I once rescued a duckling as well. sometimes duck mothers simply decide they’re just gonna ditch a kid. took about 3 months until it was ready to be released, I had built it a full outside enclosure where it could stay in the meantime, so it was mostly self sufficient towards the end. it definitely did learn to recognize me, and while it still hated being touched, it had absolutely bonded and kept trying to run back to me when I released it.

luckily where I grew up there was a spring fed one where ducks stay year round, so I can actually confirm it’s still there and recognized me up till about 3 years later.

they’re absolutely vicious tho. still have the scars from when I had to handle it!