Fake nests reveal hidden threats to critically endangered bird
Tiny fake nests, modelling clay eggs and environmental DNA are helping CQUniversity researchers uncover the hidden threats facing one of Australia's rarest birds.
Researchers from CQUniversity are investigating nest predation of the critically endangered Capricorn yellow chat, a small bird found only in a handful of coastal marine plains in Central Queensland. With an estimated population of fewer than 250 birds remaining in the wild, understanding what is threatening breeding success has become a critical conservation priority.
Led by Postdoctoral Research Fellow Dr Grace Blackburn, the project uses artificial nests to identify predators that may be targeting yellow chat eggs.
Placed in yellow chat breeding habitat, the nests contain quail eggs and specially prepared modelling clay eggs that retain telltale bite marks from predators. Camera traps and environmental DNA (eDNA) are then used to determine which animals have visited the nests.
Endemic to a small number of coastal marine plain habitats around the Capricorn Coast, the Capricorn yellow chat is listed as Critically Endangered under Commonwealth legislation. The species faces mounting pressures from sea-level rise, habitat degradation, invasive species and climate change.
Dr Blackburn said identifying nest predators had long been recognised as a major knowledge gap in efforts to conserve the species.
"Researchers have been monitoring Capricorn yellow chats for decades, but one of the priority actions identified in recovery planning was to better understand predation," she said.
"Because the species is Critically Endangered and its nests are extremely difficult to locate, we can't risk disturbing real nests. Artificial nests allow us to investigate what predators are present without impacting the birds themselves."
The project has already produced some surprising findings.
While foxes and other mammals were expected to be the main threat, preliminary results suggest native birds may also be responsible for a significant proportion of nest predation events. Preliminary environmental DNA analysis, using samples collected from the modelling clay eggs has identified a diverse range of predators, including some that were not identified on camera traps.
"The variety of predators we've detected has been a real surprise," Dr Blackburn said.
"We initially expected mammalian predators such as foxes to dominate, but birds appear to be playing a much larger role than we anticipated. By utilising multiple methods such as camera traps and eDNA, we are hoping to be able to gain a more robust understanding of the species predating Capricorn yellow chat nests."
The research forms part of broader efforts to protect the Capricorn yellow chat, which faces numerous threats, including habitat loss associated with sea-level rise, invasive plants and damage caused by feral animals such as pigs.
The small bird nests just 30 centimetres above the ground, making eggs and chicks particularly vulnerable to predators.
According to Dr Blackburn, every new piece of information helps conservation managers make better decisions about protecting the species.
"Ultimately, we're trying to fill some of the critical knowledge gaps around predators so that land managers can make informed decisions about conservation actions," she said.
"If we can better understand what's affecting breeding success, we can help improve outcomes for this very special Central Queensland bird."
Originally from Western Australia, Dr Blackburn joined CQUniversity after completing her PhD and was drawn to the opportunity to contribute directly to conservation outcomes.
"This project gives us the opportunity to undertake research that can deliver tangible conservation outcomes for a species that is genuinely struggling," she said.
"It's incredibly rewarding to spend time observing these birds and contributing, even in a small way, to the broader team effort helping secure their future."
The research is funded by Gladstone Ports Corporation and Birds Queensland and is being delivered by CQUniversity's Coastal Marine Ecosystems Research Centre (CMERC), with the research team comprising Dr Grace Blackburn, Wayne Houston, Leif Black and Associate Professor Nicole Flint.
Conservation of the Capricorn yellow chat involves a broad network of stakeholders, including government agencies, community groups, and Traditional Owners, who are working alongside researchers and community partners to improve outcomes for the critically endangered species.
