GunaiKurnai Elder Uncle Russell Mullett (right) and Bruno David (standing in the pit of the 1971-1972 excavations), Cloggs Cave 2022.

Photo by Jess Shapiro, courtesy of the GunaiKurnai Land and Waters Aboriginal Corporation.

By Matthew McDowell, Bruno David, Russell Mullett, Joanna Freslov, Rap Manager, Jean-Jacques Delannoy, Jerome Mialanes, Cathy Thomas, Jeremy Ash, Joe Crouch, Fiona Petchey, Jessie Buettel, and Lee Arnold.

This Plain Language Summary is published ahead of the article discussed; check back soon for a link to the full paper.

Over the past 26,000 years, Cloggs Cave, a small limestone cave in East Gippsland, southeastern Australia, has been home to some 2,600 generations of Masked Owls. These predatory birds like to roost in caves during the day and hunt small mammals such as rodents and marsupial mice at night. Every night before they head out to hunt, the owls regurgitate a mucous-covered pellet of fur, bone and other indigestible bits of their previous night’s meal. Each pellet adds to the cave’s bone accumulation, but the species of animals the pellets contain change with the environmental conditions of the owl’s hunting range, building up a record of climate and environmental change around the cave over time.

To try to understand how the owls’ prey changed over the tens of thousands of years of accumulated deposits, we dug a small, 1.53 m-deep hole in Cloggs Cave’s dirt floor. We collected and identified the bones that had accumulated over the generations of owls. To our great surprise, we found that the mix of prey species changed very little over the past 26,000 years. Thanks to 69 radiocarbon dates that finely date the excavated sequence, we knew that the bones from those layers had not been mixed up or reworked. But the radiocarbon dates also told us that some of the bones were left in the cave during the Last Ice Age when it was cold and dry, whereas others were left there much more recently under warmer and wetter conditions.

We also noticed that the prey species found in the owl pellets had come from a range of habitat types that persisted through almost the entire period represented by the excavated deposit. The best explanation for the continued presence of small fauna from distinctive habitats spanning many thousands of years, and a lack of species change over time, is that the land surrounding the cave had been managed by the Old Ancestors who used fire to maintain a patchwork of distinctive plant communities. Such practices are well known ethnographically and from Aboriginal knowledge-holders today. ‘Cool fire’ cultural burns of this kind only burn the undergrowth and some of the ‘ladder fuels’ that would otherwise permit wildfires to reach the crowns of trees. As cultural burns are small in extent, they create a patchwork of habitats across the landscape, each habitat also resulting in its own range of animal species.

The Cloggs Cave small fauna bone assemblage is of particular interest because it signals that animals from almost every habitat in a patchwork of habitats existed near the cave nearly all of the time over the past 26,000 years. The owls hunted across every plant community, building up a long record of animal bones from a mix of each habitat. This also suggests that traditional land management practices may be the best way to look after the plant and animal biodiversity of East Gippsland.