Help with my little mallard...?

I found a mallard egg and incubated him until he hatched. Suprisingly he's survived for three years with just me taking care of him. He doesn't even fly south in the winter. The problem is he follows me everywhere. I ride a bicycle mostly so it's easy for him to keep up with me but its hard to explain to people all the time of why he's with me. I've tried to set him free but he always comes home. I love the little guy but I want him to be happy in the wild instead of grounded most of the time with me. ps. his name is Duckerdoodles.