I've capture photos of other birds pooping, although I don't think I've ever gotten a hummingbird, but when I put out a hummingbird feeder suction-cupped to the window above my balcony, I discovered that hummingbirds pee/poop when they feed when I saw the finish on the deck below was being eaten away, apparently by the acidic waste. I did an internet search and found https://wildyards.com/hummingbird-poop/.
