Outdoor cat deterrents
Whether you are trying to keep other cats out, or limit the range of your own cat, there are many deterrents on the market to help.
Your cat may only need, and be quite happy with, the space provided by your garden but cats are natural explorers and will usually go looking for new areas. You cat try to limit this natural curiosity by making any paths, gaps and exits undesirable places to cross. Popular options include laying down citrus peel or spray, using spiky plants or even rolls of plastic spiking (Designed to be painful but not harmful) Cats are said to dislike moving reflective surfaces (such as CD's reflecting light) and some bird scarers may also work. There are also a few plants which produce odours which cats do not like, the most well known of these is Coleus canina
, often sold under the name of 'Scaredy-cat' which can also be used as a deterrent.
longer term deterrents
Whilst the above methods may work, citrus peel or sprays need replenishing, prepared treatments are expensive over time, and spikes or scary objects can be overcome by a daring cat. More permanent solutions include water jets, ultrasonic scarers, and electric collars.
If there is a particular spot where your cat could easily get in or out of your garden, you can purchase a device called a 'scarecrow' - this attaches to your mains water and delivers a jet of water when activated by a motion sensor. When your cat walks in the area it gets an unpleasant jet of water, runs away, and learns to avoid the area. The only downsides of this method is that the area should not be a path where humans are likely to go, or they will also get wet, and the device and supply hose must be kept free from freezing conditions.
A determined cat will find a way to reach its destination
There are a number of collars on the market which can be set to deliver a mild electric shock to your cat if it strays too close to a set boundary. The boundary area is normally set by a wire or series of transmitters which produce a localised signal. If the device on your cats (or other pets) collar gets within range of the signal, a warning sound or buzz is produced. If the cat does not move away, the warning is followed by a mild shock. Your cat will soon learn the boundary area and avoid going outside it. There is much debate over whether these system are humane or not, with strong arguments on both sides.
Although sometimes expensive, ultrasonic deterrents receive good reviews and appear to work well. These small devices emit an ultrasonic sound which is inaudible by humans but can be heard by cats and is disliked. When cats approach the device they quite quickly stop and back away. Other animals and wildlife can also be affected. Lower quality units may not be as powerful or long-lived so try to read some reviews before purchasing, and you may need more than one to cover several areas.