The roof walker

He has been walking around on the roofs near us for several days. He came to the door one morning to explain that he is doing some sort of maintenance on the roof tiles, and we were not to be alarmed if we heard him walking around on our roof. What is truly alarming is the way he just steps off his ladder (extra) and walks around on the steeply pitched roofs. He doesn't look very agile on terra firma, but on the roof he's an artist. Terrifying to watch.