The most sophisticated types of transparent bird gel feature a three-step system that influences all the birds' senses. First is the sense of sight, the UV light released by the gel looks like a flame to the birds which keeps them away from your location. Then the next sense attacked by these gels is the olfactory one. These gels often have aromatic fragrances such as peppermint oil which acts on the olfactory system of birds and is a natural bird repellent. Then there is the sense of touch, these little disks being in the majority of cases sticky, which makes the birds, especially the pigeons, prone to naturally avoid them.