I use airsoft guns. Not really any sound and really fun to use. In our old apartment, we had a tree about 5 feet from our balcony-- and bedroom... stupid birds started getting loud in la madrugada and I just pulled out an airsoft pistol and started shooting. They get the hint after a few times. Just make sure you have one that doesn't look like a real gun-- paint it orange or something. I don't know about SA cops, but when I lived in Denver, the cops shot an old man in bed holding a soda can because they thought it was a gun. Or maybe that was here.