NEW ORLEANS (AP) - Invasive treefrogs have established themselves in New Orleans, probably arriving on palm trees from Florida that were planted in the Audubon Zoo.

The U.S. Geological Survey says the zoo and a neighboring park have the first established population of Cuban treefrogs on the U.S. mainland outside Florida, where they've been multiplying at least since the 1950s. A study in the journal Biological Invasions says the fist-sized creatures eat smaller frogs and are a likely threat to those in a national park across the Mississippi River.

Dusty Pate is natural resource program manager at Jean Lafitte National Historical Park and Preserve. He says USGS has been checking the park's Barataria Preserve for Cuban tree frog calls since 2014. He says they're the latest among many invasive species threatening the park.