Shorebirds serve as important indicators of coastal and wetland ecosystems, and their widespread distribution highlights their ecological significance. Although wading shorebirds are infrequently found in the fossil record, a remarkable collection of shorebird fossils has emerged from Pleistocene deposits at the Naracoorte Caves World Heritage Site in South Australia. Recent studies on these fossils provide insights into the evolution of wetland environments, revealing that flourishing habitats vanished with climate shifts as far back as 60,000 years ago. The research links a drying phase around 17,000 years ago to the decline of many of the nine or more shorebird species discovered in one of the Naracoorte Caves.
Red knot (Calidris canutus), near Grinet, Brittany, France. Image credit: Stephan Sprinz / CC BY 4.0.
“Shorebirds are rare in the fossil record, making the discovery of numerous shorebird fossils in Blanche Cave surprising,” stated PhD candidate Karl Lenser from Flinders University.
“This finding suggests that wetlands and tidal flats—vital feeding grounds for plovers, sandpipers, and other shorebirds—were more prevalent during the last Ice Age.”
Currently, climate change and habitat loss are contributing to the decline of Australia’s shorebird populations.
Gaining insights into how these species adapted to historical climate changes may be essential for forecasting their future.
Lenser and his team were particularly intrigued by the remains of the Plains Wanderer, an endangered bird found mostly in Victoria and New South Wales, which was among the most common fossils identified in this study.
Out of approximately 300 examined bones, more than half were identified as those of Plains Wanderers.
“Today’s Plains Wanderers are selective about their habitats; however, other fossils from Naracoorte indicate that the area once featured wooded environments—starkly different from the treeless grassland they inhabit today,” Lenser explained.
Naracoorte represents the only fossil site in Australia with such a substantial population of Plains Wanderers, indicating a significant decline in their numbers over the last 14,000 years due to habitat restriction.
Dr. Trevor Worthy from Flinders University highlighted the uniqueness of this sandpiper fossil sample, noting its representation of migratory species that travel from the Northern Hemisphere to spend winters in Australia.
“This includes three species from the Calidris genus and the Latham Sandpiper (Galinago hardwickii),” he added.
“Fossil assemblages also include blue-bellied plovers that migrate from Australia to New Zealand for breeding.”
“Fossil evidence shows that two young birds flew approximately 2,000 km from New Zealand and were captured by owls near Blanche Cave in Naracoorte,” Dr. Worthy explained.
“There remains much to uncover about Australia’s bird species from the last Ice Age, and fossils from sites like Naracoorte are crucial for filling in these knowledge gaps,” Lenser noted.
“Naracoorte Caves holds a 500,000-year record of biodiversity in Southeast South Australia,” stated Dr. Liz Reid from the University of Adelaide.
“As this study clearly demonstrates, caves offer a glimpse into pre-European landscapes, providing valuable information for the conservation of endangered species today.”
Visitors to Naracoorte Caves can explore the excavation site and delve into the science behind South Australia’s only World Heritage Site.
Findings have been published in the online journal Old Trogia Electronica about the study.
_____
Karl M. Lenser et al. 2026. Fossil shorebirds (order: Charadriidae) revealing a Pleistocene wetland trend at Naracoorte Caves, South Australia. Old Trogia Electronica 29 (1): a2; doi: 10.26879/1608
Source: www.sci.news
