Staying around, showing up as much as you can is the only thing they don't like. I have tried pottage, wooden and even marble eggs as a deterrent which all got stolen. Very clever and determined birds, crows, maybe the odd one got a sore beak. Never leave ducklings without protection from attacks. marka, I would like to know if you actually saw that it was crows attacking your ducks. I've never come across that in all the years I've watched, they co-exist well besides stealing eggs and feed.