Not to worry. You're probably just hearing the cicadas' loud mating calls.
A county in Georgia, one of the US states currently witnessing a massive influx of the periodical cicadas known as Brood X, has a request: Please don't call 911 about the insects.
Emergency services in Union County, located about two hours north of Atlanta, reports receiving multiple 911 calls for "alarms" in the neighborhood. But as it noted in a Facebook post Saturday, "more than likely these 'alarms' are not alarms at all but a bug, Brood X."
Periodical cicadas are different than annual cicadas. They spend nearly their entire lives a foot or two underground, living on sap from tree roots. Then, in the spring of their 13th or 17th year, depending on the type, mature cicada nymphs emerge for a brief adult stage, synchronously and in huge numbers for a massive (and extremely loud) mating frenzy.
This spring, bugs belonging to one of the biggest broods of 17-year cicadas, called Brood X or the Great Eastern Brood, are crawling out from their subterranean hideouts in 15 states, plus Washington, DC.
That some people may mistake Brood X mating calls for relentless vehicle or car alarms doesn't come as much of a surprise.
The calls of a group of males -- produced via sound-producing structures called tymbals on either side of their abdomen -- can exceed 90 decibels, about the same level as a motorcycle at 25 feet (about 8 meters) away. The females respond to the males' come-hither calls by clicking their wings, and all the back and forth makes for a distinctive symphony.
"It is often difficult to pinpoint where the sound is coming from," Union County officials note. You can hear the cicadas' song below.
Trillions of Brood X cicadas are expected to emerge this year. Some people view the bugs, and their buzzes and chirps, as a wonder of nature. Others, not so much. For those who'd would rather tune the noise out, here are some suggestions.
But humans aren't the only ones experiencing sonic confusion during Brood X season. Cicadas themselves can mistake the loud buzzing sounds of power tools for mating calls, sending them crowding around construction workers or gardeners.