Decathlon sells cheap and very lifelike dummies of ducks in the hunters section. I liked them so much that I decided to turn it into a robot.
I took parts from an old quadcopter. Only had to buy an underwater motor.
The duck knows how to quack. To do this, it has an mp3 module with an arduino installed that receives a signal from the FS-i6 remote control.
Live ducks are afraid of it only at a distance of 50 centimeters, further away it is indistinguishable from living ones.