He especially loved birdseed which, I was told was very bad for ducks. But, he spit out the seeds he didn't like. It was kinda funny seeing him take a big beak full of seed and see him spitting most of it out. I tried to find out what, exactly, he was filtering out and favoring so I could just get what he liked, but couldn't figure it out. He hated eating things like cracked corn, but would eat bread sometimes. At the end, he mostly ate grasses and snails.