Folks there don’t like to talk about it — the clamor they hear at night in their well-groomed homes on Thunderbird and Britannia lakes — because they’re afraid. “Some people don’t hear it, but I think many are too embarrassed to talk about it,” said Barb Peet, who lives on Britannia Lake and was more than happy to talk about the mystery. “It sounds like a symphony.” But, residents reckon, if they talk about the eerie sounds to outsiders or even among themselves, then people might think they’re off their trolley. So folks quietly go about wondering if the nocturnal din, a beating sound some described as a series of low-pitched bellows, could be coming from the lake — actually two lakes that were built in the form of shamrocks (hence the Eight Lakes moniker) and are just a short boat ride to the Caloosahatchee River through a few canals — or from a creaky sewage pump station nearby or from something supernatural. When Bill Thompson, who also lives on Britannia Lake, first heard the noise, he thought it was bull frogs in his attic. “We checked but didn’t hear anything,” he said. “But you could hear it in the house. My neighbor told me it was the result of incoming and outgoing tides. I thought bull frogs would be a better answer.” A few neighbors whispered that the culprits could be fish or maybe alligators who are mating this time of year. But gators don’t like saltwater much and how could a fish make that much noise? So the residents just aren’t sure.