An animal deterrence system projects polarised light in order to deter animals. The light may be plane polarised light and the polarisation may be varied over time. The system is particularly suited to deterrence of birds, but may also find application in deterrence of other animals sensitive to polarisation of light, such as bees and wasps. The system may be used on vineyards or orchards, or around airports, or in any other place where birds are problematic.
