Where did the ducks go?

I live in New York, and I was thinking about the lagoon in Central Park, down near Central Park South. I was wondering if it would be frozen over when I got home, and if it was, where did the ducks go? I was wondering where the ducks went when the lagoon got all icy and frozen over. I wondered if some guy came in a truck and took them away to a zoo or something. Or if they just flew away.