SPCA acknowledges that people may sometimes wish to prevent or deter wild animals, or roaming companion or farmed animals, from accessing areas. For example, gardeners may wish to keep roaming cats out of garden beds.

Where the issue is related to nuisance caused by roaming companion or farmed animals, talking to the owner is a recommended first step. There are steps people responsible for the animals can take such as securing stock fencing and keeping their cats safe and happy on their property.

Physical exclusion methods, such as fencing, are currently the only evidence-based approaches to prevent animals from accessing areas. Fencing should rely on physically blocking access rather than the use of aversive stimuli such as electric shocks.

Before using deterrents, attractants such as food should be removed and access to shelter should be restricted, where possible. For example, roaming cats may be attracted by food left outside sandboxes or freshly turned soil, rubbish bins not properly secured, rodent populations, and the presence of other cats that are not desexed. Landscaping changes can be used to create an environment less inviting to unwanted animals, for example replacing dense shrubbery can make gardens less appealing to rats or covering swimming pools can make gardens less appealing to waterfowl. Bird netting can be used to prevent birds from roosting, perching, or nesting in places where accumulation of their faeces is a problem. Removing or restricting access to attractants will make it easier deter animals from entering the area.

SPCA is concerned about the use of deterrent or exclusion devices or methods where the welfare impacts are poorly understood.

There are many deterrent devices on the market but some of these lack scientific evidence to prove efficacy, ensure these devices do not have unintended welfare impacts on target animals or impact the behaviour or welfare of non-target animals.

For example, one study examining the use of ultrasonic deterrents on cats found minimal impacts on behaviour and cats actually spent more time in the reported ultrasonic range of the device.

SPCA opposes the use of deterrents that cause severe welfare harms.

Some products intended to deter animals may cause unintended welfare harms. There are several types of bird deterrent gels available to use in New Zealand that claim to act as a deterrent by causing a bird temporary discomfort due to their feet contacting the gel that has been applied in areas where they nest and roost. While these products are marketed as deterrents, there have been multiple incidents where birds have become coated in the sticky gel, leading to suffering and death.

SPCA advocates for more investment into research on the impact of deterrent methods and devices.

There are many deterrent methods and devices where the welfare impacts on animals is poorly understood. For example, those used to protect fish farms from seals and seabirds. SPCA advocates for round-the-clock staffing to ensure monitoring and response to incidents that involve wild animals are managed as quickly as possible.