Domestic cats hunt wildlife less if owners play with them daily and feed them a meat-rich food, new research shows.
Hunting by cats is a conservation and welfare concern, but methods to reduce this are controversial and often rely on restricting cat behaviour in ways many owners find unacceptable.
The new study - by the University of Exeter - found that introducing a premium commercial food where proteins came from meat reduced the number of prey animals cats brought home by 36%, and also that five to ten minutes of daily play with an owner resulted in a 25% reduction.
"Previous research in this area has focussed on inhibiting cats' ability to hunt, either by keeping them indoors or fitting them with collars, devices and deterrents," said Professor Robbie McDonald, of Exeter's Environment and Sustainability Institute.
"While keeping cats indoors is the only sure-fire way to prevent hunting, some owners are worried about the welfare implications of restricting their cat's outdoor access.
"Our study shows that - using entirely non-invasive, non-restrictive methods - owners can change what the cats themselves want to do.
"By playing with cats and changing their diets, owners can reduce their impact on wildlife without restricting their freedom."
Play in the study involved owners simulating hunting by moving a feather toy on a string and wand so cats could stalk, chase and pounce. Owners also gave cats a toy mouse to play with after each "hunt", mimicking a real kill.
It is not clear what elements of the meaty food led to the reduction in hunting.
"Some cat foods contain protein from plant sources such as soy, and it is possible that despite forming a 'complete diet' these foods leave some cats deficient in one or more micronutrients -prompting them to hunt," said Martina Cecchetti, the PhD student who conducted the experiments.
"However, meat production raises clear climate and environmental issues, so one of our next steps is to find out whether specific micronutrients could be added to cat foods to reduce hunting.
"We also plan to investigate whether different kinds of play have different effects, and whether combining strategies can reduce hunting even further."
The study - based on a 12-week trial of 355 cats in 219 households in south-west England - also examined the effect of existing devices used to limit hunting by cats.
Colourful "Birdsbesafe" collar covers reduced numbers of birds captured and brought home by 42%, but had no effect on hunting of mammals.
Cat bells had no discernible overall effect - although the researchers say the impact on individual cats varied widely, suggesting some cats learn to hunt successfully despite wearing a bell.
Lisa George, from Helston in Cornwall, who looks after Minnie, a three-year-old tabby cat who took part in the trial, said: "Minnie loves to hunt. More often than not, she will bring her prey home and let it go in the house. We've had birds in the bedroom, rats in the waste paper bin (which took us three days to catch), rabbits in the utility room.
"On changing Minnie's food (previously supermarket own-brand), to Lily's Kitchen, I found she hardly hunted at all. This continued the whole time she was on this food. I can honestly say I couldn't believe the difference as regards her hunting behaviour."
George Bradley, from project sponsors SongBird Survival, said: "This latest study we have funded is excellent news for birds.
"The data show that cat owners (like me) can make a few small and easy steps to really improve the health and happiness of our pets as well as make a really big difference for all our wildlife, especially our beloved songbirds.
"Making these easy-to-implement changes will be a win-win for birds, cats and cat owners."
Dr Sarah Ellis, Head of Cat Advocacy at iCatCare, which is part of the advisory group for this research project, said: "We are really encouraged by the findings of this study.
"While many cat owners are wildlife lovers and find the killing and injuring of wild animals by their cats upsetting, many owners also feel that keeping their cats indoors or restricting their outdoor access would impact negatively on their cats' quality of life.
"At iCatCare, we are particularly excited about the positive effects of play - this is an activity that owners can easily introduce at no or little cost, takes little time and is very cat-friendly.
"The mental and physical stimulation of predatory-like play are likely to help keep a cat in tip top condition and provide an appropriate behavioural outlet for its predatory behaviours."
Dr Adam Grogan, Head of Wildlife at the RSPCA, welcomed the results of the study.
"The RSPCA cares for both cats and wild animals and we want to provide advice to cat owners that will benefit both cat and wild animal welfare," he said.
"This project provides us with alternatives for cat owners that are simple and effective and so easy to adopt."
The paper, published in the journal Current Biology, is entitled: "Provision of high meat content food and object play reduce predation of wild animals by domestic cats Felis catus."