Pet cats in Britain’s suburbs may be killing up to 270 million animals per year, a study suggests.
Suburban cats living on the edge of natural areas kill an average of 34 animals each per year, according to the research.
Those living in suburbs but surrounded by other houses and further from natural habitats killed an average of 15 each.
Cats in both types of areas killed similar amounts of birds, but those on the edge of the green spaces killed more mammals, the researchers from the University of Reading and Royal Holloway University of London discovered
Cats in both types of areas killed similar amounts of birds, but those on the edge of the green spaces killed more mammals, the researchers from the University of Reading and Royal Holloway University of London discovered.
In terms of the types of birds killed, the cats with easy access to the natural land killed far more robins, while the others killed far more blackbirds.
Wearing a bell was no deterrent, with these cats actually bringing home the most prey, the study found.
Dr Rebecca Thomas, from Royal Holloway University of London, who was part of the research team said: ‘They are a non-native species.
‘They reach incredibly – and unnaturally – high densities, especially in suburban environments.
‘They get fed by their owners and given veterinary care so you could consider them mini super predators.’
There are an estimated 9.5 million owned pet cats in Britain, the study stated.
And it is not just the direct killing of prey that is the issue, said the lead author of the study Dr Tara Pirie, who is now based at the University of Surrey.
The mere presence of cats in an area can have what is known as a ‘sub-lethal fear effect’ which then has consequences for animal numbers down the line.
‘Just the presence of a predator can cause wildlife to change their behaviour either reducing feeding through heightened vigilance or staying away from a nest leaving it exposed, for example,’ said Dr Pirie.
‘This can reduce the survival of both adults and offspring.
‘Cats can also carry diseases such as Toxoplasma gondii which can be transmitted to wildlife, again reducing their survival rate.’
For the study, published in the journal Landscape and Urban Planning, the team tracked the movements and amount of prey brought home by 79 cats living across Berkshire and Hampshire, over a period of a year.
They compared the predation rates of those living within 100metres of natural land and those living around 1 kilometre from it.
The pets near the natural land ventured an average of 3.42 hectares around their home, while the others roamed in 2.01ha.
‘A simple extrapolation based on the predation rates found in this study suggests that the 9.5million pet cats in Great Britain may kill in the region of 160-270 million prey individuals per year,’ the team wrote in their research paper.
They added: ‘Domestic cats bring great joy and companionship to their owners, with benefits for mental health and well-being.
‘But they also cause the loss of tens of millions of animals each year through predation, which in some cases may go beyond animal welfare concerns and become conservation concerns.
‘It is only by understanding the possible negative ecological effects pet cats may be exerting on their local biodiversity that we can begin to develop appropriate approaches to environmentally-sensitive cat ownership.’
Dr Pirie said that previous research had found that bell-wearing did help reduce killing and that it may be that the cats in their study were ‘very good hunters and the owners had put a device on because they were aware of it’.
But giving more food in the hope that filling them up will prevent hunting is unlikely to help.
‘As our research and other research suggest, leaving food out does not appear to reduce prey returns,’ she said.
‘This does make sense because cats are intrigued by movement – think of a cat playing with a toy – and it could be the movement of prey that simply triggers the hunting behaviour of the cat.’