Essay 4. From Pet to Pest: Snakes, Wildlife, and Australia’s Feral Cat Crisis

“Oh, you can’t help that,” said the cat. “We’re all mad here. I’m mad. You’re mad.”

― Lewis Carroll, Alice in Wonderland

 

Until very recently, I’d never received hate mail. While certainly a more benign and harmless variety than that which might be faced by public figures, it did catch me by surprise. In early 2016, during a rather eventful morning of snake removal, I filmed a wild carpet python (Morelia spilota) consuming a cat which it had caught and killed perhaps an hour earlier in suburban Brisbane. Belonging to the client’s neighbor, the cat had evidently been out roaming the night/early morning in our client’s back yard when a rather hungry 2 meter long python struck. Constriction and expiration would have been quick. The client’s called us around 6am after finding the python constricted around the lifeless cat, and by the time we arrived the snake’s jaws were unhinged and beginning to consume its prey in typical head-first fashion. With no hope for kitty, the pet’s owners informed, and breakfast commencing right in front of us, what choice was there but to film this incredible feeding event? Later that afternoon, I posted online an edited, close-up, time lapse video of the cat being eaten, naively forgetting that the internet is, in large part, a hate-machine powered by cat videos.

I had hoped to perhaps inspire some discussion on cats, conservation, and pet ownership in Australia. Such hopes were largely dashed as the video went viral and torrents of emotion flooded the comment sections. While I had the genuine pleasure of many interesting and generally productive correspondences, these were overshadowed by vitriolic, abusive, often hilariously absurd or bemusing replies, including various innovative suggestions of how my clearly disturbed mind and body should be removed from existence. Hatred poured through the internet to insult the snake in the video. Commenters offered unhelpful suggestions into how they would have dealt with the situation, some involving retrieving the cat’s corpse from the dead snake after dispatching it in some cruel method or another, often simply resorting to firearms. Others even felt it necessary to call and discuss their deeply felt convictions with me. I remain fascinated at how much antipathy was generated by what is, by all accounts, a fairly normal occurrence in Australia (1, 2).

Of course, such a response is not entirely surprising. Cats are, after all, one of the world’s oldest and most beloved pets. ‘Cat’ is in fact one of the first hundred words that most children learn, and while more households in the US are dog owners, more pet cats in total are owned (around 90 million in the US alone) due to their smaller size, cost, and self-sufficiency (3,4). They provide joy and comfort to countless people around the world, and their companionship role in animal-assisted therapy is something that many people will attest to, elderly schizophrenia patients for example showing improved patient contact, communication, independent self-care, and more (5). This utility as a “modeling companion” for elderly schizophrenics exemplifies just how strong our association with these fascinating animals can be. As such, it is a difficult conversation and the source of significant cognitive dissonance when people, particularly young animal enthusiasts, are confronted with the reality of global introduced species, including feral cats.

While only a foggy childhood memory, I can personally recall the difficulty of learning in the early 1990s that cats are the source of much suffering to native animals around the country and globally. I wouldn’t believe it at first. What, surely not my cat as well? Absolutely yes, in fact we practically ensured it. Being newcomers to the country ourselves, barely speaking English, and knowing little about Australia’s delicate ecosystems, we let her roam freely with little more than a bell collar. She one day abandoned us completely, never to be seen again. To my ongoing shame, our ignorance certainly caused the demise of many native animals living in the nearby national parks of outer north-east Melbourne. Whoever said ignorance is bliss was an ignorant twat, just like I was.

Many years of self-deprecation later, the issue of feral cats is still at the forefront of the conservation movement in Australia (6). Feral populations have continued to grow and put increasing pressure on native animals. The push from environmentalists to control feral cats is also growing fast, particularly in Australia where the issue receives some media attention, although many vocal cat enthusiasts are naturally concerned with what they see as an animal rights issue. A quick internet search shows how much disagreement exists, where even simple suggestions such as keeping cats indoors or enclosed in outdoor ‘cat-runs’ may be dismissed as unhealthy or inhumane to such noble and free spirited animals. Conversely, many cat owners, animal ethics or pet associations such as PETA, suggest it’s crueler to leave domesticated cats outside exposed to diseases, predators, vehicles, or even unscrupulous cat-hating humans. While the vast majority of cat owners are caring people who truly love animals and can appreciate the difficulties of balancing wildlife conservation with society’s needs, the outraged multitudes online and those responding to our video show just how entrenched some opinions are. With many extinctions already attributed to feral cats in Australia in a rather short time period, a resolution is urgently needed to this contentious issue. Though one cannot hope to truly solve the feral cat problem from an armchair, we may at least explore some of the natural history of cats and wildlife in Australia, in the hope that a better understanding of the problems might illuminate, if not a solution, at least some common ground to walk on.

Evolving from the wildcat Felis silvesteris, one of the 38 species in the well known Felidae cat family, the domestic cat F. catus was likely a fantastic aid in rodent control to early agriculturalists, eventually becoming a somewhat more domesticated house pet. Most of us are quite familiar with the ancient Egyptian depictions of cats as house companions, omens, or even various powerful deities. Enigmatic feline-like hieroglyphs and images from around 2500 BC show just how long humans and cats have been associating, however the history of domestic cats goes back further. The oldest archeological evidence for domestication was found in Cyprus, with a cat skeleton found buried a mere 40cm from human remains, dated to some 10,000 years before present (YBP here on) , much earlier than the predicted Egyptian origins (7). This finding was further supported by Driscol et al. (8) who found genetic evidence that all domestic cats originated in the Fertile Crescent. Quoting the authors directly, “…the world’s domestic cats carried genotypes that differentiated them from all local wildcats except those from the Near East…” suggesting domestic cats are directly descended from the Near Eastern Wildcat (F. silvestris lybica). Domestication likely began up to 12,000 YBP, much sooner than dogs at around 17,000 YBP, coinciding with the beginnings of agricultural settlement of the Fertile Crescent and the Middle East, supporting the idea of domestication initially for rodent control followed by companionship.

Domestic cats and humans nowadays seem to get along as companions rather well, aside from the occasional shattered glass. This was unfortunately not always the case. While worshipped in Egypt for thousands of years, the Middle Ages were a bad time to be a cat. Seen as everything from witches in guise, dark omens of the future, or even the Devil himself, cats were persecuted by the public in horrendous fashion. Eighteenth Century Europe was in fact no better, with cats often treated as scapegoats, bearing much of the brunt for the lower class’ hatred for the bourgeoisie, or even tortured and killed on mass for cultural and ceremonial purposes (for a rather gruesome account, and more on the life of the common man in Eighteenth Century France, see (9) the Great Cat Massacre). Although thankfully no longer accepted by society the way it was only a few hundred years ago, unspeakable acts of cruelty are still unfortunately visited upon cats by people, even in our more pet-centric times with animal ethics legislation and heavy penalties in place to prevent such despicable acts.

Like much of the world, many Australians share a strong affection for our feline companions. In 2007, Australians spent over 1.3 billion dollars on caring for over 2.2 billion pet cats (10). While they have been spread around the world by humans for the last 2000 years as either shipboard rodent control, companionship, or even as food, cats arrived in Australia more recently, alongside the European invasion during the late Eighteenth Century (See 11 for an overview of feral cats in Australia). Generally kept aboard transport vessels for rodent control, later in settlements for companionship, these original invaders caused havoc wherever they went, particularly on islands where small, isolated populations had few natural predators and haven’t the necessary adaptation to avoid such skilled hunters. Furthermore, cats are a placental mammal in the order Carnivora, the only one present in Australia aside from the dingo. Australia’s native predators are generally small to medium sized marsupials, reptiles, and birds of prey, all with lower resource requirements and, to be honest, smaller brains in general. Cats are simply too adaptive for native prey compared to their usual suite of predators, and likely outcompete many of our native predators in keeping up with their higher fuel requirements, particularly medium sized marsupials like the Quolls (Dasyurus spp). The situation was not improved by deliberate releases of thousands of cats in the nineteenth century around settlements and goldmines to control introduced mice and rabbits as well as native bush rats. These secondary introductions almost certainly bolstered the genetic diversity of the already present feral cat populations, increasing their adaptive potential.

Unfortunately for everyone, our ecosystems are suffering from the massive presence of feral cats, now completely wild self-sustaining populations which have little contact with humans. Estimates range up to 20 million running around Australia’s wild areas after only a few  hundred years since colonial Europeans invaded the shores, and considering these ultimately innocent cats consume five native animals on average per hunt, the sheer numeric impact of feeding alone on native animals every night is staggering (11, 12). Australian ecosystems are particularly vulnerable due to several variables such as our generally low nitrogen economy soils, thus more of our fauna lean towards what biologists call ‘K-selected’ life strategies. This means slow growing, more efficient animals, with smaller amounts of offspring but generally greater resource investment in each breeding (K for populations where limitations in some variable or resource means populations are close to carrying capacity, r for rate of reproduction where populations have expendable resources and operate at close to their maximum intrinsic reproductive capacity, see (12) for further discussion on K/r selection). One might say K-selected fauna prefer the slow and steady approach, as opposed to r-selected fauna like rabbits which live life in the fast lane, burning though abundant food resources to have as many offspring as possible, as often as possible, in a short life.

While no specific agreement has been arranged between prey and predators, adaptive selection favours K-selected life strategies in resource poor environments. Theoretically, r-selected predators would, in a low resource economy, eventually tax struggling prey populations to the limit and lower numbers, decreasing the health and fitness of both parties. Due to this new resource boundary (prey numbers), natural selection over time favours those heritable mutations which subtly mitigate the impact of the hunters, perhaps by promoting larger, slower growing, later maturing individuals and increasing investment in more moderate sized, less frequent litters. Such limitations eventually lead to healthy ecosystems with a balance between prey populations and predation rates. This selective feedback has been going on in Australia for millennia, through slowly fluctuating environmental conditions, leading to a vast diversity of specialized but very sensitive species and ecosystems. Our fauna communities are dominated by resource efficient reptiles and marsupials (though there are of course exceptions to the rule). Like the majority of non-native domestic animals brought to Australia, cats are placental mammals and are generally more r-selected than our native marsupials. Though Australia has also evolved r-selected species under certain conditions, introduced species don’t share the millions of years of co-adaptation of native plant, animal, and microbe communities.  Our delicate but highly diverse and ephemerally abundant continental ecosystem would have the appearance of a snacking tour to a moderate sized, intelligent, adaptive, fast reproducing mammalian predator.

This disparity in life strategies with our native predators goes some way to explain the successful invasion and heavy impact of feral cats. While these feral populations are already self sustaining into the foreseeable future, gene flow and genomic introgression between ferals and domestics indicates that recruitment and breeding with domestic cats further bolsters wild populations (13). Unfortunately, with few appreciable borders for cats across this large and, for us primates, inhospitable continent, the total size and growth rate of wild Australian populations are extremely hard to accurately quantify, though the aforementioned figure of  20 million is certainly plausible (12). Feral cats appear to use a facultative prey choice strategy, targeting invasive rabbits initially, quickly switching to a wide variety of animals when this ideal prey is unavailable (14). On average, they may take five native animals a night. Considering this, the potential predatory impact could be well over of 20 billion native animals each year, a much higher figure than many might suspect.

How much of an impact can cats truly have? Dickman et al. 1996, by determining what ecological characteristics make a species vulnerable (factors such as mobility, fecundity, feral cat density in habitats, anti-predatory behaviours, size, and many more) then assessing how many risk-attributes a species possesses, demonstrated that 81 endangered and vulnerable species are likely at risk from feral cat impacts, however more observations are needed to fully verify these numbers. Recent studies of the impacts of cats have taken several approaches; surveying cat owners for the kills their pets return can give some indication of cat predation, perhaps even prey selection behaviour, however these estimates are obviously limited to domestics, and by various “detection biases” such as the fact that only around 20% of prey are presented to the owners while the rest are either eaten or discarded (15, 16). Camera traps or mounted cameras give more direct confirmation of predatory behaviors/rates, however these methods still often rely on many assumptions (16, 17). Extrapolating feral cat population and predation rates from trap samples is one thing but, while naturally informative, these numbers themselves tell us little of the actual causal link between cats and declines in native communities (15, 17). Studies of feeding ecology through examining the stomach contents of feral cats are excellent and with enough data can give good baseline estimates of impacts, however we still have to extrapolate from what samples are available, and any initial error in our assumptions increases with our extrapolation. So while counts of prey items are a valuable resource, even these estimates must be treated with caution (see Section 4.2 of Dickman, 1996, for an overview of feral cat diet studies in Australia).

Much better, then, to study the response of prey populations under different predation pressures from cats. This might, for example, involve studying distinctly separate communities of native wildlife under varying feral cat populations. Alternatively, one might enclose large patches of native landscape with predator proof fencing and eliminate cats within these habitats, with the outside as an effective control patch where feral cats remain present. This latter method was recently undertaken at the World Heritage Listed Kakadu National Park in the Northern Territory. Working with the NT Department of Land and Resource Management alongside Parks Australia, ecologist Daniel Stokeld and others recently reported that faunal biodiversity, but particularly reptiles, increased significantly in response to cat exclusion.

“We were quite surprised by the response of reptile numbers and diversity,” said Stokeld, speaking to ABCs AM Radio Show, “That was something that hasn’t been shown in other studies. So that was quite a significant finding signifying that cats are having quite an impact on reptile populations.” (See 6 for a link to the article and radio podcast)

The NT Government’s Director of Terrestrial Ecosystems, Dr Graeme Gillespie, further noted that despite various reptiles frequently turning up inside the stomach contents of feral cats, this is the first hard evidence of an ecologically significant impact in Northern Australia. Reptile abundance and reptile species richness within the excluded zones effectively doubled within two years. To quote Dr. Gillespie,

“That’s a very, very fast recovery, so that means the cats are having a very big influence on the number and diversity of reptiles that are out there, in particular in areas like Kakadu National Park.”

Unfortunately, very few small mammals were detected in their dataset, and with such a small sample size no reliable conclusions could be made for mammals in this particular study. One might be tempted to speculate that prior to feral cat impacts this problem of sample sizes in small mammals may have been a non-issue.

The Australian Wildlife Conservancy, a phenomenal non-profit, conservation organization, and a significant contributor to The Action Plan for Australian Mammals (12), outline the cat crisis rather succinctly on their website. Emphasizing that with 29 extinctions since white man arrived on these shores we’ve lost almost 10% of our Australian mammals. This is the highest mammal extinction rate in the world. A further 30% of our remaining mammals are currently threatened with extinction in the near future, with cats representing a major threat. I suppose with the new data from the Northern Territory we can now add threatened reptiles to the list of potential victims. Birds, of course, also suffer heavily, even from our domestic cats, leading to urban areas acting as ‘population sinks’ for native birds, actively lowering numbers in adjacent habitat stands (18). While generally a fan of prey around 200grams in weight, large feral cats can take kills of up to 2kg, securing prey with teeth and forelimbs while the rear legs tear at the flanks and body (Dickman et al. 1996). It seems that feral cats negatively impact a broad range of native wildlife, from tiny invertebrates to medium sized mammals, reptiles and birds, and while mammalian prey are generally preferred, their facultative feeding strategy means when scarce they will happily switch prey items.

These studies and more indicate a clear need for decisive action in controlling feral cats. Three methods are typically employed in cat eradication; shooting, trapping, or baiting (19). While trapping might seem like the easiest option, the amount of field effort required in transport, trap installation, monitoring etc. are rather substantial, all the more when working with a live trap and a large, distressed feral animal in a field setting. Shooting has traditionally been preferred and while seemingly a rather gruesome solution, it is arguably more humane than hours of trap stress. However this still requires a substantial amount of man hours and, due to their adaptive intelligent nature, cats have been known to become wary if the shooter happens to miss his mark. Baiting with 1080 and PAPP are generally considered the cheapest, most cost efficient methods. However, negative public perception is a continuous issue, with no effective treatment for accidental poisoning and other animal welfare concerns,  although new baits, poisons, and techniques are in constant development, such as the Eradicat bait developed by the State of Western Australia Department of Parks and Wildlife in 2014 (20).

With a continent worth of feral cats to control, no doubt cost effectiveness must play a significant role in any measures used in this battle. It’s also imperative that all efforts are made to minimize any collateral damage to wildlife, such as native predators accidentally taking baits meant for ferals, with consideration of the welfare of target pest species. Previous attempts have involved various bait modifications, for example changing the scent profile or adding insecticides to mitigate breakdown of the bait by invertebrates and subsequent uptake by insectivorous native predators (20). These still rely on the animal ingesting the toxin somehow, however the latest high-tech tool involves a rather ingenious method to achieve toxin intake, capitalizing on a thorough understanding of differences in cat and native mammal ecology, lasers, and a pressurized squirt gun.

Relying on the cat’s particular penchant for hygiene and grooming, these so called “grooming traps” combine the best of all three control methods while avoiding many of the pitfalls (21). They involve a mechanized, pressurized spray gun installed alongside infra-red laser detectors, assembled into a single, field-ready trap unit. Calibrated to fire only when the target animals size and dimensions, particularly the space underneath the trunk of the body (between fore- and hind limbs) matches that of a cat and not a native animal, the trap fires a dose of adherent toxic gel between the shoulders of the targeted cat which, unlike our native animals, will fastidiously lick off the toxin within a few minutes. This allows a targeted, species specific delivery of a lethal dose of PAPP, the biological action of which the RSPCA has approved as significantly more humane than 1080, acting as a sedative first, leading to unconsciousness and a pain-free death soon after. After seven years of research and development by Mr John Read, an ecologist from the University of Adelaide, these incredible multi-faceted techno-traps are currently being trialed on the Pullen Pullen Reserve in western Queensland, purchased by Bush Heritage Australia (22). The 56,000ha conservation reserve is home to the endangered Night Parrot (Pezoporus occidentalis) thought to be extinct for over 100 years until the 1990’s. With the first traps going live earlier this month, many scientists are certainly eager to see the results, as any potential solutions or new tools in this epic losing battle for biodiversity would be rather welcome.

While all this sounds rather promising, there are still numerous challenges to solving the cat crisis in Australia. Even if these new generations of control techniques prove to be cost effective in controlling cats, public perceptions of feral cat control are still often negative. Many promote the Trap-Neuter-Release (TNR) method of eliminating cat populations, as this involves de-sexing rather than killing (see 23 for details on TNR for feral cats from the RSPCA). However the massive costs associated with trapping/desexing adults, re-homing kittens and socialized adults, and euthanizing old or sick cats are very difficult to justify, particularly considering that even a neutered animal still needs to hunt as long as it lives if returned to the wild.

Many refuse to accept that cat control is a necessary evil, and a responsibility we as humans should take very seriously. This was most apparent in 2015 when, in response to the Action Plan for Australian Mammals (12), the Australian Government announced a planned cull of 2 million feral cats over the next few years (10% of the estimated population) using trapping, shooting, and poison baits (24). Animal culls generally succeed in raising the ire of the animal welfare minded, and this was no different. Culling is an important tool in wildlife management, but is often regarded as inhumane, particularly when used on native populations. This is not the case with cats, yet still the opposition to was extremely vocal. The most prominent response came in the form of an open letter to our Environment Minister from classical French actress Brigitte Bardot, as well as an online post from Stephen Patrick Morrissey, lead vocalist for 80’s indie rock band The Smiths. Both wrote statements to the minister in response to the announced culling plans, with Morrissey making the visibly false claim that feral cats are “2 million smaller versions of Cecil The Lion”, while Ms Bardot’s much longer open letter suggested a TNR program would be more effective, humane, and less harmful to the environment since poisons would not be released, and sterilized cats would hold territory but not breed.

These statements are both wildly inaccurate. Ms Bardot’s claim that TNR campaigns are effective “everywhere” is a standard denialist position (only a Sith deals in absolutes), completely ignoring scientific evidence. Little effort is needed to find that the claims made by TNR advocates, such as that cats only negatively impact island populations not large continents, or that they don’t cause native species declines at all, or they are filling some required natural niche, and many others, are all contradicted in scientific literature by numerous authors and sources (see (26) for just one of many papers dismissing TNR). There is no excuse for such ignorance when one purports to be an animal welfare activist; science must be your guiding light. The stakes are too high, and while the public image of a pop-culture icon saving our animals is naturally appealing, it is important to remember that such advocates are not scientists and if they refuse to accept scientific conclusions, their opinion on wildlife science should be ignored. Furthermore, while we’re here dismissing the ignorant, anyone willing to accept the opinions of Ms Bardot as somehow valuable may want to read her thoughts on race relations, homosexuality, school teachers, the poor, immigration, and how the future of France might be improved by returning the public guillotine from retirement (27). This is the same ‘animal activist’ who was taken to court when in the 80’s she had her neighbour’s donkey castrated for making advances on her own donkey, which she considered “sexual harassment” (28).  Perhaps we can find better role models for animal rights and conservation than these two.

Many well meaning folks perhaps do not fully understand the true extent of the feral cat crisis or the sensitivity of our ecosystems. Additionally, it seems that for some people, no matter the costs to our native wildlife, cats (and cats alone, not foxes, rabbits, or,  perish the thought, the invasive cane toad Rhinella marina) are simply more deserving of protection and existence due to their value as human companions and for our emotional ties with these beautiful animals (29). One is tempted to assume this attitude is also a result of simple ignorance, an under appreciation of our endemic and unique fauna communities. If this is so, as appears to currently be the case, a broad, environmental education approach that improves local stakeholders’ ecological understanding is more likely to succeed than informing cat owners and locals about cat impacts alone (30). The government’s response to Morrissey and Bardot’s comments, in the form of open letters from Threatened Species Commissioner Gregory Andrews (31, 32), attempts to achieve this by publically laying out the basic framework of Australia’s cat crisis and why it is essential to implement a lethal control program as soon as we can, addressing such issues as welfare, effectiveness and cost.

Let’s hope it doesn’t fall upon deaf ears, after all it is we humans, not cats themselves that caused this catastrophe (couldn’t help myself, please don’t judge too harshly for this one terrible, terrible pun!) and to ignore the consequences and current declines in native species across the continent would be disastrous. Invasive species are a major driver of global extinctions, just behind habitat destruction, sometimes even the leading cause, as is the case with bird extinctions (33). To not have a heavy handed response to this crisis would be to condemn millions of native animals each night. It would assert that cats have more right to existence than other animals due to our own affections. And finally, it would have us shy away from our mistakes, rather than learning from our many and varied short-comings, as is the general tendency of human history. I find this unacceptable, the result of ignorance and fear, not knowledge and compassion.

May our efforts to repair our mistakes and contain the Australian feral cat crisis not be in vain. On that note, I leave you with the borrowed final words of a more eloquent human than I; words which I feel suitably match my own hopes and dreams for this beautiful, unique landscape, despite the various charges underneath our watch who are slowly slipping away into extinction, forever, unless we act.

“For the moment, I hope that Australasians one and all will begin to ask the right questions. For this is the first, necessarily wobbly step on the road to discovering what it means to be custodians of the wonderful and enigmatic ‘new’ lands”

– Tim Flannery, The Future Eaters.

 

References

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2. brisbanetimes.com.au/queensland/five-cats-eaten-by-pythons-in-one-month-in-cairns-20160203-gmkkm4.html
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14. Doherty, T.S., Davis, R.A., Van Etten, E.J.B., Algar, D., Collier, N. , Dickman, C.R., Edwards, G., Masters, P., Palmer, R., Robinson, S. (2015) A continental-scale analysis of feral cat diet in Australia. Journal of Biogeography 42.
15. Barratt, D.G., 1998. Predation by house cats, Felis catus (L.), in Canberra, Australia. II. Factors affecting the amount of prey caught and estimates of the impact on wildlife. Wildl. Res. 25, 475–487.
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17. Meek, P., Ballard, G., Fleming, P., Falzon, G. (2016) Are we getting the full picture? Animal responses to camera traps and implications for predator studies. Ecol Evol. 10.
18. Van Heezik, Y., Smyth, A. Adams, A., Gordon, J. (2010) Do domestic cats impose an unsustainable harvest on urban bird populations? Biological Conservation. Volume 143, Issue 1.
19. Environment Australia, 2008. Threat Abatement Plan for Predation by Feral Cats. Environment Australia, Biodiversity Group, Canberra.
20. Fisher, P., Algar, D., Murphy, E., Johnston, M., Eason, C. (2014) How does cat behaviour influence the development and implementation of monitoring techniques and lethal control methods for feral cats? Appl. Anim. Behav. Sci.
21. Read, J.L. (2010) Can fastidiousness kill the cat? The potential for target-specific poisoning of feral cats through oral grooming. Ecological Management & Restoration. Vol 11, 3.
22. theguardian.com/environment/2016/apr/17/robots-lasers-poison-the-high-tech-bid-to-cull-wild-cats-in-the-outback
23. rspca.org.au/What-is-trap-neuter-return-and-is-it-an-appropriate-strategy-for-the-management-of-unowned-cats_462.html
24. theaustralian.com.au/national-affairs/greg-hunt-calls-for-eradication-of-feral-cats-that-kill-75m-animals-a-night/story-fn59niix-1226939644027
25. true-to-you.net/morrissey_news_150828_01
26. Longcorem T., Rich, C., Sullivan, L.M. (2009) Critical Assessment of Claims Regarding Management of Feral Cats by Trap–Neuter–Return. Conservation Biology, Volume 23, No. 4.
27. theguardian.com/world/2003/may/15/france.davidhearst
28. latimes.com/1989-12-04/news/vw-298_1_brigitte-bardot
29. Wald, D.M., Jacobson, S.K., Levy, J.K. (2013) Outdoor cats: Identifying differences between stakeholder beliefs, perceived impacts, risk and management. Biological Conservation. 167.
30. Dombrosky J, Wolverton S 2014TNR and conservation on a university campus: a political ecological perspectivePeerJ 2e312
31. environment.gov.au/system/files/resources/8bde0309-4f18-4bab-bda8-fc3d78bb5c75/files/steven-morrissey-response.pdf
32. theguardian.com/world/2015/oct/14/australia-writes-morrissey-brigitte-bardot-defend-cull-feral-catsTRENDS in Ecology and Evolution Vol.20 No.3
33. Gurevitch, J., & Padilla, D.K. (2004) Are invasive species a major cause of extinctions? TRENDS in Ecology and Evolution Vol.19 No.9

And just in case I haven’t got enough mail yet, here’s that video 🙂 Enjoy!