An electronic bird call system is a special playback device designed to attract colony-nesting birds such as house martins, swifts, and alpine swifts. These devices are placed near artificial nests to support the natural process of nest colonization. Colony-nesting birds are social animals that are guided by the calls of their conspecifics. In the initial phase, when no birds are present at the nesting sites, it can take several years for the first residents to settle, even in favorable locations. This is where electronic bird call systems come into play. They play bird calls in high-quality sound, helping to quickly attract the first arrivals to the new nesting sites and help them feel at home there. The correct use of these devices can make a significant difference and significantly shorten the colonization period.