As at May 2021, no study in urban Australia has established that cats have a negative impact on native wildlife populations.
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A 10 year Perth study (Lilith et al 2010) investigated species diversity across three different bushland areas where cats were either:
- required to be inside at night and wear a bell; or
The study found that medium-sized mammals, such as Brush-tailed Possums and Southern Brown Bandicoots, were not impacted by the presence or absence of cats. The smaller Mardo (Antechinus flavipes), which is highly susceptible to cat predation, was in higher numbers in areas where cats were unregulated.
A Perth study found that cat density has no effect on passerine bird populations. Decreasing bird populations were associated with increasing urbanisation and housing density, and increasing distance from bushland. The study concluded that habitat destruction and degradation, rather than cats, were the main factors impacting on birds (Grayson et al 2007).
A Sydney study of nest predation in 24 forest patches in the Sydney metropolitan area found that no nests were attacked by cats (Matthews et al 1999). Black Rats, Ringtail Possums, Antechinus species and other birds were the main predators. Nest predation was reduced when cats were present.
Most of the bird species that cats kill have an average life span of 2-4 years in the wild. This means that 25-50% are dying of other causes every year and would not survive to the next breeding season (Australian Government Department of the Environment and Energy, 2017).
Research also shows that birds caught by cats in urban areas are on average less healthy than birds killed by flying into windows and cars (Baker et al 2008, Møller and Errotzøe 2000). The researchers concluded that most cat-related bird deaths are not additive to the number dying each year.
In the UK, the Royal Society for the Protection of Birds has similarly concluded that there is no scientific evidence that cats are causing bird populations to decline. It also highlights that most birds who were killed by cats would have died from other causes before the next breeding season.
Just as in Australia, UK research has found that declines in bird populations are usually caused by habitat change or loss.
A further study (Franklin et al 2018) found that the main prey items of cats are mice, followed by rats, small lizards, then common species of birds. A Brisbane City Council analysis of the stomach contents of 25 cats found only one species – the Black Rat (Brisbane City Council 2015).
While cats may certainly kill individual native animals, they have not been found to have an overall impact on biodiversity in urban areas.
Desexed cats have reduced energy requirements compared with undesexed animals (Mitsuhashi et al 2011), which may also indirectly reduce wildlife predation.
The principal cause of declining wildlife populations in urban areas is habitat destruction, degradation and fragmentation by humans.
Cats in non-urban areas
Since the federal government launched its so-called ‘war on cats’, it has spent large sums of money funding studies on cats.
Some of these have made estimates of the number of animals cats kill per year throughout Australia (not in urban areas. In urban areas, there is markedly less available habitat, wildlife numbers and species diversity than in the bush).
However, these studies have not determined if this is significant at a population level.
They have also failed to provide any long-term solutions. The only ‘solution’ proposed to date is to kill cats, including through the use of leg-hold traps and 1080 poison.
Australian research has found that killing cats causes a rapid rebound in population (Lazenby et al, 2014).
More research is required to determine how any impact wild cats in non-urban and peri urban areas have on wildlife can be reduced.
1080 is banned in most countries in the world because of the considerable suffering that occurs to any species who ingests a fatal dose.
Contrary to claims by Australian governments and the poisons industry, native animals do die from 1080. It also poisonous to farmed animals, working dogs and companion dogs.
This footage, taken by a farmer who has suffered the deaths of a number of his dogs to 1080, on his own property, shows how they die. (He lives far from a vet and had no gun to shoot the dog. There is no antidote, anyway).
Killing Shroedingers Feral Cat describes the suffering of a cat who had been poisoned by 1080 (Marks C, 2013). Although the scientist does not like cats, he chose to kill the cat rather than continue to witness their suffering.
1080-laced baits are known to be carried by birds such as ravens and dropped onto ‘non-target’ properties, including in farmed animal water troughs.
No property near where 1080 is being used is safe from 1080.
If you are concerned that 1080 is being used near you, you may like to obtain a free 1080 Legal Action Pack. This warns potential poisoners that you will sue should you suffer adverse effects from their use of 1080 near your property. These kits have been successful in preventing governments from using 1080.
So-called ‘soft jaw’ leg hold traps
Authorities and individuals who use so-called soft jaw leg hold traps claim that ‘non-target’ animals can be released from them unharmed.
Watch this video of a soft-jaw trap on a human hand. After carefully closing the trap on their hand, they could withstand the discomfort for all of five minutes 30 seconds.
Imagine what would happen if it had slammed closed on a smaller animal’s leg.
As at 2021 in Victoria Australia, it is legal to force animals to suffer in these traps for three full days (72 hours).
Australian Government, Department of the Environment and Energy. What have we learned from banding studies? http://www.environment.gov.au/science/bird-and-bat-banding/about-banding/banding-studies (accessed 15/12/17).
Baker PJ, Molony SE, Stone E, Cuthill IC, Harris S. Cats about town: is predation by free-ranging pet cats Felis catus likely to affect urban bird populations? Ibis, 2008; 150: 86-99.
Brisbane City Council. The Invasive Times, Issue 4, October 2015-2016
Franklin M, Rand J, Marston L, Morton J. Prey captured by owned cats and dogs in Australia. Animals, 2018
Grayson J, Calver M, Lymbery A. Species richness and community composition of passerine birds in suburban Perth: is predation by pet cats the most important factor? In: Lunney D, Eby P, Hutchings P, Burgin S, editors. Pest or Guest: The Zoology of Overabundance. Royal Zoological Society of New South Wales, Mosman, NSW, Australia, 2007: 195-207.
Lilith M, Calver MC, Garkaklis M. Do cat restrictions lead to increased species diversity or abundance of small and medium sized mammals in remnant urban bushland? Pacific Conservation Biology, 2010: 16(3): 162-72 (accessible at: http://researchrepository.murdoch.edu.au/id/eprint/6221/, accessed 15/12/17).
Marks C, Killing Shroedingers Feral Cat, Animal Studies Journal, 2013, 2(2)
Matthews A, Dickman CR, Major RE. The influence of fragment size and edge on nest predation in urban bushland. Ecography,1999; 22: 349-56.
Mitsuhashi Y, Chamberlin AJ, Bigley KE, Bauer JE. Maintenance energy requirement determination of cats after spaying. Br J Nutr, 2011; 106 suppl: S135-8.
Møller AP, Erritzøe J. Predation against birds with low immunocompetence. Oecologia 2000; 122: 500-4.