Swarms of field crickets are out day and night in Green Country, and the bugs might be around for two to four weeks.
But this phenomenon has actually drawn scientists' attention for at least 60 years.
The chirping has been nearly constant on the University of Tulsa campus this week. Thousands of inch-long, black or dark brown crickets are gathered here and at several other spots in Tulsa, Broken Arrow and Owasso.
They cluster together in plain sight, hundreds of them giving walls and floors a living, chirping texture. It's all a bit unsettling.
"I was amazed," said Ed Hirshburg, who was on campus to buy football tickets. He saw a swarm covering patches of concrete bleachers near some tennis courts. "I'd never seen that many in one place."
"[It's] like from the Bible, a legitimate plague!" said student Jeremiah Neely, who was on his way to class with fellow student Cara Douthitt.
"That's definitely the word I would use, actually, is 'plague,'" she said.
The swarms have also caught the attention of entomologist and University of Tulsa professor Peggy Hill.
"To see them in those numbers that close together is really odd," Hill said. "I don't recall hearing this happen before with crickets."
Last summer Tulsa had a similar surge in the field cricket population. Some think the abnormally hot, dry weather fueled it.
The same thing happened 60 years ago. A 1953 report from two Oklahoma State University researchers talks about severe drought preceding swarms of crickets so huge that some streets were too dangerous to drive on because of all the crushed bugs.
That weather pattern wasn't around this year. Yet the crickets still came.
"Happening again this year definitely surprises me, because I thought, 'Oh, wow. They've just emerged all at once. It's a huge spike because of the rains that came after the long drought,'" Hill said.
When a certain phenomenon happens, scientists are interested. But when it happens again under very different circumstances, now you've got their attention.
"If you see an anomaly more than once, then it ceases to be an anomaly, and you need to look at why," Hill said.
Hill's recent work has focused on the little-studied Prairie Mole Cricket. It's sort of like the legendary griffin, except, instead of a lion with the front half of an eagle, it's a two-inch cricket with the front half of a mole.
She can only speculate on why the field crickets are out in force again, but she knows the swarming behavior is out of the ordinary.
"It is weird, and it's not normal, and it probably isn't going to promote the survival of individuals or of their ability to mate," Hill said.
For one thing, these orchestras — yes, a group of crickets is called an orchestra — sound like one big noise to us. Most of their chirping is meant to attract and locate that special other cricket.
But layer all those calling songs together, and even the crickets get confused.
"The chances of attracting, you know, a female by one individual are going to decrease if there's hundreds of them together," Hill said.
Then there's that other issue with crickets jumping everywhere.
"To be honest, I'm trying not to step on them," said Timothy Bell, a grounds keeper at the University of Tulsa. "I feel like I'm going to harm the ecosystem or something."
Not everyone was as mindful of the insects.
"There's the remains of some on my shoe right now, actually," Neely said.
Some people are grossed out, and entomologists' curiosities are piqued. But there are also a few people who will actually enjoy having all these crickets around for the next few weeks.
"You can call it peaceful, the sound that they make," Bell said.
Speaking of the sound they make, Hill took a few minutes to listen to it after she was interviewed. She says the increased amplitude and frequency of certain chirps, along with the crickets' odd behavior, may indicate they're a different species.
But that would take much closer study to determine.