Here is a link to our dock with the flags:
http://www.math.msu.edu/~drachman/row/no_duck_dock.jpg
This morning the next dock, the MSU varsity dock, was full of ducks. They use barrels and string. The ducks and geese don't even think about getting on our dock. I guarantee if you use flags like this you will never find any duck or goose poop on your dock. I noticed that when ducks get into a dock, they don't fly and land on the dock. They land on the water and jump onto the dock from the water. They probably don't want to get tangled up with the flags. I'm just guessing here. I'm not on speaking terms with the ducks. But as I said, the flags do work.
Ooops. I never even thought about asking permission to put up the flags at our dock. I just did it. People are very happy with the poop-free dock.I'll send the picture to our club trustees and see if they're interested in giving it a try.
Byron