Bird tape-covered foam bricks have worked like a charm. I used to put a mask on to clean the bird & bat waste as I didn’t want to aerosolize any potential pathogens (ex #AvianFlu ). A simple physical barrier was the solution. Homeowner had suggested bird spikes, I had explained drawbacks. But they did not include a recent video of a crow removing bird spikes! LOL. https://youtu.be/_Bn9FONAkUA?feature=shared. Pigeons continue to make a mess on side yard. That is manageable (mask + hose).