It's so fun when they swim under the water like that! I remember my little Mel, mallard duckling I found under the brooders at the feed store and they told me to take him home... anyway, Mel used to do that when he was about a week old. I let him swim in a bucket... round and round and swooop! under the water for a few laps. He loved it! Didn't want to come out, he would dive every time I reached for him. Not afraid though, he was imprinted on me. Lasted until he was mature and we got him a girlfriend. I could still pick him up any time.