I know a few places with such signs as this where people ignore the signs. There was one such place when I was going to college.
There was a park I used to frequent in downtown Rochester, MI. Paint Creek ran through the middle of the park and it was a great place to go as it was right near downtown. You could see squirrels and ducks and even catch trout.
I’d always seen the signs and never had any desire to disobey them. One spring I found out the hard way why the signs were there. They later, at my suggestion, posted more detailed signs that included some of the reasons not to feed them, not simply a request to stop. I couldn’t convince them to include the photos I took at that time. (unfortunately I can’t find them now)
Among many common reasons many places forbid the feeding of animals is that some animals are prone to carrying diseases or at least allergens. Waterfowl (ducks and geese) especially are notorious for things in there feces that can lead to upper respiratory problems, even in people without specific allergies.
Feeding ducks also tends to attract even more ducks to frequent the area in greater concentrations in search of the free goodies. When grouped in larger numbers it increases their in-fighting with one another as they compete for the new (unnatural/’free’) food source as well as their ability to contract and spread diseases.
Hand feeding wild animals reduces their aversion to humans and their pets in general which can not only lead to humans (and kids) being ‘nipped’ or otherwise assaulted by the already aggressive and competitive free-loaders but can decrease the natural survival instincts of the ducks thereby increasing their vulnerability to ‘real’ predators.
Many of the foods that are provided for free are not as nutritious for the ducks as sources they would seek out naturally. Additionally, the fact they “don’t” have to get it naturally dulls their ability as well as their desire to do so.
More significantly (and the thing I learned that one spring) is that the ducks gain a dependency on the humans for their nutrition. They not only cluster in large numbers, but they come to rely on the handouts for food, get out of shape and often delay flying south.
As winter approaches, when most ducks would be well on their way to warmer climates, these ducks are fattened up on unhealthy food and often weakened from disease. And guess what? The number of people that frequent the parks in the warm, sunny summer days trickles off considerably in the winter months — along with their sources of free munchies!
As these food sources dry up, the ducks still don’t fly south but fight ever more aggressively over the food they have become dependent upon, burning up even more of their (low nutrition) fat reserves.
What I found that spring was the dead bodies along the banks of the park as I was fishing the opening weekend of trout season. Not one or two but literally dozens of them. Bodies of ducks that didn’t fly south, were no longer able to do so in colder weather, didn’t have their hand outs and didn’t survive the winter.
So in short, don’t feed the ducks! When they feed themselves it is better for them — and when you do it, it may eventually kill them!
There’s probably an allegory in there somewhere … do you suppose?

