But recently the anti-pigeon shoot forces landed a new powerful ally in the Delaware River Keeper Network - environmental protector of the waterway that courses the length of eastern Pennsylvania.
Their complaint alleges that the pigeon shoots, which occur many times a year, pollute the Delaware with lead shot and fragments, as well as dead and injured birds.
The shoots attract animal-rights' protesters, including one who positioned a boat near the club during a shoot and recorded video of what appears to be shot and fragments falling into the water around him.
The gun club did not respond to a request for comment.
According to the suit, the club is about 132 years old and hosts at least a dozen trap-shoot meets a year. Instead of using clay targets, the club uses pigeons.
The pigeons are stuffed into steel traps and then launched into the air to be shot at, the suit says. Hundreds of dead and injured birds land on club property, the shoreline, or in the river.
In 2010, the club submitted applications to the U.S. Coast Guard to request a "safety exclusion area offshore" for safety reasons, according to the suit.
At some point, the club withdrew its applications, but has continued to host the pigeon shoots, the complaint alleges.
A Coast Guard spokesman could not be reached for comment.
Van Rossum, whose title is Delaware Riverkeeper, said the suit was necessary because "none of these regulatory agencies or the police are stepping up to do something about this."
Her group sent a notice to the club in October 2010 threatening a lawsuit if the shoots didn't end. The notice satisfied a 60-day-notice requirement for filing a suit based on the Clean Water Act, Van Rossum said.
"Shooting over the river is also a safety hazard and a disturbance for those who are trying to enjoy this reach of the river for wild birding, boating, fishing, or otherwise," she said.
The complaint asks the court to halt the pigeon shoots until the club complies with federal environmental laws. It also asks for the club to remediate any damage to the environment and be subject to civil penalties.