Cats are very efficient and prolific hunters. Research has shown that domestic cats can have individual preferences for different types of prey and that they will continue to hunt preferred prey even when their numbers are low . In some locations, this behaviour may have significant implications for the conservation of endangered and threatened species.
The only effective way to completely prevent your cat from hunting prey is to keep them safely contained at home. You may choose to do this voluntarily, or you may live in an area where cat containment is mandatory under local government bylaws. Mandatory cat confinement may be night only or for 24 hours/day to your home or within your property boundary. The RSPCA encourages the containment of cats not only to reduce hunting but also to help protect your cat from disease and injury, increase the opportunity for human interaction and reduce disturbance to neighbours. Most cats adapt relatively easily to being confined indoors, especially if this occurs from when they are a kitten. You can read more about keeping your cat safe at home in this article: Is it okay to keep my cat at home all the time?
Offering occasional raw foods in your cat’s diet may also help reduce the urge to hunt, such as a raw chicken neck a couple of times a week. This can also help to keep teeth and gums healthy. Please consult your vet prior to adding these to your cat’s diet to ensure this is suitable.
Finally, should a dead animal be presented to you by your cat, it is best to dispose of the carcass (ensuring first that the animal is indeed dead) as quickly as possible and without displaying any reaction, as a response may inadvertently encourage more hunting. Never punish a cat for hunting. Should the prey animal still be alive, it is advised to swiftly retrieve the animal to check for injuries. If injuries are present or suspected, the animal should be taken to a vet as quickly as possible for assessment. If this is a regular occurrence, then you should seriously consider containing your cat.
If you are not able to confine your cat, you may consider trying a special predation deterrent to help prevent hunting and predation. Research has found that bells on collars are relatively ineffective  but other research has shown that some specially designed cat predation devices may reduce predation [3, 4]. However, there is limited research on this topic and more work needs to be done to determine the efficacy of these devices and their potential effect on cat welfare. Therefore, cat containment is preferred to using any prey deterrent devices.
 Dickman CR & Newsome TM (2015) Individual hunting behaviour and prey specialisation in the house cat Felis catus: Implications for conservation and management. Applied Animal Behaviour Science Vol 173, 76-87
 Calver MC and Thomas SR (2011). Effectiveness of the Liberator(TM) in reducing predation on wildlife by domestic cats. Pacific Conservation Biology, 16, 242-250.
 Calver M, Thomas S, Bradley S & McCutcheon H (2007) Reducing the rate of predation on wildlife by pet cats: The efficacy and practicability of collar-mounted pounce protectors. Biological Conservation Vol 137 (3), 341-348
 Hall CM, Fontaine JB, Bryant KA, Calver MC (2015). Assessing the effectiveness of the Birdsbesafe antipredation collar cover in reducing predation on wildlife by pet cats in Western Australia. Applied Animal Behaviour Science, 173, 40-51.