Persistent or Stupid

My parents live on a pond where lots of ducks and turtles live. The kids love to feed the ducks and turtles and this year the ducks and turtles seem a little more aggressive than in previous years. Apparently lots of people have been feeding them. My parents don't feed them normally so whenever we come and the ducks see us walk outside they seem to flock to my parents part of the pond. This afternoon after we fed them we decided to take a walk around the pond. As we walked we had about 30 ducks follow us around the pond which was a pretty funny sight to see. Apparently they weren't quite ready to give up on the hope that maybe we were hiding another loaf of bread somewhere.

Then tonight while we were sitting outside the ducks came right up to my parents fence begging for food. The fence has wire on it so the ducks can't get through it so instead they went into the neighbor's yard and snuck into my parents yard that way. We had to chase them out a couple of times. Are they persistent or just stupid birds? My dad would stay stupid but the verdict is still out.