Finding frogs in the most unexpected places

Jodi Rowley had a simple but difficult mission. To find a tiny mottled green and brown frog that hadn’t been seen in over 40 years, which also lived in some of the most rugged terrain in Australia.

Book cover for wild science

This is an edited text extract from the book Wild Science, a selection of precarious, hilarious and thought-provoking stories from the front line of ecology fieldwork. This compilation is edited by Helen P. Waudby
and published by CSIRO Publishing.

The peppered tree frog is just a little bigger than my thumbnail and known only from a handful of rocky streams on the Northern Tablelands of New South Wales. Since being discovered and named in the 1980s, this tiny frog seemed to have vanished.

Several survey expeditions had searched for the species in the 40 or so years since it had disappeared. However, it was like finding the proverbial needle in a haystack. If the frog was still out there somewhere, it would be one of Australia’s most threatened frog species and in desperate need of our help.

I began my search for the peppered tree frog in the spring of 2016. Like those who had searched for it previously, I started with the most obvious places – the 5 spots where it was originally found. These locations were all streams that flowed from the highest parts of the Tablelands, over 1,000m in elevation, towards the Pacific Ocean. Most of these streams cascaded steeply off the Tablelands, becoming waterfalls as they flowed east. The locals called the area Eastern Falls country.

My colleagues and I searched these 5 streams and dozens of others surrounding them. We hiked alongside them as they flowed across the plateau, then climbed down as far as we could. The streams were challenging to survey as they were very rocky, often with enormous granite boulders, sheer cliffs and scree slopes. The boulders that we clung to weren’t always particularly stable. Overall, it made for some precarious moments.

While we found lots of frogs we didn’t find our target, the peppered tree frog.

From the historical peppered tree frog locations, our surveys expanded out and into some of the most remote parts of the Northern Tablelands. We would stay nearby, not far from the town of Glen Innes, spending 1 to 2 weeks surveying for frogs every night then returning to Sydney, and travelling back up the next month to search again.

The surveys were hard work physically, and typically ended in the early hours of the morning. We repeated our blocks of surveys every month of spring and summer, and into autumn.

We were rewarded with sightings of platypus so close that we almost accidentally stepped on them, with lyrebirds displaying right in front of us and with inquisitive whiskered quolls watching us warily. We saw orchid-covered boulders, enormous carpet pythons and a sky full of bright twinkling stars on still nights.

We also saw frogs aplenty, but not the peppered tree frog.

The following spring, in October 2017, my colleague Tim and I were again up on the Northern Tablelands, conducting our second season of surveys. We set out to survey one of the most remote parts of Guy Fawkes River National Park, a wild beautiful place on the eastern edge of the New England Tablelands.
We were interested in a section of the Sara River named Starlight. This site has been recommended to me by several friends in the Glen Innes community, although each recommendation came with a warning about how challenging it would be to access.

Decades ago, a vehicle trail of sorts had meandered through the forest, which ran from the Tablelands down into the valley where Starlight was located. Few dared to drive down, and reportedly those who did had to tie a huge log to their front bumper bar in preparation for the drive back up. The log was to weigh their car down at the front, hopefully preventing it from tipping up and over backwards on the extraordinarily steep trail, and tumbling back down to Starlight.

A waterfall and a stream in the bush.
Lower Ebor Falls, Guy Fawkes River. Credit: Steven Breese/iStock/Getty Images Plus.

We left the house we were staying in, just outside of Glen Innes, and drove for about 3 hours. The drive started on sealed roads, but not too long into our journey they became dirt roads of ever-decreasing driveability, and eventually became undriveable. We had reached the very edge of the plateau where the streams turned into waterfalls cascading to the coast – Eastern Falls country.

We parked, gathered all our gear into backpacks and began our hike down into the valley. We followed the faint hint of a trail at first, but the bush had largely reclaimed any tracks and we lost any sign of a trail after about 30 minutes.

We slid down the forested slope in our gumboots, winding our way off the plateau and into the valley below, a drop of some 600 metres in elevation. Once in the valley, we walked downstream for several more hours until just before nightfall. We ate our squashed and slightly soggy sandwiches on the edge of the stream we intended to survey.

I’m always most hopeful and excited when I’m at a new site, waiting for dark to fall. In these moments, at any second, I might hear the call of the peppered tree frog!

After dark, we surveyed along the stream for almost 2 hours. We walked together, shining our head-torches on rocks and in the surrounding vegetation, noting all the frog species we saw and heard. We found 10 species of frog, the most common being the eastern stony creek frog. This species was incredibly abundant along most rocky streams in the area. They were so common that we really had to check every rock before stepping onto it. However, despite our hope and best efforts, we didn’t see or hear the elusive peppered tree frog.

When the survey finished, we were still a long way from a bed. Getting down to the stream had been a physical challenge but getting back up to the car was even more so. It felt like we’d never get there, as we hauled ourselves up and up in our heavy gumboots, pausing to gather our breath then beginning the trudge up again. We eventually made it to the car, calves burning. At 3 am we arrived back at our accommodation.

The next morning we were feeling the effects of the hike. I woke up and hobbled into the kitchen to make a strong cup of tea. I knelt down to retrieve the tea bags from a container and, to my surprise, my knees gave out! I was now sitting on the floor. I concluded that we – or certainly my muscles – needed a break from endurance challenges.

Just 100 metres from where I sat on the floor was a small rocky stream, running through the rural property we were staying on. I decided that we would have an easy night and survey that stream, instead of hiking down into a steep valley again.

I felt a pang of guilt, as if I was passing up an opportunity to rediscover the peppered tree frog in favour of a ‘night off’. I was sure we’d only find the most common of frogs, but it would still count as a frog survey.

So, that night, without the need for a 3-hour drive on a dirt track and with no 3km hike down into a valley, we walked less than 100 metres to the stream across flat, freshly grazed pastures. It was our 57th night surveying for the peppered tree frog.

As predicted, we saw and heard the kinds of frogs that you’d expect to find in a paddock near Glen Innes.

Spotted marsh frogs called from flooded grassy areas, and whistling tree frogs and common eastern froglets, both almost impossible to see, were calling along the edges of the stream. All great frogs of course, but nothing out of the usual.

Rounding a bend in the stream, Tim and I simultaneously shone our head torches on a large smooth granite rock in the middle of the stream. A handful of medium-sized frogs sat on the rock. I was almost certain they’d be the very common eastern stony creek frog as they were really the only frog species in the area that sat like that, and they were so very common. However, something about them wasn’t quite right.

We looked closer, craning our heads and tilting our head-torches. These frogs were slightly more rounded in body shape than expected for a stony creek frog, with blunter snouts and a less obvious stripe along the side of the face. And none were the least bit yellow. Tim and I didn’t say anything for a while. We inspected the frogs intensely. Thankfully they didn’t hop away.

‘Are they… Booroolong frogs?’ I finally uttered.

Brown spotty-looking frog.
Australian Booroolong frog (Litoria booroolongensis) resting on rocks. Credit: Ken Griffiths/Shutterstock.

I’d never seen a Booroolong frog in the wild before. They were once common across the Northern Tablelands, as well as the Central and Southern Tablelands. However, around the same time as the peppered tree frog disappeared from the Northern Tablelands, the Booroolong frog did too. The species persisted in a small area near Tamworth on the slopes leading up to the Northern Tablelands and in pockets of streams further south, but it was now endangered and had not been recorded from the Northern Tablelands since the 1970s. It was the last frog species I expected to find. We certainly hadn’t been looking for it.

There was no other possibility. We were looking at the first Booroolong frogs known from the Northern Tablelands for over 40 years. For some reason, this species had managed to survive in this small rocky stream only 100 metres from our accommodation. In the last place we ever expected to find something this important.

For the last year or so, we’d spent well over 100 hours surveying more than 30 different streams scattered across the furthest reaches of the Tablelands. Our focus was on searching the most remote and inaccessible areas, which had necessitated the long hikes, big climbs, very late nights and jelly-like muscles. We never thought that changing our plans and looking a little closer to home would yield such an important result.

For more information about the book Wild Science, visit the CSIRO Publishing website.

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