Feral cats are an invasive species in Australia. Because they are not native to Australia and were only introduced by European colonists as pets in the early 1800s, native Australian animals did not co-evolve with them.[1] As of 2016, some 3.8 million domestic cats and up to 6.3 million feral cats continue to live in Australia.[2][3]

A taxidermy feral cat with a Major Mitchell's cockatoo at the Central Australian Museum

The Invasive Species Council has estimated that each year domestic and feral cats in Australia kill 1.5 billion mammals, 399 million birds, 609 million reptiles, 93 million frogs, and 1.1 billion invertebrates.[4] As one of the most ecologically damaging and the most costly invasive species in Australia, predation by both domestic and feral cats has played a role in the extinction of many of Australia's indigenous animals. For instance, cats are found to have significantly contributed to the extinction of at least 22 endemic Australian mammals since the arrival of Europeans.[5]

For biosecurity reasons, any cats that are imported into Australia must meet conditions set by the Department of Agriculture, Fisheries and Forestry.

Historical context

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Historical records date the introduction of cats by the first settlers in 1788 and that cats first became feral around Sydney by 1820.[6] In the early 1900s concern was expressed at the pervasiveness of the cat problem.[7]

Domesticated cats

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Many pet cat owners in Australia let their cats outside at night.[8]

Each pet cat in Australia kills an estimated 110 native animals each year; totalling up to about 80 million native birds, 67 million native mammals and 83 million native reptiles being killed by them annually.[8]

Almost 30% of Australian households keep at least one domesticated cat.[9][2] Domesticated cats must be microchipped in every state of Australia except Tasmania.[10] All pet cats past six months of age must be desexed in the Australian Capital Territory, Tasmania, South Australia and Western Australia.[11]

Feral cats

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Feral cats are wild-born descendants of domesticated cats.

Ecological damage

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Feral cats are a major invasive species and have been linked to the decline and extinction of various native animals in Australia. They have been shown to cause a significant impact on ground-nesting birds and small native mammals.[12] A study in the 2010s estimated that each feral cat kills 740 wild animals per year.[13] Feral cats have also hampered attempts to reintroduce threatened species back into areas where they have become extinct, as the cats quickly kill the newly released animals.[14] Environmentalists conclude that feral cats have been an ecological disaster in Australia, inhabiting almost all of its ecosystems, and being implicated in the extinction of several marsupial and placental mammal species.[15][16]

A field experiment conducted in Heirisson Prong (Western Australia) compared small mammal populations in areas cleared of both foxes and cats, of foxes only, and a control plot. Researchers found the first solid evidence that predation by feral cats can cause a decline in native mammals. It also indicates that cat predation is especially severe when fox numbers have been reduced.[17] Cats may play a role in Australia's altered ecosystems; with foxes they may be controlling introduced rabbits, particularly in arid areas, which themselves cause ecological damage. Cats are believed to have been a factor in the extinction of the only mainland bird species to be lost since European settlement, the paradise parrot.[18] Cats in Australia have no natural predators except dingoes and wedge-tailed eagles, and as a result, they are apex predators where neither the dingo nor the eagle exists.[19] Also, dingos do not appear to affect the activity of cats.[20]

Claimed benefits

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Some researchers argue that feral cats may suppress and control the number of rats and rabbits, and cat eradication may damage native species indirectly.[21][22]

Economic impacts

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Cats are the costliest invasive species in Australia.[23] The cost of invasive cats to the national economy is estimated to be nearly A$19 billion over the 60 years up to 2021, with most of the cost spent on population control. This cost significantly outstrips the next most costly invasive species, with rabbits in Australia coming in at nearly A$2 billion.[24]

Control

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Pintupi, Nyirripi and other Western Desert peoples in Western Australia and Northern Territory have been hunting cats to use as a food source and for bush medicine for decades, but in 2015 they were also participating in a program with ecologists to help monitor and reduce cat predation on threatened species.[25]

Some varmint hunters of feral cats in Australia, such as Barry Green, face backlash and even death threats for the culling of the invasive species.[26][27]

Since 2016, a program on Kangaroo Island aims to fully eradicate the island's feral cat population, estimated at between 3000 and 5000, by 2030.[28][29] The 2019–2020 bushfires have complicated the eradication efforts, as the gradual regrowth of the burnt brush creates favourable conditions for cat breeding and makes them more difficult to hunt.[30] By the end of 2021, at least 850 cats had been removed from the burnt area at the western end of the island using grooming traps with state-of-the-art technology[31] and cameras. In addition, an exclusion fence had been built on private property around some of the burnt land, helping to protect the populations of Kangaroo Island dunnart and southern brown bandicoot.[32]

Phantom cats

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The numerous sightings of phantom cats in Australia include the Gippsland phantom cat and the Blue Mountains panther.[33]

Australian folklore holds that some feral cats have grown so large as to cause inexperienced observers to claim sightings of cougars in Western Australia. While this rarely occurs in reality, large specimens are occasionally found, and perspective can make these specimens larger than they actually are. The big cat sightings may be zoo escapees or exotic pets on the loose.

See also

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References

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  1. ^ "Cute killers: Cats kill more than 1.5 billion Australian native animals a year". www.cdu.edu.au. Retrieved 12 January 2021.
  2. ^ a b "Pet Ownership in Australia 2016" (PDF). AnimalMedicinesAustralia.org.au. Animal Medicines Australia. 2016. Archived from the original (PDF) on 29 October 2018.
  3. ^ Legge, S.; Murphy, B.P.; McGregor, H.; Woinarski, J.C.Z.; Augusteyn, J.; Ballard, G.; Baseler, M.; Buckmaster, T.; Dickman, C.R.; Doherty, T.; Edwards, G.; Eyre, T.; Fancourt, B.A.; Ferguson, D.; Forsyth, D.M.; Geary, W.L.; Gentle, M.; Gillespie, G.; Greenwood, L.; Hohnen, R.; Hume, S.; Johnson, C.N.; Maxwell, M.; McDonald, P.J.; Morris, K.; Moseby, K.; Newsome, T.; Nimmo, D.; Paltridge, R.; Ramsey, D.; Read, J.; Rendall, A.; Rich, M.; Ritchie, E.; Rowland, J.; Short, J.; Stokeld, D.; Sutherland, D.R.; Wayne, A.F.; Woodford, L.; Zewe, F. (February 2017). "Enumerating a continental-scale threat: How many feral cats are in Australia?". Biological Conservation. 206: 293–303. doi:10.1016/j.biocon.2016.11.032.
  4. ^ "Cats in Australia". Retrieved 18 September 2023.
  5. ^ Aguirre, Jessica Camille (25 April 2019). "Australia Is Deadly Serious About Killing Millions of Cats". The New York Times. ISSN 0362-4331. Retrieved 10 January 2021.
  6. ^ Abbott, Ian (2008). "Origin and spread of the cat, Felis catus, on mainland Australia: Re-examination of the current conceptual model with additional information" (PDF). Conservation Science Western Australia Journal (7). Archived from the original (PDF) on 4 March 2023. Retrieved 29 May 2022.
  7. ^ "The Cat Problem in Australia". The Sunday Times. Perth, Western Australia: National Library of Australia. 22 December 1912. Christmas Number, 3rd section, p. 8. Retrieved 21 January 2016.
  8. ^ a b Readfearn, Graham (15 May 2020). "Keep pet cats indoors, say researchers who found they kill 230m native Australian animals each year". The Guardian. Retrieved 4 July 2022.
  9. ^ "Pets in Australia: A national survey of pets and people" (PDF). AnimalMedicinesAustralia.org.au. Animal Medicines Australia. October 2019.
  10. ^ "Responsible Pet Ownership: Microchipping". RSPCA.org.au.
  11. ^ "Is desexing mandatory for cats and dogs?". KB.RSPCA.org.au. 16 May 2019. Retrieved 4 July 2022.
  12. ^ Dickman, Chris (May 1996). Overview of the Impacts of Feral Cats on Australian Native Fauna (PDF). National Parks and Wildlife, Australian Nature Conservation Agency, Institute of Wildlife Research. ISBN 0-642-21379-8. Archived from the original (PDF) on 4 March 2016. Retrieved 11 February 2013.
  13. ^ "Feral and pet cats killing 'billions' of native animals each year, research finds". ABC.net.au. 14 July 2019. Retrieved 12 January 2021.
  14. ^ The Threat Of FeralCats
  15. ^ Robley, A.; Reddiex, B.; Arthur, T.; Pech, R.; Forsyth, D. (September 2004). Interactions between feral cats, foxes, native carnivores, and rabbits in Australia (PDF). Arthur Rylah Institute for Environmental Research. Archived from the original (PDF) on 17 March 2011. Retrieved 12 February 2013.
  16. ^ Davies, Wally; Prentice, Ralph (March 1980). "The feral cat in Australia". Wildlife in Australia. 17: 20–26, 32. Retrieved 21 January 2016.
  17. ^ Risbey, Danielle A.; Calver, Michael C.; Short, Jeff; Bradley, J. Stuart; Wright, Ian W. (2000). "The impact of cats and foxes on the small vertebrate fauna of Heirisson Prong, Western Australia. II. A field experiment". Wildlife Research. 27 (3): 223. doi:10.1071/WR98092.
  18. ^ "Psephotus pulcherrimus — Paradise Parrot". Department of Sustainability, Environment, Water, Population and Communities. 13 March 2012. Retrieved 14 February 2013.
  19. ^ Moseby, Katherine E.; Neilly, Heather; Read, John L.; Crisp, Helen A. (2012). "Interactions between a Top Order Predator and Exotic Mesopredators in the Australian Rangelands". International Journal of Ecology. 2012. Hindawi Limited: 1–15. doi:10.1155/2012/250352. hdl:2440/77850. ISSN 1687-9708.
  20. ^ Fancourt, Bronwyn A.; Cremasco, Peter; Wilson, Cameron; Gentle, Matthew N. (16 October 2019). "Do introduced apex predators suppress introduced mesopredators? A multiscale spatiotemporal study of dingoes and feral cats in Australia suggests not". Journal of Applied Ecology. 56 (12). Wiley: 2584–2595. doi:10.1111/1365-2664.13514. ISSN 0021-8901.
  21. ^ Arian D. Wallach, 2014, Wild cat Archived 28 January 2021 at the Wayback Machine, Dingo for Biodiversity Project
  22. ^ Dana M. Bergstrom, Arko Lucieer, Kate Kiefer, Jane Wasley, Lee Belbin, Tore K. Pedersen, Steven L. Chown, 2009, Indirect effects of invasive species removal devastate World Heritage Island, Journal of Applied Ecology, 46(1), pp.73 - 81, DOI:10.1111/j.1365-2664.2008.01601.x, British Ecological Society
  23. ^ Bradshaw, C. J.; Hoskins, A. J.; Haubrock, P. J.; Cuthbert, R. N.; Diagne, C.; Leroy, B.; Andrews, L.; Page, B.; Cassey, P.; Sheppard, A. W.; Courchamp, F. (2021). "Detailed assessment of the reported economic costs of invasive species in Australia". NeoBiota. 67 (67): 511–550. doi:10.3897/neobiota.67.58834. S2CID 237262764.
  24. ^ Khan, Jo (29 July 2021). "Invasive species have cost Australia $390 billion in the past 60 years, study shows". ABC News. Australian Broadcasting Corporation. Retrieved 31 July 2021.
  25. ^ Wahlquist, Calla (27 October 2015). "Traditional hunters and western science join forces in the fight against feral cats". The Guardian. Archived from the original on 27 October 2015. Retrieved 17 January 2021.
  26. ^ Shooting Cats: Australia's War on Feral Cats on YouTube
  27. ^ "SA bow hunter receives death threats after sharing images of feral cat cull". Nine News. 25 February 2016. Retrieved 4 July 2022.
  28. ^ "'They're highly evolved predators': Kangaroo Island's plan to be cat-free". Australian Broadcasting Corporation. 6 October 2016.
  29. ^ Kangaroo Island Feral Cat Eradication Program – Landscape South Australia – Kangaroo Island
  30. ^ Campbell, Claire (12 September 2020). "Endangered species 'looking at extinction' on Kangaroo Island as feral cats roam". ABC News. Archived from the original on 13 September 2020. Retrieved 14 January 2021.
  31. ^ Perpitch, Nicolas Felixer grooming trap to be rolled out as part of Australia-first strategy to control feral cats ABC News, 28 June 2023. Retrieved 18 September 2023.
  32. ^ Hughes, Megan (30 December 2021). "Hundreds of feral cats removed from Kangaroo Island in bid to protect endangered native species". ABC (Australian Broadcasting Corporation). Retrieved 4 January 2022.
  33. ^ "Amid sightings and claims of a cover-up, could the Lithgow panther actually exist?". www.abc.net.au. 12 June 2018. Retrieved 28 July 2020.
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