I happen to know for a fact that snappers do eat baby ducks because I had the odd occassion of actually unknowingly rescuing a baby duck from a HUGE snapper. 10-12 yrs ago a friend and I were bass fishing on Old Hickory Lake on the Cumberland river in middle Tennessee. We heard a big commotion near the bank and saw a mama duck with a bunch of little fluffy ones around her and she was throwing a tremendous fit, in the water thrashing her wings around and quacking a storm. After this went on a few minutes we decided to investigate. The mama duck was circling a baby duck which kept bobbing under the water. He would be floating low in the water one sec then go under for a few secs only to reappear and peep a few times before going under again. I thought he was tangled in fishing line as he was near the bank in shallow water on top of some small limbs lying in the water. We trolled on over and I reached down to see if I could free it from whatever it was tangled in. I reached into the water and up under the baby duck and started to try to lift him with his legs sticking between my fingers but he didn't want to be lifted very easily. I gradually applied more pressure and whatever he was hung in started to give a little and come toward the surface. Expecting to see a stick tangled in monofilament come up out of the water I was surprised to say the least when a snapping turtle head the size of a baseball appeared with the ducks foot in his mouth. As soon as the turtle saw me he let go and disappeared beneath the surface. Apparently the ducks legs were crossed up around a stick and that's what saved it. I tossed it over to it's mamma and she was very relieved to say the least. I felt bad for the turtle though. Probably the best meal he'd had in a year and I snatched it right out of his mouth.