The sounds of recovery

Two sound recordings made thirty years apart in an area devastated by the Black Summer fires tell an unexpected story. Acoustic ecologist Andrew Skeoch explains.

This article appeared in the latest issue of Australian Birdlife magazine. For more great reads, become a BirdLife Australia member and receive our quarterly, award-winning magazine in your mailbox. 

LISTEN to the Waratah Flat dawn chorus:

In the late spring of 1994, my partner Sarah and I followed a narrow forest road in the far East Gippsland high country, arriving eventually at a remote campsite in the Rodger River wilderness—Waratah Flat.  

We could see it had been appropriately named; an uncommonly level area surrounded by ridges and valleys. Majestic alpine ash towered over sassafras, myrtle beech and giant tree ferns, while Gippsland waratahs glowed in the undergrowth. The ecosystem had a ‘Gondwanan’ feel about it: ancient, lush, dense and mysterious.  

It was a magical place, one of those that imprints itself on one’s memory. At the time, we were becoming increasingly interested in nature sound recording. So while Sarah photographed, I directed microphones at anything that caught my ear—the creaking of Gang-gang Cockatoos, delicate trills of Rose Robins and electrifying cries of yellow-bellied gliders as they parachuted between trees in the dark. Dawn choruses were alive with the mewing of White-naped Honeyeaters and the songs of Golden Whistlers, like audible sunshine. What I at first thought to be a European Blackbird turned out to be a native Bassian Thrush, serenading each dawn and dusk. 

At one point during that trip, Sarah and I sat out a violent windstorm. As branches crashed down occasionally, we made the decision to dedicate ourselves to the vocation of publishing nature sound recordings. Maybe the wind was speaking to us. It was certainly a pivotal moment in our lives. The recordings we made there were subsequently published on our first nature album, Tall Forest. 

Preoccupied by subsequent travels, we didn’t return to Waratah Flat. Decades later, in dismay, we followed the progress of the 2019 megafires as they tore through the highlands. Waratah Flat was probably immolated around Christmas Day, and by New Year, the world watched as Mallacoota was dramatically evacuated.  

Over subsequent years, I didn’t have the heart to return to any of those blackened forests that had so inspired us. I could only too easily imagine eerie, silent, apocalyptic landscapes. However, at the end of 2024, I was nearby and had a few days free. Did I really want to go back to Waratah Flat? I wasn’t sure. As I followed those forest roads through a dismal landscape of stark, incinerated trees, I felt more an obligation to document than a desire to visit again.  

Return 

Arriving at the Waratah Flat campsite, I barely recognised the place. In all directions, blackened trees stood like matchsticks against the sky. Some showed regrowth but most were skeletal. Among a tangle of wattle and bracken fern regrowth were the fallen trunks of scores of forest giants, some having been intentionally felled around the campsite to render it safe. It was obvious that what had happened was catastrophic. Five years after the event, I was viewing the aftermath of firestorms calculated to have approached 1,000ºC in places.  

That first evening, I walked down to the Rodger River crossing, surprised to see the old wooden bridge had miraculously survived. It was evidence that the moist, riverine habitat had not risen to those extremes of temperature.  

As dusk settled, a small community of Ewing’s tree frogs began calling. In turning my microphones on them, I suddenly recalled recording the same species in the same place thirty years previously. A Southern Boobook began calling distantly, creating, along with the soft chorus of frogs, a soundscape reminiscent of what I’d heard all those years ago.  

Then a yellow-belly called. It wasn’t close, but it was unmistakable. It was the last thing I would have expected to hear in this charred place. How had it survived? Or had this animal repopulated from elsewhere in more recent years?  

While hearing that grizzly voice lifted my spirits, I was still not anticipating much the next morning. In the pre-dawn darkness, I placed two microphone rigs—one by the river crossing and another off in a scrubby regrowth area—and left them to record unattended.  

The 1994 recording:

The 2024 recording:

The rising birdsong brought another surprise. Instead of being scant, it was rich and diverse. I began excitedly making a bird list from what I was hearing. Over the next few hours, I heard nearly all the species I’d documented in 1994: White-naped Honeyeaters, Eastern Yellow Robins, Brown and Striated Thornbills, Grey Shrike-thrushes, Grey Fantails, Spotted Pardalotes, King Parrots, Eastern Spinebills… The bush cracked with whipbird calls, and I even heard the clear whistles of a ground-dwelling Pilotbird.  

When I assessed the list, the only species I’d heard originally that weren’t audibly apparent were Rose Robins and a Satin Flycatcher. Everything else was present—even a Bassian Thrush, which serenaded from the undergrowth as dusk fell. 

Renewal 

Comparing my bird lists, something unexpected emerged. Not only were nearly all the species I’d documented in 1994 present, but there were many additional ones. I counted half as many species again as I’d encountered originally. These included Shining Bronze-Cuckoos, Dusky Woodswallows, Grey Currawongs, Fairy Martins, an Olive-backed Oriole, two species of cuckoo-shrike, Mistletoebirds, a pair of Brown Goshawks and a Leaden Flycatcher.  

Some of these may have been present in 1994 and I hadn’t picked them up. Others, such as the abundant Flame Robins trilling gently at dawn, were definitely not. Generalising, it seemed many of these ‘newcomers’ were widespread, drier habitat species (Rufous Whistlers, Olive-backed Oriole) or present due to the more open vegetation structure post fire (Fairy Martins, woodswallows). Quite a number of them were migrants.  

It was a similar story with amphibians and mammals. Those Ewing’s tree frogs had survived, as had a population of quietly ratcheting crinias. In addition to the yellow-bellies, I heard the yaps of a sugar glider and the spitting call of a ringtail possum, while microbats of unknown species fluttered in the twilight.  

This increase in species initially surprised me. Subsequently, however, I spoke with a colleague working in the Victorian Alps post fires, who had conducted vegetation surveys based on fire ecology plots dating back decades. Post fire, they’d found an initial increase in plant species, up to 50 per cent in some cases. While they didn’t have similar invertebrate assessments, anecdotally I was told that the regrowth was often covered in bugs and crawly critters, which would go some way to explaining the expanded bird numbers.  

The story that emerged for me was that after fire, even a catastrophic one such as this, natural systems have processes for renewal. The mechanism seems to be that species pile in, each no doubt responding to opportunities in new circumstances. The outcome of this diverse activity is that stability will eventually be reached, and a new ecosystem emerge. 

The scenarios are no doubt complex. A recent collaborative paper has brought together a wealth of research indicating that the frequency of fire has a significant association with biodiversity gain or loss. Natural systems can rally after a single event, but multiple, successive burns lead to losses in diversity, not the gains I encountered.    

Hear the Bassian Thrush in 2024:

Reflection 

It wasn’t just the abundance of species that had me surprised, it was the actual songs. Grey Shrike-thrushes have distinctly localised repertoires. The birds I was hearing were singing the same phrases I’d recorded 30 years previously. Were these shrike-thrushes telling me they were actually from the area, rather than ‘blow ins’ from elsewhere? 

Listening back to my recordings later, I found another species prompting the same question. In 1994, I recorded a pair of male Golden Whistlers duetting with an unusual song, not their commonly heard, spaced, repeated song phrases, but a much more animated ‘whipping’ display.   

The Golden Whistlers in 1994:

And in 2024:

That I’ve documented this behaviour decades apart, during brief visits to the exact same locality when I haven’t heard it elsewhere, I take as significant. I wonder whether birds of both these species were from local populations that had survived the flames, and were possibly even descendants of those I recorded originally?  

Of course, two visits 30 years apart do not constitute a rigorous survey, and I have so many other questions. Had the migrants perhaps not yet arrived when we were there in 1994? Were there species such as the Flame Robins living nearby the whole time, that had now expanded into the regrowth areas?  

Despite my cautious interpretations, I know that listening to the sounds of an environment has much to tell us that the eye may be unaware of. We can both identify which species are present, and what they are doing. We can hear the integrity of their relationships and interactions. We can recognise markers of essential ecosystem health in the coherence of the dawn chorus and other temporal acoustic cycles. And I’ve learned that, with experience, one gains an instinctive knowledge of the condition of life around you.  

On my final morning, I planned a dawn recording before departing, but the howling winds that had begun the night before made this pointless. I felt a sense of unease, as though the place had become unwelcoming. It was time to leave.  

Waratah Flat is healing from a great wound. It may never recover to what Sarah and I experienced previously. Nevertheless, I was glad to have returned to hear a hopeful story I’d not anticipated. But for now, the wind was speaking to me again; the patient is in recovery, visiting hours are over.  

Andrew Skeoch is an educator, author, naturalist, environmental thinker and one of Australia’s best-known nature sound recordists. Find out more about his work at www.listeningearth.com