Am I right that the only effect of food is to direct the ducks? They seem frustratingly uninterested in food. I had to go look at the source code to make sure that food was even supposed to do anything at all, which isn't ideal.
I did have a bit of fun doing a bunch of clicking and watching the ducks reproduce. Although I wasn't really sure what was going on there for a bit. I thought that maybe I had fed a duck enough that it got an "extra life" powerup or something. Eventually I figured it out.
I could see this getting interesting if you expanded the types of things with different effects you could drop on the map. Maybe give the player a random thing to drop.
Even though I found the gameplay a little unsatisfying, I am tempted to get back in there for a better score, so the leaderboard seems like a great use of time.