongoing containment, a lot of people and a lot of native species will benefit.The Conversation

Daniel Spring, Research Fellow, School of Biosciences, University of Melbourne and Jonathan Keith, Associate Professor, School of Mathematical Sciences, Monash University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Making deer fair game for unlicensed hunting is the right step for New South Wales


The fate of deer carcasses is a crucial consideration in monitoring the success of future culling.
Emma Spencer, Author provided

Thomas Newsome, University of Sydney and Emma Spencer, University of Sydney

The New South Wales government last week revealed plans to ease shooting restrictions on feral deer. If the plans go ahead, deer will be stripped of their status as a game animal and will no longer be afforded protection under the state’s animal control laws.

This will mean that a game hunting licence would not be required for recreational, commercial and professional hunting of deer species. Restrictions on how and when deer can be hunted would also be lifted.

Feral deer will be treated the same as other pest animals in NSW, including red foxes, feral cats and rabbits.

Deer are already considered a pest

Last year the NSW government approved 11 regional pest animal plans, each of which declared deer as a priority pest species. Several hunting regulations have already been suspended to manage abundant deer populations, and in February 2019 the government announced a A$9 million deer control program described as the most extensive of its kind.




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Removing the game status of deer is the next logical step towards controlling existing deer numbers in NSW, and slowing their spread to new areas. Deer currently cover 17% of NSW, and this area has more than doubled since 2009.

Deer now cover 17% of NSW.
NSW Dept of Primary Industries

Without urgent and effective control, the deer population could spread throughout the entire state and beyond.

Effective control is needed to stop the spread of feral deer in Australia.
Emma Spencer

The impacts of deer

Feral deer remain one of Australia’s least studied introduced mammals. Yet the evidence shows they have a substantial impact on Australia’s ecosystems and agriculture.

Since 2005, grazing and environmental damage by feral deer has been listed as a key threatening process under NSW legislation. Deer are known to graze on threatened plant species, and also cause erosion and soil compaction. They damage pasture; destroy fences and contaminate water sources; harm trees via antler rubbing; rip up the ground during rutting season; and potentially contribute to the spread of livestock diseases.

Deer are a threat to humans too. The Illawarra region south of Sydney, a hotspot for deer activity, has seen one death and multiple serious injuries between 2003 and 2017 due to vehicle collisions with deer.

Deer can also carry pathogens that cause human disease such as Leptospirosis and Cryptosporidium.

Choosing the right control method

Ground-based shooting is the main way to manage deer in the urban fringes, regional areas and national parks. Unfortunately, coordinated ground shoots have only been effective for areas of less than 1,000 hectares, and there is no evidence that uncoordinated shooting by recreational hunters actually works to control deer on a widespread basis.

Aerial shooting can potentially be more successful over large tracts of land, but may not be a good option when tree cover is high and visibility is low. Poison baiting could help, although there is no method available to deliver baits safely, effectively and specifically to deer.

Irrespective of the control method, a coordinated approach is needed. We need a strategy that not only controls deer where damage is worst, but also prevents their spread to new areas. This will require NSW to work closely with the ACT and Victoria.

A red fox feeds on a culled feral deer.
Emma Spencer

Rigorous monitoring will also be vital. This is important to gauge success (how many deer were culled, and the ethics of shooting, trapping and baiting), and to determine whether the control efforts have unintended impacts on the environment, such as deer carcasses providing food for scavenging pests.




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Scavenging pests have been observed feeding on carcasses, but whether culling deer and other feral animals actually increases their abundance and impacts is unknown. Carcasses also provide a source of food for native scavengers such as eagles and ravens, and are integral to the structure and function of ecosystems.

The negative and positive impacts of deer culling on the broader ecosystem therefore needs consideration when developing and implementing monitoring plans. NSW can be the leader in this regard, starting from day one after removing the status of the deer as a game species.The Conversation

Thomas Newsome, Lecturer, University of Sydney and Emma Spencer, PhD candidate, University of Sydney

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Invasive species are Australia’s number-one extinction threat



Barking Owls are one of Australia’s 1,770 threatened or endangered species.
Navin/Flickr, CC BY-SA

Andy Sheppard, CSIRO and Linda Broadhurst, CSIRO

This week many people across the world stopped and stared as extreme headlines announced that one eighth of the world’s species – more than a million – are threatened with extinction.

According to the UN report from the Intergovernmental Science-Policy Platform for Biodiversity and Ecosystem Services (IPBES) which brought this situation to public attention, this startling number is a consequence of five direct causes: changes in land and sea use; direct exploitation of organisms; climate change; pollution; and invasion of alien species.




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It’s the last, invasive species, that threatens Australian animals and plants more than any other single factor.

Australia’s number one threat

Australia has an estimated 600,000 species of flora and fauna. Of these, about 100 are known to have gone extinct in the last 200 years. Currently, more than 1,770 are listed as threatened or endangered.

While the IPBES report ranks invasive alien species as the fifth most significant cause of global decline, in Australia it is a very different story.

Australia has the highest rate of vertebrate mammal extinction in the world, and invasive species are our number one threat.

Cats and foxes have driven 22 native mammals to extinction across central Australia and a new wave of decline – largely from cats – is taking place across northern Australia. Research has estimated 270 more threatened and endangered vertebrates are being affected by invasive species.

Introduced vertebrates have also driven several bird species on Norfolk Island extinct.

The effects of invasive species are getting worse

Although Australia’s stringent biosecurity measures have dramatically slowed the number of new invasive species arriving, those already here have continued to spread and their cumulative effect is growing.

Recent research highlights that 1,257 of Australia’s threatened and endangered species are directly affected by 207 invasive plants, 57 animals and three pathogens.

These affect our unique biodiversity, as well as the clean water and oxygen we breath – not to mention our cultural values.

When it comes to biodiversity, Australia is globally quite distinct. More than 70% of our species (69% of mammals, 46% of birds and 93% of reptiles) are found nowhere else on earth. A loss to Australia is therefore a loss to the world.

Some of these are ancient species like the Wollemi Pine, may have inhabited Australia for up to 200 million years, well before the dinosaurs.




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But invasive species are found in almost every part of Australia, from our rainforests, to our deserts, our farms, to our cities, our national parks and our rivers.

The cost to Australia

The cost of invasive species in Australia continue to grow with every new assessment.

The most recent estimates found the cost of controlling invasive species and economic losses to farmers in 2011-12 was A$13.6 billion. However this doesn’t include harm to biodiversity and the essential role native species play in our ecosystems, which – based on the conclusions of the IPBES report – is likely to cost at least as much, and probably far more.

Rabbits, goats and camels prevent native desert plant community regeneration; rabbits alone impacting over 100 threatened species. Rye grass on its own costs cereal farmers A$93M a year.

Aquaculture diseases have affected oysters and cost the prawn industry $43M.

From island to savannah

Globally, invasive species have a disproportionately higher effect on offshore islands – and in Australia we have more than 8,000 of these. One of the most notable cases is the case of the yellow crazy ants, which killed 15,000,000 red land crabs on Christmas Island.




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Nor are our deserts immune. Most native vertebrate extinctions caused by cats have occurred in our dry inland deserts and savannas, while exotic buffel and gamba grass are creating permanent transformation through changing fire regimes.

Australia’s forests, particularly rainforests, are also under siege on a number of fronts. The battle continues to contain Miconia weed in Australia – the same weed responsible for taking over 70% of Tahiti’s native forests. Chytrid fungus, thought to be present in Australia since 1970, has caused the extinction of at least four frog species and dramatic decline of at least ten others in our sensitive rainforest ecosystems.

Myrtle rust is pushing already threatened native Australian Myrtaceae closer to extinction, notably Gossia gonoclada, and Rhodamnia angustifolia and changing species composition of rainforest understories, and Richmond birdwing butterfly numbers are under threat from an invasive flower known as the Dutchman’s pipe.

Australia’s rivers and lakes are also under increasing domination from invasive species. Some 90% of fish biomass in the Murray Darling Basin are European carp, and tilapia are invading many far north Queensland river systems pushing out native species .

Invasive alien species are not only a serious threat to biodiversity and the economy, but also to human health. The Aedes aegypti mosquito found in parts of Queensland is capable of spreading infectious disease such as dengue, zika, chikungunya and yellow fever.

And it’s not just Queensland that is under threat from diseases spread by invasive mosquitoes, with many researchers and authorities planning for when, not if, the disease carrying Aedes albopictus establishes itself in cooler and southern parts of Australia.




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What solutions do we have?

Despite this grim inventory, it’s not all bad news. Australia actually has a long history of effectively managing invasive species.

Targeting viruses as options for controlling rabbits, carp and tilapia; we have successfully suppressed rabbit populations by 70% in this way for 50 years.

Weeds too are successful targets for weed biological control, with over a 65% success rate controlling more than 25 targets.

The IPBES report calls for “transformative action”. Here too Australia is at the forefront, looking into the potential of gene-technologies to suppress pet hates such as cane toads.




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Past and current invasive species programs have been supported by governments and industry. This has provided the type of investment we need for long-term solutions and effective policies.

Australia is better placed now, with effective biosecurity policies and strong biosecurity investment, than many countries. We will continue the battle against invasive species to stem biodiversity and ecosystem loss.The Conversation

Andy Sheppard, Research Director CSIRO Health & Biosecurity, CSIRO and Linda Broadhurst, Director, Centre for Australian National Biodiversity Research, CSIRO

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Why Australia needs to kill cats


John Read, University of Adelaide and Katherine Moseby, UNSW

Introduced cats are a key threat to 123 of Australia’s threatened species.

The management of cats is challenging and divisive; many options such as rehoming, trap-neuter-release and euthanasia have been used around the world with varying success.

Australia’s recent commitment to killing 2 million feral cats to protect its native wildlife has attracted international attention and some have considered the project harsh.

While the actual target of 2 million has been rightly criticised as arbitrary and more based on public relations than rigorous science, it’s true non-lethal methods are not enough to stem the environmental havoc cats cause. Particularly in light of a UN report highlighting the world’s extinction crisis, Australia urgently needs well-targeted cat culls.




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Non-lethal methods

A range of effective non-lethal methods are already protecting wildlife from cats. Cat-exclusion fences have collectively improved the conservation status of many threatened species. In addition, an increasing number of Australian councils have created progressive cat management bylaws designed to protect pet cats, wildlife and humans from the effects of free-ranging cats.

The centrepiece of many of these bylaws, supported by the vast majority of animal welfare groups, is the containment of pet cats on their owner’s property. Indoor cats live longer, safer lives than cats that are allowed to roam.

Stray cats are harder to manage. These are the cats that do not have a home, but may be directly or indirectly fed by people.




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Because they are unowned, no-one is officially accountable for their health or welfare. Groups of like-minded individuals feed and even provide veterinary assistance to some of these cats, further blurring the distinction between pet and feral cats.

A trend promoted by “no kill” shelters and advocacy groups in some US states and Europe is for clowders (groups) of stray cats to be desexed, vaccinated and released back onto the streets. This process is called trap-neuter-release (TNR).

A recent RSPCA best-practice cat management discussion paper proposed a trial of TNR in Australia too – but there are very good reasons why this would be counterproductive for cat welfare.

The risks of releasing unowned cats

Informed animal welfare advocate groups, including PETA, strongly condemn the release of unowned cats, neutered or otherwise, due to the welfare risks to these cats. Human health professionals and wildlife advocates also oppose maintaining groups of cats.

Dense outdoor cat clowders are hotbeds of toxoplasmosis infections. This cat-borne disease is increasingly being linked to a range of chronic mental health conditions including schizophrenia and Alzheimer’s disease.

“No kill” groups that promote TNR erroneously claim that neutered cats significantly reduce the breeding potential of erroneously named cat “colonies”, in the same way that release of neutered mosquitoes is a proven technique for controlling disease-bearing mosquitoes.

One of us (John) has recently written a book on protecting wildlife and cats that suggests five fatal biological flaws in this logic:

  1. Neutering mosquitoes works because impotent individuals “swamp” short-lived wild insect populations that mate only once. By contrast, female cats typically mate repeatedly when on heat, so an encounter with a neutered tom is of little consequence.

  2. Unlike lions, domestic cats evolved as solitary hunters. While domestic cats can tolerate living in high-density clowders, they do not form hierarchical colonies, packs or prides where alpha individuals restrict the feeding, breeding or survival of subordinate animals.

  3. Although loud cat fights might make you assume males fight over the right to exclusively mate with a female, most litters of outdoor cats are sired by multiple males. Even supposedly “dominant” males seldom intervene when another male courts a female. Neutered male cats will not protect females in their clowder from non-desexed interlopers. This means that more than 90% of cats need to be neutered to restrict population increases, an incredibly challenging proposition.

  4. Despite the misleading label “colony”, cat clowders are not closed populations. Rather, cats typically move around to take advantage of abundant food resources. And unwanted pets are often dumped at clowder sites. The failures of several well-studied TNR programs are attributed to cats migrating or being dumped at these sites.

  5. Despite needing repeated vaccinations to protect them from debilitating diseases, few stray cats can be captured a second time. And many can never be captured at all. This leaves them and their clowder effectively unmanageable.

TNR is biologically flawed, cruel to cats – because it returns them to a hazardous environment – and ineffective when not accompanied by high levels of adoption.

Harming marine ecosystems

Not only do predatory cats harm native wildlife, but stray or feral clowders can also directly influence marine ecosystems and fisheries.

Many commercial cat foods contain increasingly threatened predatory fish that are high in the food chain and hence use more nutrients and biological energy than plants or herbivores. US dogs and cats consume one-third of the animal-derived protein eaten by humans, with accompanying greenhouse gas emissions.

The cat food provided to stray clowders adds to this biological expense. In 2009 alone, the US-based Best Friends Animal Society, one of the major promoters of TNR, distributed over 80,000 tonnes of cat food to unowned cats. There are no similar studies in Australia, and we appear to have far lower rates of stray-cat-feeding, but it is still part of the ecological impact of stray cats.

Even more insidiously, seals, otters and dolphins in oceans around the world die from cat-borne diseases spread mainly from clowders.




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Humane euthanasia

Fortunately, both science and animal welfare standards are consistent about management of cats. All healthy domestic cats for which safe homes can be found should be adopted or rehomed, then kept indoors following neutering and vaccination. All other cats, including ferals and strays that cannot be rehomed quickly, should be humanely euthanased.

Feeding or releasing cats (neutered or otherwise) threatens our wildlife and perpetuates the cycle of suffering, disease, predation and social annoyance. Non-lethal options such as feral cat-proof fencing can still be part of the solution, but euthanasia remains an important part of controlling feral and stray cats to protect our native wildlife.


Among the Pigeons: Why our cats belong indoors (2019) by John Read is published by Wakefield Press.The Conversation

John Read, Associate Lecturer, Ecology and Environmental Sciences, University of Adelaide and Katherine Moseby, Research fellow, UNSW

This article is republished from The Conversation under a Creative Commons license. Read the original article.