PLAINFIELD, Ill. -- Visitors to a south suburban lake on Saturday found their much-sought-after peace interrupted by an unexpected visitor, an alligator lurking among the herons in the Will County rookery.

The Joliet Herald News reported Tuesday that a 4-foot American alligator was spotted by bird watchers, then seen again Monday morning by Will County Forest Preserve staff.

On Monday, Forest preserve volunteer Rita Renwick first saw the alligator resting on a log near a group of black crowned night herons.

"I thought, 'Am I seeing things? What could that be besides an alligator?'" said Renwick, who has led interpretive nature walks at the rookery for 18 years. "I've never seen anything like this."

Renwick e-mailed forest preserve spokesman Bruce Hodgdon about the alligator. Hodgdon set up a meeting with forest preserve staff and members of the Chicago Herpetological Society at the lake Monday afternoon.

The plan, Hodgdon said, is to catch the alligator alive, rehabilitate it and release it into its native habitat.

But the alligator was elusive Monday, surfacing when the forest preserve staff first arrived, then remaining submerged, the paper reported.

"It's a waiting game now," said Dan, a Chicago Herpetological Society member who declined to give his last name.

"All you're going to see sticking out right now is going to be nostrils and a pair of eyes," he said.

The alligator was probably placed in the lake by someone who kept it as a pet, officials said.

Fully grown American alligators are usually 12 to 16 feet long, Dan said. The alligator in Lake Renwick is young, but has likely outgrown its cuteness, it was reported.

"They go from something fun to watch eat to something that thinks you're good to eat," Dan said.

It has been in Lake Renwick no more than a couple of weeks, Dan said, judging by how clean it was. It would eat anything it could catch --including birds, he said.

So far, the rookery residents appear to be defending themselves just fine. They were observed ganging up on the alligator to drive it back into the water when it crawled on their island.

Traps baited with chicken legs were set for the creature Monday afternoon. Because the nature preserve is closed to the public most of the time, the alligator likely isn't a threat to residents.

"This is paradise" for the alligator, Dan said, adding that the reptile likely will not leave the lake on its own.

Special thanks to Janet Lundquist, of the Joliet Herald News, for information in this story.