Two competing “Duck Boat” tour companies in the City of Brotherly Love are squawking loudly over the right to quack.

Super Ducks (search) and Ride the Ducks (search) – which offer rides in amphibious sightseeing boats – are in a flap over which company has the right to hand out “quacker” noisemakers to passengers to make them sound like the birds for which the boats are named.

“It’s nonsense, utter nonsense,” Capt. Joe Saeger of Super Ducks said of the quacking quarrel.

The dueling companies have been archrivals for a while, battling over the use of a boat ramp and hurling accusations about an employee stealing trade secrets and defecting to the competitor.

And now there's the daffy dispute over which company is allowed to use the duck-bill-shaped, quacking sound-makers on tours.

In 1998, Ride the Ducks actually trademarked its “Wacky Quacker,” insisting the device was its own alone. Super Ducks ruffled feathers by disputing that claim — and a federal judge essentially agreed.

Ride the Ducks is thinking about appealing to get its trademark on the quack back; the company still feels strongly that it should own the exclusive rights to the gimmick.

“That’s what we believe and that’s why we soundmarked that,” said Ride the Ducks General Manager Scott Lewis. “We do stand by that.”

It’s an argument Super Ducks is still shaking its tail at.

Said Saeger: “They quack me up."

Click in the box near the top of the story to watch a report by FOX News' Todd Connor.