From 10,000 Birds blog in the USA:
By Corey • July 13, 2012
A large roost of Purple Martins at the Oklahoma City National Memorial and Museum is considered a nuisance because of their droppings so they are being sprayed with fire hoses. Seriously.
You can email the director of the memorial at firstname.lastname@example.org and you should, but don’t expect any remorse or concern, just a form-written response about how gross the bird poop is.