At first glance, the ongoing study of Oklahoma’s secretive crawfish frog reads like a nursery rhyme from Mother Goose. A field season triggered by early spring rains. The study’s main character snoring away like the fabled old man. But a research team from Oklahoma State University has spun the opening lines of “It’s raining, it’s pouring…” into a mystery packed with late-night searches, pitfall traps, and even tracking and listening devices.  

Graduate Research Assistants Owen Edwards and Kaleb Banks have spent the past 14 months shedding light on the status and distribution of Oklahoma’s crawfish frog populations with surveys spanning from a single breeding pond to the eastern one-third of the state.  

So far, the duo has captured and tagged at least 83 individual frogs at Atoka Wildlife Management Area and documented 299 breeding populations in 32 counties, confirming decades-old records and logging previously unknown populations along the way. At a time when crawfish frogs are experiencing severe declines across much of their range, the species appears to be thriving in Oklahoma.   

Most Photogenic Frog?  

For Owen Edwards, the crawfish frog is impossible to beat.  

“They’re hands down the prettiest frog in all of North America. They’re just beautiful.”  

Jena Donnell/ODWC

The unique pattern – a myriad of dark blotches offset by lighter, contrasting rings – would be a compelling argument in favor of the crawfish frog winning the “most photogenic frog” award. But few are even aware the species exists.  

The eye-catching appearance and distinctive snoring call would likely draw more attention and fame if only the frogs were aboveground for more than a 6 – 8-week window, and weren’t so fond of cool, rainy nights.  

“They’re a bizarre frog,” Edwards said. “Outside of the breeding season, they live entirely in crawfish burrows.” 

When air temperatures start to climb in February and the first spring rains begin to fall, the frogs leave their prairie burrows and migrate up to three-quarters of a mile to local ponds, intermittent streams, and even flooded roadside ditches. It’s then that Edwards and Banks have the best chance of detecting and capturing the secretive frogs, collecting valuable data, and mapping the species’ known range in Oklahoma.

Getting the Drift at a WMA Study Pond…  

To uncover the mysteries of the crawfish frog on a local scale, Edwards and Banks staked out a handful of former livestock ponds at Atoka Wildlife Management Area where a large breeding population was documented in 2007. On top of nightly visits to the ponds in hopes of capturing crawfish frogs, the research team deployed a series of listening devices in an attempt to estimate the number of frogs in each population and completely enclosed one pond for a more intensive study.  

“We dug a six-inch-deep trench around the study pond’s 900-foot perimeter and installed a drift fence just before the frogs showed up to breed,” Edwards said. “It took a lot of labor and manhours, but it’s a bulletproof way to know how many crawfish frogs are in the pond.”

During the frog’s breeding season, individuals are driven to reach their selected pond and will try to skirt any barrier – including a drift fence – standing in their way. Capture buckets were buried every 33 feet around the inside and outside edge of the drift fence, allowing the team to catch frogs as they attempted to enter and later leave the breeding pond. The arriving frogs were weighed, measured, and tagged with a Passive Integrated Transponder, or PIT tag, that can be scanned to identify individual frogs. Once the frog was processed, it was released into the study pond where it could join the nightly chorus or lay eggs before eventually making its way back to its burrow.  

Last spring, the team captured and processed 43 crawfish frogs at the study pond. In addition to learning more about the frog’s life history, knowing the exact number and makeup of the frogs in the pond allowed the researchers to test how effective the listening devices were at estimating the population size. For this experiment, Kaleb Banks posted five microphones around the pond and recorded frog calls for one hour each night. He later analyzed the recordings in two-minute clips, annotating the millisecond a frog’s call reached each individual microphone.  

“When a frog calls, the sound first arrives at the nearest recorder and last at the furthest recorder. The call may not even be detectable on some recorders,” Banks said. “A software program can then triangulate where in the pond the frog is calling – and tell how many calling frogs there are in a night – by looking at the call’s time of arrival and signal strength at each microphone.” 

Banks is continuing to fine-tune the equipment and model but has been pleased with the realistic results of early tests.   

“The model is prone to underestimate the male population, but this is still a good way to gauge the population size without fencing and monitoring each breeding pond. 

The listening devices and resulting model only give an indication of the breeding crawfish frog population at an individual pond during any given year. Though researchers could use the information to estimate the minimum, maximum, or average number of frogs visiting various study ponds, these numbers wouldn’t apply to every crawfish frog pond across the state.  

“There’s a lot we learn by getting frogs in-hand that we would miss if we were only deploying this technology. This may not fully replace the manual labor but can be used to supplement future surveys and allow teams to cover more ground.”    

Roadside Surveys Offer Look at State’s Crawfish Frog Population 

While the study pond has been a great source of crawfish frog data at the local level, roadside surveys have given insights at how the frogs are faring at the state level.  

“I surveyed 335 roadside sites across 36 counties last year,” Banks said. “And documented crawfish frogs calling at 168 sites in 31 counties.”  

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Banks traveled along public roads in areas with potential crawfish frog habitat to listen for the frog’s telltale snoring calls during the early spring breeding season. In 2023, he documented crawfish frogs calling at 168 sites in 31 counties. 

These surveys not only confirmed the crawfish frog’s persistence in counties with records more than 30 years old, but also recorded frogs calling in two previously undocumented counties, Johnston, and Creek counties. A third county record was verified during the recently concluded 2024 surveys when Banks documented the frogs calling in far eastern Pontotoc County.  

The location data will be used later this year to develop a species distribution model that can help explain the environmental and landscape features that shape where the crawfish frog can be found. But Banks’ survey results have already turned the study’s series of reports into an exciting read for biologists.  

“The baseline for Oklahoma’s crawfish frog distribution comes from surveys by Arthur Bragg in 1950,” Banks said. “More than 70 years later, we’ve confirmed the frogs in every county Bragg recorded. That’s a good sign that they’re doing well in Oklahoma.”  

2024 Season Update 

Dry conditions at Atoka WMA this February and March demonstrated how rain dependent crawfish frogs really are. Instead of being swamped with frogs in the first weeks of February as they were last year, Edwards and Banks had to wait until Feb. 22 for the first crawfish frog, an adult male, to arrive at the study pond. And the second frog, an adult female initially captured and PIT-tagged at the pond in 2023, wasn’t found until Feb. 27. Crawfish frog captures picked up in the following weeks as bands of rain passed over the WMA, and a total of 31 frogs, 13 of which were tagged in 2023, were documented visiting the pond this season.        

Though Banks spent weeks traveling the state in 2023, documenting calling crawfish frogs and sleeping in gas station parking lots, he was excited to again hit the road in 2024 and fill gaps in the map with a special focus on historical sites and areas of the Ouachita Mountains, Ozark Plateau, and Osage County where few or no detections were made. Banks wrapped up the roadside surveys in late March, documenting an additional 131 positive crawfish frog sites, bringing the total to 299 positive sites in 32 counties.  

Much like the nursery rhyme, this project started out with early spring rains and a snoring subject. But Edwards and Banks quickly began unraveling crawfish frog mysteries at local and range wide levels. With this work, biologists have a much better understanding of the population at Atoka Wildlife Management Area and the extent to which the secretive crawfish frog can be found across the eastern one-third of the state.  

This ongoing study of Oklahoma’s crawfish frogs is funded by the Oklahoma Department of Wildlife Conservation and U.S. Fish and Wildlife Service through State Wildlife Grant F22AF02584 with matching resources provided by Oklahoma State University.