Archive January 2013

SPCA’s cruelty to cats and other animals – Are they mad? - Wayne Linklater Jan 30


Trapped, neutered and released stray and feral cats continue to inflict pain and suffering on native wildlife and people. Hunting cats, not part of the  native ecosystem, torture and kill other animals unnecessarily. Diseased stray and feral cats, when threatened or cornered inadvertently, will bite and scratch to injure, and transmit diseases to people. Why does the Society for the Prevention of Cruelty to Animals not care about preventing cruelty in other animals, only cats?

The SPCA’s support for trap-neuter-release (TNR) programs becomes even more bizarre when we consider that TNR also inflicts pain and suffering on cats… yes cats! There is a strange belief that animals alive have better welfare than dead animals, even though they are subject to lives that are cruel. TNR programs inflict suffering on cats.

Stray cats are diseased, full of parasites, and often malnourished towards suffering, pain and death. The life span of feral cats is estimated to be 5 times shorter than owned cats and death rates as high as 80% [1]. Stray and feral cats live cruel, short lives. Moreover, de-sexed cats are less aggressive and less likely to defend themselves. Migrating entire cats, especially males, attack, injure, and displace de-sexed cats.

When de-sexing stray and feral cats, surgeons will inevitably sometimes be de-sexing felines that are late-pregnant. That means killing near birth foetuses of whole litters in a process that is a much slower death than the mother’s euthanasia.

TNR programs are crueller to stray and feral cats than the going to sleep and never waking up again of euthanasia. TNR programs satisfy the animal welfare credentials of only a few self-interested groups. A broader more robust assessment of animal welfare would not support TNR programs for cats in New Zealand.

Yes – they are mad

The claims that advocates of TNR make have been scientifically evaluated and shown to be false several times [2].

A recent socio-psychological survey of people involved in the care of feral cat colonies and TNR programs found their attitudes and motivations to be “rooted in lack of knowledge and mistrust” [3]. I doubt the ‘sanity’ of TNR programs and it seems we should also question whether those that conduct them are rational and reasonable people.

The evidence is in. Dr. Gareth Morgan is right to point the finger at the SPCA for supporting TNR of cats – it is mad. They are mad, quite mad.

Until such time as the SPCA stops TNR they have lost my support. In previous posts I have advocated conservationists engage with animal welfare agencies to help achieve solutions. I do not think the SPCA should be considered amongst those groups for the moment.

Fortunately, not all SPCA centres support TNR – some know it is flawed. Give support to SPCA-Waikato for working with groups to address the cat problem humanely and rationally.

Bob! – take Morgan’s $5 – you will be doing cats and our other animals everywhere a favour.



1 Jessup, D.A. (2004) The welfare of feral cats and wildlife. Javma-Journal of the American Veterinary Medical Association 225, 1377-1383

2 Longcore, T., et al. (2009) Critical Assessment of Claims Regarding Management of Feral Cats by Trap-Neuter-Return. Conservation Biology 23, 887-894

3 Peterson, M.N., et al. (2012) Opinions from the front lines of cat colony management conflict. PLoS One 7


Trap-neuter-release or Trap-kill-$5? - Wayne Linklater Jan 30


To my horror, but thanks to Dr. Gareth Morgan’s recent announcement that he will donate $5 to Bob Kerridge’s SPCA for every cat they euthanize rather than release, I discovered that some factions of the SPCA are releasing cats into our cities, towns and countryside – lots of cats. Bob Kerridge – CEO SPCA – is considered a hero by a few for it. They call it trap-neuter-release – TNR

But TNR is not a solution

TNR programs do not stop the cat problem because cat numbers can only decline when a cat dies. But more cats are abandoned and migrate into the colony from other places to replace those that die [1]. Indeed, the presence of TNR in a neighbourhood is likely to encourage some domestic cat owners to release and abandon their cats – knowing that they will be cared for. The problem, therefore, is not solved.

TNR is not a viable solution when stray and feral populations are large [2] like in our major cities and wilderness. Success depends on de-sexing the majority of the population and getting them before they breed. Achieving those capture rates is extraordinarily difficult. Cats try not to be caught. A proportion of cats will not be caught and continue to breed.

TNR of so many colonies and so many cats takes constant monitoring, coordination and extraordinary resources. When that investment is not achieved or periodically fails to be maintained, which is inevitable for most colonies some of the time, cat colonies recover and grow again.

The ‘cat lovers’ who care for stray and feral cat colonies are also unlikely to be motivated to push TNR colonies into decline and eventual disappearance, even if it were possible, because they would be out of a cause or out of a job. It is more likely that they will just manage colonies of stray and feral cats in perpetuity. Indeed, in programs around the world those TNR programs that do reduce colonies end up with many small managed colonies requiring on-going investment, not the removal of the stray and feral cat problem [3].

The few TNR programs that were reportedly successful were only small populations where adoption campaigns could also remove a large number. The capacity of the human population to absorb cats is limited. We already have one of the highest cat ownership rates in the world.

TNR protects disease and predators of our native wildlife

Disease and parasites are a major problem of stray cat colonies in cities. They vector diseases to other domestic pets and people, including toxoplasmosis – a disease carried by cats which infects 40% of New Zealanders at some time in their lives and cannot be cured.

De-sexed stray and feral cats continue to impact native wildlife and on a much greater scale than anyone imagined. Stray and feral cats cause the greatest harm because they hunt to survive.

TNR does not address the human health and native wildlife problems – stray and feral cats even de-sexed continue to carry and transmit disease and kill native wildlife. By managing colonies of stray and feral cats we are effectively maintaining a reservoir of infection, disease and native animal predators for the future – madness.

Bob! – take Morgan’s $5 – you will be doing New Zealand and New Zealanders a favour. If the SPCA doesn’t accept the offer they’re mad.

How mad? – see my next post.



1 Castillo, D. and Clarke, A.L. (2003) Trap/neuter/release methods ineffective in controlling domestic cat “colonies” on public lands. Natural Areas Journal 23, 247-253

2 Guttilla, D.A. and Stapp, P. (2010) Effects of sterilization on movements of feral cats at a wildland urban interface. Journal of Mammalogy 91, 482-489

3 Jongman, E. and Karlen, G. (1996) Trap, neuter and release programs for cats: A literature review on an alternative control method of feral cats in defined urban areas. In Urban Animal Management Conference Proceedings, pp. 81-84, Australian Institute of Animal Management Inc.




Cat-harsis – solutions aplenty and possible - Wayne Linklater Jan 29

No Comments


Indoor cats and cat runs, like the one illustrated, are more common in other countries but also possible in New Zealand. Indoor cats live longer healthier lives and cannot kill native wildlfe.

I began writing about solutions to the cat problem by suggesting conservationists appeal to cat owners’ self-interest and the health and well-being of cats so that increasingly cats are de-sexed and indoors, especially from before dusk to after dawn.

Collars with owner contact tags not only help ensure the safety and well-being of your cat but if you add a bell or bib they substantially reduce the number of native animals your cat kills. Studies in New Zealand and around the world have found cat kill-rates are reduced by up to 51% if they wear bells or bibs.

Solutions will be more widely adopted and permanent if they make sense to cat owners for reasons other than just the protection of native wildlife. De-sexed domestic cats free-roaming less often and wearing collars with bells or bibs when they are, however, is unlikely to entirely solve the problem. Some owners will be intransigent and some negligent. Not all owners care all that much, even about their cat – hence the need for organisations like the SPCA.

Nevertheless, this initial approach by conservationists will open a positive dialogue with cat owners towards other solutions that will require that cat lovers also look beyond their own interests. The dialogue will allow us to solve the more intractable problem that unwanted kittens will still be born, and cats will still be lost or abandoned to become strays in our neighbourhoods and feral in wilderness.

Unfortunately, the problem is not helped by the legal definitions of domestic, stray and feral cats in New Zealand. The definitions are blurred in ways that prevent a reduction in stray and feral cats in places where people live [1]. The problem arises because stray cats in human-dominated environments are not legally defined as feral, although they have the same effect on native wildlife in city reserves, parks and gardens as a feral cat in wilderness.

And unfortunately, stray cats are common. Large populations form in our cities – sometimes near biodiversity sanctuaries [2]. I believe, therefore, that economically, socially and ecologically effective management of the cat problem requires improved policy and regulation of the domestic cat in New Zealand. Owner or cat registration and identification (like mandatory microchip implants) would assist in demarcating domestic from stray cats and, therefore, stray cat management. Legislation to more clearly distinguish the domestic from stray cat and to empower local authorities to control stray cats is necessary.

A cat caught by the Department of Conservation after it killed at least 102 bats from the same colony near Okakune.

Some places where we live are more valuable to native wildlife than others and biodiversity sanctuaries and their wildlife require greater protection from cats. The expectation that if you allow your cat to stray into such special places it can be caught and euthanized is reasonable encouragement for cat owners to manage their cats’ behaviour – in the same way that domestic dogs killing kiwi in National Parks are reasonably euthanized. ‘No Cat Zones’, or at least no out-of-door cats, may also be reasonably expected around such special places. No cat neighbourhoods which provide a 1.2 km buffer to our cities’ wild places are likely to develop in the near future – 2.4 km buffer zones in rural areas [3].

I reserve the last word to speak on behalf of cat owners who, in a recent survey, demonstrated that they largely de-sex their cats already (92% in Auckland) and are not just cat lovers but lovers of all wildlife. Cat owners expressed stronger conservation values than non-cat owners [4]. As conservationists we need to harness the conservation ethic of cat owners and appeal to their values. Many cat owners will support better legal and regulatory management of cats, even if the few noisy ones do not. Conservationists should appeal to the majority of responsible cat owners with conservation values to, necessarily, divide-and-rule.



1 Farnworth, M.J., et al. (2010) The Legal Status of Cats in New Zealand: A Perspective on the Welfare of Companion, Stray, and Feral Domestic Cats (Felis catus). Journal of Applied Animal Welfare Science 13, 180-188

2 Aguilar, G.D. and Farnworth, M.J. (2012) Stray cats in Auckland, New Zealand: Discovering geographic information for exploratory spatial analysis. Applied Geography 34, 230-238

3 Metsers, E.M., et al. (2010) Cat-exclusion zones in rural and urban-fringe landscapes: how large would they have to be? Wildl. Res. 37, 47-56

4 Farnworth, M.J., et al. (2011) What’s in a Name? Perceptions of Stray and Feral Cat Welfare and Control in Aotearoa, New Zealand. Journal of Applied Animal Welfare Science 14, 59-74




Conservationists should care about cats - Wayne Linklater Jan 28

1 Comment

– the least cost, least resistance, and most sustainable solution to the domestic cat problem.

Debates that divide communities are especially emotional and irrational when one side attempts to impose a solution. Inevitably the imposition will result in an equal (or stronger) and opposite resistance from the other side. Positions become entrenched and solutions are not achieved – even when they are advantageous.

The recent controversy about domestic cats and cat ownership is a debate like this. Reactions to solutions like cat registration and ownership controls lead to speculations about regulated euthanasia, and unhelpful headlines and quotes like “take people’s kittens away” and “Morgan calls for cats to be wiped out” - just silliness.

Real and sustainable solutions to the domestic cat problem will only be found if conservationists transcend this debate and engage positively with cat owners.

Fundamentally the conservation lobby needs to acknowledge and accept that most people, including cat owners, do not care enough about native wildlife to change their behaviour – prevent their cats killing native animals or choose not to own a cat. This is not going to change in the foreseeable future. Suck it up greenies. Wake up and smell the coffee.

So ask yourself…

What do cat owners care about?

They care very much about the health and well-being of their cats.

What measures would improve cat health and well-being but, secondarily, also reduce how frequently cats kill wildlife?

Cat hit by car but still alive. It is cruel not to keep your cat indoors. Source: The PETA files (

Cat deaths and injuries requiring veterinary intervention are common. They cost owners emotionally and financially. A leading cause of admissions of cats to veterinary clinics is cats fighting and motor vehicles. Some vets report “over 90% of septic wounds in cats result from cat bites sustained during a cat fight”. One vet recounts “At least 4 cats owned by either me, or my family while I was growing up, were killed by cars and another three were badly injured but survived”. This experience is common. So common, crippling and costly are injuries to cats from fighting and traffic that many veterinarians recommend that cats have indoor lives.

Cat owners who de-sex their cat are less likely to pay expensive veterinary bills. De-sexed cats fight less. Cats who are kept indoors, but especially at night, are less likely to fight or be hit by vehicles. And owners that do not leave food outside for their cats are less likely to attract other cats to their properties that fight.

Fortuitously, these are also measures which are likely to reduce the chances of your cat killing wildlife. Cats kill most native animals at dusk, during the night, or at dawn. A cat cannot kill native wildlife in the garden if it is not in the garden. When food is not left outdoors we do not support stray and feral cat populations. De-sexed cats range less and do not contribute unwanted kittens to abandoned, stray and eventually feral cat populations.

By appealing to cat owners to do the right thing for their cats we are more likely to reduce predation on native wildlife. We are appealing to the cat owner’s self-interest. Goodness… the mutual respect that such an approach might generate between conservationists and cat owners might make the co-existence of domestic cats and native wildlife possible, especially because the engagement makes other less tractable solutions possible (but more on those in the next post).

Cat owners are more likely to support regulation and controls on cat ownership if they are explicitly targeted at improving cat welfare. Cats killing wildlife might be reduced just enough to allow vulnerable native species to live where we do.

I advocate a redirected and renewed campaign by conservation agencies (engaging with the SPCA and veterinary associations) which highlights for people the cat health and financial advantages of cats indoors. Bugger the biodiversity – it is irrelevant.

More solutions in my next post, especially for those cat owners that do also care about native wildlife.



When the cats away… … people do the killing - Wayne Linklater Jan 27


- why getting rid of domestic cats will not result in more rats killing more wildlife.

One of the leading cautions after Dr. Gareth Morgan’s call for controls on cat numbers and ownership was the concern that if cat numbers were reduced other predators of native wildlife, especially rats, would increase in number because cats also eat rats.

Ecological science calls this phenomenon meso-predator release – ‘meso’ as in middle or intermediate predator. In the debate about domestic cat control the mesopredator is the rat and the top predator is the cat. Mesopredator release has been described in lots of wilderness ecosystems where removing the top predator resulted in an out-break of the mesopredator and an increase in predation of the prey [1].

The Mob?

Cats might control rats not just by killing them but also because rats fear cats and avoid areas where cats are. Indirectly as well as directly, therefore, the cat might protect native wildlife.

Cats might be like ‘the mob’. They protect native wildlife but extract a high price for doing so. The price cats’ demand just isn’t as high as the price that more rats would extract. Indeed, in New Zealand wilderness, rats are feral cats’ preferred prey. Cats will hunt rats even when the rats are uncommon and hunt birds only secondarily. Birds are a less attractive meal than rats. They have less meat and fat on their bones and are harder to catch because they fly [2].

Nevertheless, we need to be cautious about claims of mesopredator release in New Zealand ecosystems. Although there is a lot of speculation that mesopredator release might occur there is little evidence for it. Currently, some of the most cited studies in support of the idea in New Zealand are just mathematical models [3, 4].

Nevertheless, I think the evidence from other countries indicates that mesopredator release is likely – at least under some circumstances. So let us assume, for the moment, that mesopredator release – rat outbreaks – occur in New Zealand’s native forest and grassland ecosystems when feral cats are controlled. But we shouldn’t assume that mesopredator release will also occur in the ecosystems we live in – urban and agricultural landscapes – when our companion cats are reduced in number.

Why wouldn’t rat out-breaks also occur in urban and agricultural ecosystems if free-roaming domestic cats were controlled?

One very important and blindly obvious reason… US! – you and me.

The ecosystem that domestic cats live in is very different from wild ecosystems because people live there. In the ecosystem where we live, work and play we already control rats for lots of reasons and the protection of native wildlife does not rank highly among them.

We kill rats to protect our food. We kill rats to protect our homes from damage. We kill rats to prevent the spread of disease. We kill rats to protect our businesses and infrastructure. All of these are compelling reasons for killing rats to almost all of our community. WE ARE NOT GOING TO STOP KILLING RATS!

Unlike the debate about domestic cats predation on wildlife which appears to divide New Zealand, we are united in our disgust of rats. People have killed and controlled rats for as long as we have been people. Cat owners and conservationists are united in their loathing of feral rats.

A reduction in cat numbers is unlikely to result in a widespread increase in rats to levels that would impact native wildlife in urban and agricultural landscapes because people are highly motivated to kill rats. A rise in the rat population would not go unnoticed by the rat-hating human population. Any increase in rats would be met by an increase in trapping and poisoning by people in all the ways we already do and including the new hi-tech traps now available.

Urban ecosystems are different from wild ones – mainly because people are a major predator of all things great and small – but especially rats.

Next post: ways of reducing domestic cat predation of wildlife. Some ways are more acceptable, feasible and effective than others. Success will require multiple approaches and tools.



1 Ritchie, E.G. and Johnson, C.N. (2009) Predator interactions, mesopredator release and biodiversity conservation. Ecology Letters 12, 982-998

2 Harper, G.A. (2005) Numerical and functional response of feral cats (Felis catus) to variations in abundance of primary prey on Stewart Island (Rakiura), New Zealand. Wildlife Research. 32, 597-604

3 Courchamp, F., et al. (1999) Cats protecting birds: modelling the mesopredator release effect. Journal of Animal Ecology 68, 282-292

4 Fan, M., et al. (2005) Cats protecting birds revisited. Bulletin of Mathematical Biology 67, 1081-1106




Do domestic cats exterminate native animal populations? - Wayne Linklater Jan 24


Domestic cats kill native animals – fact.


… just because our cats kill it does not necessarily mean that native animal populations cannot co-exist, or even thrive, where our feline companions live.

Two considerations determine whether cat-kill exterminates native prey populations:

1. how many cats there are, and

2. how fast native animal populations in our backyards reproduce themselves or recolonize our backyard (immigration) when the previous native animal is killed.

The more cats there are, the more native animals can be killed, and the more likely that cat-kill will exceed the capacity of native animal populations to replace themselves. But some native animals are faster reproducers than others – they raise larger numbers of offspring. Fantail may raise up to 5 clutches of 2 to 5 eggs each year but Kereru (NZ pigeon) is more likely to have just one clutch and egg each year. Habitat will also influence how fast native animals can replace themselves. The native animals in neighbourhoods with better habitat, because they are treed or near regenerating bush, may reproduce more.

Thus, the resilience of native animal populations to cat predation or, to put it from the cat’s perspective, achieving a sustainable hunt (harvest) of native prey, depends on the balance we strike in our neighbourhoods between having cats and habitat for native animals.

If we measure how fast native animals replace themselves, and combine the estimate with known cat-kill rates, we can know if native animal populations will co-exist with our cats. Fortunately, these measures and comparisons have been made.

Cat-aclysm measured

In Reading, United Kingdom, 6 common bird species were sometimes brought home dead by domestic cats in greater numbers than were alive in the adult and breeding population [1]. Cats, therefore, had the capacity to significantly reduce the size of local populations for common urban birds. Not all studies suggest that the amount of killing by cats is enough to exterminate native animal populations. Enough do, however, for us to want to conduct similar studies in New Zealand.

Fortunately, this has already been done in Dunedin by Dr. Yolanda van Heezik and her research group at the University of Otago. Domestic cats in Dunedin City killed silvereyes, bellbirds and fantails – 3 native bird species - at a rate faster than those birds could establish and reproduce [2]. This was also true for exotic birds like house sparrow, blackbird and song thrush. So severe was the kill rate for fantail that cats were catching more than were bred.

Thus, the persistence of these native and exotic birds in Dunedin, and perhaps other New Zealand cites, may depend on them colonising from somewhere else. The cat densities in Dunedin responsible for such kill rates are typical of other New Zealand cities. About 35% of Dunedin households had at least one cat resulting in about 223 cats per urban square kilometre. At these cat densities Dunedin’s native birds were not resilient to predation and the cat harvest was not locally sustainable.

Mr Robert Kerridge, CEO SPCA, is reported to have said that “fewer than half of New Zealand’s domestic cats killed other animals. The ones that did caught far more rodents than birds”. What he says is only sometimes true. And even when it is true the kill-rate of native animals may still be large enough to cause native animal populations to decline. The density of cats in our cities generates a kill rate sufficient to exterminate native animals from our backyards and neighbourhoods.

The solution to cat-kill will most likely come from reducing the ability of cats to kill or the number of cats, and improving our neighbourhoods as habitat for native wildlife. How we achieve these in ways that are acceptable to our diverse community, including many cat owners, will be the subject of a future post.

For the next post, however, I will treat the problem of unintended consequences. Even if we accept that cat-kill needs to be reduced, might the environmental costs out-weigh the benefits for native wildlife? Some, for example, have cautioned that a reduction in cat-kill will just mean rats become a more serious problem because cats also hunt rats. Could cats be good because they are the lesser of two evils?

I will meet this problem head on next.



1 Thomas, R.L., et al. (2012) Spatio-Temporal Variation in Predation by Urban Domestic Cats (Felis catus) and the Acceptability of Possible Management Actions in the UK. PLoS One 7

2 van Heezik, Y., et al. (2010) Do domestic cats impose an unsustainable harvest on urban bird populations? Biol. Conserv. 143, 121-130




Do domestic cats really kill native wildlife? - Wayne Linklater Jan 23


The commentary of the last few days following Dr. Gareth Morgan’s media release has focussed too much on the messenger and how the message was delivered rather than understanding the problem and potential solutions. Some have described his views as extreme but whether or not they are extreme is less important than whether or not they are supported by evidence. Desicion-making in environmental policy should follow the evidence like it does in medicine, law and engineering. Let us move beyond the messenger and message and discuss evidence for a cat problem – is there a problem? – and the potential solutions that evidence informs – what solutions are best?

Cat-astrophy measured

Studies show that there is enormous variation between our domestic cats in their propensity to kill native wildlife. Some cats rarely kill while others kill frequently. If your cat is killing it will sometimes return home with its kill, although some cats do this more than others and some not at all. In Dunedin, only about 1 in 4 domestic cats bring prey home [1]. In a UK study about 40% of cats came home with their prey [2].

The interesting use of micro-cameras on domestic cats in the US – KittyCams – showed that only a quarter of cats’ prey was brought home. About 30% of prey was eaten and 50% left uneaten at the kill-site. Thus, even if you never see you cat with prey, it may still be killing.

New Zealand studies of domestic cat killing have relied on estimates from documenting the prey a cat brings home and so certainly under-estimate how much killing domestic cats do. Nevertheless, these studies are instructive for their local relevance.

NZ studies show that 13 animals are brought home per year by cats. If that is a quarter of total kill then the figure inflates to around 50 animals a year – one per week per cat. But about a third of NZ domestic cats do not hunt [1]. The reason why so many animals can be killed but a large number of domestic cats not hunt is that some cats kill an awful lot.

In the US study with KittyCams on 55 cats, 16 cats (29%) killed animals at an average rate of 2 animals per week. Most killed just one or two animals a week but some killed as many as 5 a week. Goodness – that would approximate 250 wildlife killed a year by one cat! Most domestic cats are not killing or killing only a little, but a few kill a tremendous amount.

We do not know at this time for New Zealand what most influences some domestic cats to hunt more than others. Characters of the cat like age and breed, or the owner’s behaviour like how much time they spend home might be important. More research is required on this question because it may be that there are small measures an owner can take to substantially reduce a cat’s killing. Nevertheless, we do know that you can reduce your cats kill rate of birds by as much as 50% by making it wear a bell [3] – please do. Cat collars with bells are a pre-cautionary, albeit imperfect, solution until we can contribute other solutions.

Fantail – highly vulnerable to predatory cats. Source:

We also know that if native wildlife is more common where your cat lives, and the cat hunts, then they will kill more native wildlife [1]. If you live near a park or reserve, or well treed neighbourhood, your cat is likely to be killing more native animals. If you live in an area without native wildlife – perhaps because introduced predators like cats prevent them from living there – then your cat will be killing native wildlife less often. The success of your local biodiversity santuary or your the neighbour’s attempts to restore native wildlife to the area is likely to depend on reducing the number of rats, stoats, ferrets and cats where you live.

The Common Skink is a very widespread lizard species in New Zealand. Source: Trent Bell,

You might also be surprised how much native wildlife is in yours and your neighbours’ gardens. In surveys of Wellington and Dunedin suburbs native birds and reptiles are surprisingly common, although most residents are unaware of the reptiles. The US KittyCam study found that the prey brought to the residence underestimated the number of reptiles killed – they are more likely than birds to be left where they are killed.

Some, like the SPCA’s Robert Kerridge, claim that well-fed domestic cats do not kill wildlife or the kill is trivial. The evidence shows that this is not true. In our neighbourhoods enough domestic cats are owned such that there will inevitably be some who kill a lot. Some of those killed will be native animals, especially where wildlife is common around local parks and reserves.

Nevertheless, even if domestic cats kill, it is still possible that the number they kill is not substantial enough to prevent native populations from thriving. Fortunately, there is evidence from New Zealand and internationally that also addresses this question. In a follow-up post I answer the question ‘do domestic cat populations exterminate native animal populations?’



1 van Heezik, Y., et al. (2010) Do domestic cats impose an unsustainable harvest on urban bird populations? Biol. Conserv. 143, 121-130

2 Baker, P.J., et al. (2008) Cats about town: is predation by free-ranging pet cats Felis catus likely to affect urban bird populations? Ibis 150, 86-99

3 Gordon, J.K., et al. (2010) Belled collars reduce catch of domestic cats in New Zealand by half. Wildl. Res. 37, 372-378



Cat-astrophy in search of solutions - Wayne Linklater Jan 22


Gareth Morgan’s call for the gradual reduction in cat numbers and ownership, especially from parts of New Zealand near places where our nation’s biodiversity live is a welcome ‘public face’ to a long-running discussion amongst ecological scientists and conservationists.

Commentators and media, unfortunately, have made a hash of Dr. Morgan’s suggestion – reinterpretation towards misrepresentation. It is too easy to grab attention and sell advertising by claiming that Dr. Morgan is pitting conservationists against cat-lovers in ways that are unnecessary and inflammatory. Such mis-representation of his approach and argument is not the way forward on this issue. Dr. Morgan, however, can see the way.

Dr. Morgan has not advocated “taking peoples kittens away”, euthanasia, or wholesale removal of all domestic cats in the short-term – even if that might be laudable long-term (think 100 years). Instead he has suggested policy on cat ownership, regulation, and voluntary non-replacement, especially targeted at areas where our native biodiversity is most valuable and vulnerable, like around biodiversity sanctuaries.

Importantly, Dr. Mogan has understood the complexity of the human-cat relationship at community scales and has engaged with the public to encourage non-replacement. This is social communication and marketing meets ecological science at its best. Good on him for engaging in this way with aspirational goals but also reasonable mechanisms to achieve them. A ‘conversation’ that engages with the wider and diverse public constructively in debate and action.

Unfortunately, other agencies did not engage constructively with the topic or Dr. Morgan. In particular, the response of SPCA representatives was not nearly as considered. I wonder whether SPCA CEO, Robert Kerridge, regards the SPCA as the Society for the Protection of Cats Ad nauseum, rather than the Society for the Prevention of Cruelty to Animals that it is. It is certain that cats can be reduced in number in New Zealand in ways that assist conserving biodiversity and protect the environment without cruelty. SPCA’s mandate is to prevent cruelty, not protect cats. I think they have over-stepped.

An argument can also be launched that cats are a cause of significant cruelty to native animals. By not protecting the rights and welfare of native animals we could be regarded as flagrantly unethical. The rights and welfare of native animals and the rights of New Zealanders to access, enjoy and benefit from our nations native biodiversity are diminished by the super-abundance of cats in our landscapes. A cat owner pursuing the right to have a cat without regulation, impinges on the rights and welfare of other native animals and people. New Zealand is for all New Zealanders. Not just cats and cat owners. Can they learn to share?

In a follow-up post I will debate the evidence for cats killing New Zealand’s native wildlife. It is critical that our decisions, actions and policies be evidence based. Fortunately, science is available to inform these things and we can do a good job of ensuring that a solution is found in ways that are largely supported by our communities.

A new 3 R’s for the environment - Wayne Linklater Jan 15

1 Comment

The 3 Rs, Reduce, Reuse, Recycle, have become a mantra – an axiom with extraordinary reach across communities, cultures and nations for the more efficient use of natural resources, primarily by reducing waste. It is a leading example of the power of slogan and motif – communications and marketing – to change environmental behaviour.

Reduce, Reuse, Recycle, also called the waste hierarchy, originated during World War II when shortages of raw materials motivated more conservative resource use, especially of metals, rubber, and wood as timber and paper.

The concept developed after the war to sustain economies with on-going shortages. A failure in the supply of raw materials to any part of the manufacture chain, even temporarily, spelt doom for companies and the shocks would be felt through the economy. Thus, Reduce, Reuse, Recycle was a tool for economic stabilisation.

It should not surprise us, therefore, that there is a growing consensus between environmental and economic (business) interests – deterioration in the quality and quantity of resources affects us all. Conflicts between environmental and economic interests are a luxury of communities with plenty, or the folly of communities with delusions of plenty.

Reduce, Reuse, Recycle was adopted by the environmental movement during the 1970s as a way to reduce waste that would otherwise pollute. In recent years the concept has also been applied by businesses to improve profitability. Waste is costly to dispose or recover. There is also market risk and opportunity to businesses whose brands’ value may be tarnished by environmental impact or enhanced by environmental stewardship.

Gary Anderson (right) and his mobius loop desgn for Reduce, Reuse, Recycle. Source:

The axiom came to be symbolised and globally recognised by the Mobius loop – a motif designed by Gary Anderson, a 23-year-old-college student. Gary’s account of his experience is available from The Financial Times. His was the winning entry for an art contest sponsored by a Chicago-based recycled paperboard company to raise environmental awareness amongst high schools and colleges across the USA. The motif ranks today with other international commercial brands for ubiquity and recognition but Gary earned just a couple of thousand dollars for his design.

In applied ecological science there are another three Rs with much greater environmental value: reservation, restoration, and reconciliation ecology. These are not yet united by a slogan and they do not yet have their own motif. Nevertheless, their recognition as complementary applications of ecological science to environmental stewardship needs development and wider recognition. Unfortunately, reserved, restored and reconciled habitats, and their advocates, are too often regarded in opposition.

In a future post I will introduce the concepts of reservation, restoration and reconciliation ecology and argue that we need to integrate them better towards resilient landscapes that sustain biodiversity and natural resources.

Whipping the poor to garden – an ecological injustice - Wayne Linklater Jan 06

1 Comment

Weekly newspaper columnists most often opine on people and society. Michael Laws, in his weekly Sunday Star Times column, has a particular trenchant for admonishing people with fewer resources than himself.

This Sunday, Laws advocated gardening to the poor in “Want to eat well? Simply grow your own food” (Sunday Star Times January 6th). Seldom do weekly columnists tread into ecological territory and, being an amateur but enthusiastic gardener myself, I read with interest.

It is not the first time the poor have been chastised for not gardening. Every so often a politician or self-righteous ‘green-thumb’ will also imbibe in this ecological solution to being impoverished. But is the criticism for not gardening fair, and is gardening a viable solution to being poor?

Gardening is an ecological problem made more challenging by its interaction with human behaviour and economics. Mr Law’s central tenants are that gardening is easy and that it results in a net economic gain to the household. He is dreaming.

The Fertile Cresent – the largest area on the planet with both rich alluvial soils and a Mediterreanean climate – ideal conditions for gardening.

Gardening was a late advance in human societies because it is difficult and constrained by opportunity – the fortuitous coincidence of multiple favourable circumstances at once. Growing plants for food occurred first along the Euphrates and Tigris Rivers and eastern coast of the Mediterranean Sea called, appropriately, the Fertile Crescent. The Fertile Cresent was the largest area on the planet with the coincidence of rich alluvial soils and a climate of mild, wet winters and long summers [1]. It is much harder and more costly to garden in most other places on the planet.

The first plants domesticated – wheat, barley and peas – weren’t cropped until just over 10,000 years ago, although our species has been smart enough for gardening for a lot longer than that. We domesticated animals earlier – training wolves to dogs over 13,000 years ago in western Russia and central Europe – and have harnessed fire, made tools, and communicated with language for much, much longer still [2].

Gardening also developed very slowly. Hunter-gatherer societies did not become agriculturalists overnight. They made a gradual transformation to sedentary communities that grew their food because attaining the experience and knowledge to garden well took several millennia. Gardening is not an easy thing to do – even for brainiacs.

My daughter picking raspberries under the cabbage tree – nothing else would grow there.

Although our society has solved many of the problems which faced the first gardeners, several of the original challenges remain. A coincidence of five conditions of our ecology must still occur for gardening to be easy and economically viable in the modern world (and while I list these challenges let me boast pictorially about my ‘world famous to my daughter’ zucchinis, raspberries and beans – illustrated – many more failures not illustrated). You must:

1. have a site to garden and certain tenure and security of your site,

I had wonderful zucchinis last year. Looks like a good crop this year too. My first year’s crop failed – seeds rotted in the ground.

2. start-up resources (funds, equipment, materials, time) available to invest and sufficient to succeed,

3. have soil and micro-climate at the site suitable for growth,

4. be in a place that is unlikely to suffer extreme ecological events (weather or pests) capable of destroying your crop, and

Beans, glorious beans. Broad ones finishing, and Scarlet Runners just beginning. Broad beans were my first success – robust to clay soils. Scarlet runners are perrenial lovelys, but my first season of these failed.

5. already be garden-wise.

If you invest in a garden but any of these conditions is not met, and a net economic return is your measure of success because you are poor, then you will fail and become poorer still. This is why those that garden well are garden proud. Gardening well is a magnificent achievement of socio-ecological intuition and science.

Is Michael Laws naïve? To some extent. But I also suspect him of giving the poor another hiding – he is a feral columnist. This time he has chosen to thrash them with an ecological stick – a false solution and he is wrong to do so. In future posts I will embellish on these five conditions to explain why our ecology makes gardening for food largely a luxury of the middle classes.



1 Diamond, J. (1999) Guns, Germs, and Steel. W. W. Norton & Company, Inc.

2 Clutton-Brock, J. (2012) Animals as Domesticates. Michigan State University Press.

Network-wide options by YD - Freelance Wordpress Developer