Meet the chirping frogs of Austin. They are everywhere, but you never see them.

It’s the curse of radio reporters. If you hear something mysterious, unexpected or new, you want to get that sound. It doesn’t matter what time of day. It doesn’t matter what else you’re doing. You want to capture it. What if you never hear it again? What if it is Important? You have to get it.

I have had this compulsion with a specific sound around me for years. I hear it mostly, but not exclusively, in the spring and early summer. And it is not, strictly speaking, one sound.

It is instead a collection of sounds that seem to come from the same source. It’s a kind of high-pitched screeching, peeping, whistling, chirping. It comes from trees, rocks, walls and yards. Sometimes it even seems to come from the ground. And it always seems to be the same animal making the noise.

It confused me because it sounded like it could be a lot of different things, and reviewing the dozens of recordings I’ve made didn’t narrow it down.

I thought they were baby birds tweeting in their nest. It can sound almost exactly like that, except that there is a gushing and creaking component that ruins the impression.

The screeching sound reminds me of crickets or katydids and for a moment I thought it must be a bug.

But the sounds seem scattered and irregular. They do not follow the rhythm of insects. Sometimes they also almost sound like a whistle, which I’ve never heard a cricket do.

I even briefly entertained the idea that geckos were the cause. I’ve heard that geckos can make noises, and the noises started around spring when I started noticing them in my yard.

But some theories pointed to a less organic origin. One of my neighbors even thought the whistling was coming from a leaky or pressurized water pipe.

I have seen many things in my yard: bugs, birds, snakes, lizards, toads, raccoons and hookahs.

I have never seen a frog.

Turns out they were frogs.

People hear frogs all the time but never see them

There’s a place on the UT Austin campus that Tom Devitt calls “the frog room.” Aptly named, it features shelves of terrariums, each home to a different species of frog.

Devitt is a professor and researcher at UT Austin who specializes in amphibians. After emailing several experts about our neighborhood mystery, I was connected with him and invited to the frog room to reveal the likely source.

“A lot of people have never seen one, but you hear them all the time,” he said as he dismantled a terrarium that appeared to be largely filled with a piece of limestone.

From inside the stone, Devitt pulled out a small frog. It was no more than an inch and a half long, brown in color with brown spots. It looked very shy.

“This species is called a reef frog,” he said. “They are the original species.

Devitt calls them mysterious. Small, hides well, hard to find.

He said that’s the challenge of researching them: It’s really difficult to observe them in the wild. There are also different types of chirping frogs around Austin.

Cliff chirping frogs prefer rocky outcrops on the west side of town: hence limestone. But Devitt suspects what I heard in my yard might be Rio Grande chattering frogs.

This is a closely related species that tends to settle in trees and vegetation. They are also more recent arrivals to Austin, perhaps coming from South Texas on potted plants.

“There used to be a big nursery in Brownsville, which is kind of where they’re from,” he said. “We think they probably came from here, although we can’t be sure.”

Rio Grande Chirping Frogs have spread across much of Texas and Louisiana. So far they seem to occupy a slightly different ecological niche than Cliff Frogs and offer little competition.

Frogs are everywhere, but we don’t know much about them

Chirping frogs aren’t like most frogs you’ve heard of.

For one thing, they don’t need much water. There is no tadpole stage for these frogs. They just lay eggs and the young hatch directly from them as little frogs. So they can live in backyards, like me, without a regular source of irrigation.

Because they lay eggs, they also behave differently. Whereas most frogs simply fertilize their eggs in water and leave them to their own devices. Chirping frogs stick around and take care of them.

In fact, male frogs may actually be the primary caregivers.

“They’ll be sitting on eggs.” Move them,” Devitt said. “I think it’s usually just protecting them from predators.

They somehow survive the Texas drought and heat waves – probably by slowing down their metabolism. But how exactly this works and how they know when to do it is not entirely clear.

In fact, the more we talked, the more it became apparent that we didn’t know much about these frogs. Although they are everywhere.

“I just think it’s fascinating that we have biodiversity around us that we know next to nothing about,” Devitt said.

But he wants to know.

How exactly do they reproduce without water? How far will they go in their lifetime? How long do they live?

“We have no idea,” he said.

Actually, it’s not even entirely clear why they make those strange noises.

“They make two types of calls,” Devitt said. “One of them is a kind of little trilling. The other is a kind of insect whistle or chirp.’

One sound is probably used to attract mates. The other to guard the territory. But again, Devitt needs to study them to find out.

“I want to know everything about these frogs and what it’s like to be,” he says. “That’s what I’m after.”

To do this, you need to find them.

So it was a few weeks later. KUT photographer Michael Minasi and I joined Devitt at Brackenridge Field Laboratory on Lake Austin Boulevard for a frog hunt.

Come frog hunting

The trail Devitt chose is perfect for reef frog hunting. It runs alongside a former quarry where blasting has exposed a limestone rock face that provides the perfect setting.

As I walked the trail at night, my microphone picked up bugs, birds, and wild animals rustling through the undergrowth. But one thing we didn’t hear much about was the chirping of frogs.

“As it got later in the season, they came out less and less,” he warned.

Fortunately, he didn’t need to hear them to catch them.

One by one, Devitt spotted the frogs like shiny pennies on a rock in the beams of our flashlights.

We found four that night despite their reluctance to chirp. Some were very small, maybe half an inch long.

“It makes me wonder if they are the ones that hatched this year,” he said.

He left the little ones alone. But he picked up one male to bring to the lab.

He hoped to see if the frogs mated in captivity to learn more about how they reproduce and raise their young.

But when I called a few weeks later to check in, he said he had no luck and returned them to the wild.

He thinks he may have waited too long into the year and collected frogs that were no longer interested in mating.

One reason for this theory? The super tiny frogs we found. If they were newly hatched, did they signal the end of the frogs’ mating season?

“I don’t want to speculate too much,” he said. “But… it’s not that often you see small ones and we saw them pretty quickly.

So in lieu of answers, we end this story with one more question about the mysterious chirping frogs of Central Texas.

Did we help welcome into the world this year’s new generation of reef rattlesnakes, freshly hatched from some hidden clutch of eggs?

There’s no way to know yet. But Devitt plans to look for answers next year, when the air once again fills with strange whistles, whistles and chirps.