Feral pigeons pose health risks as well as damaging buildings. Pigeon excrement often contains dangerous pathogenic germs like salmonella. On buildings or at locations where the excrement is allowed to buildup the area is contaminated by the obstrusive smell of guano that annoys - especially in the summer months.
The aggressive toxic excrement accelerates the decay of facades and ornaments. Specifically the historic buildings and monuments are affected. The cleaning of contaminated buildings requires permanent high sums.
The pigeon pest increases. The removing of the clutches, resettlement in pigeon lofts, prohibitions of feeding, pops, ultrasonic, assignment of raptors, etc. remain largely unsuccessful. Ovulate inhibitors were prohibited. Poisoning acts are not disposed and are prohibited. In this situation only the pigeon repellent exists. For this purpose the pico-system was developed in accordance to animal welfare.