Need some pigeon predators
Your article about suspected pigeon droppings contaminating Fountain Creek conjured up memories of a similar problem that closes Lake Michigan beaches in Wisconsin and Illinois. It is now a foregone conclusion that Lake Michigan beaches close after Midwest rainstorms wash out the sandy beaches, leaching gull droppings into the Great Lake and causing E. Coli levels to skyrocket.
Like Fountain Creek, expensive government studies back then never seemed to precisely pinpoint the culprit of the contamination - until a few communities started finding ways to move the protected species (gulls) off their beaches in the direction of neighboring dunes. Then a pattern arose, as some beaches remained opened while others just miles away were closed. Gull abatement in one community revolved around shooting off a cannon and having trained dogs chase waddling loiterers at intervals that made the flock find quieter, more gentile locales.
The problem is not gulls or pigeons per se; the problem is that there are no natural predators to cull the flocks. In one community in Wisconsin they began to introduce foxes into natural areas near the beaches, which quickly reduced the flocks. I also know of communities that bring in falcons and hawks to reduce pigeon populations. All these remedies are cheaper than government studies and fancy human abatement programs and can keep water with fewer E. Coli problems.