Kath Shurcliff | Grasswren Project Leader
BirdLife Northern Queensland (BLNQ) has partnered with Southern Gulf Natural Resource Management (Southern Gulf NRM) since 2016 to help them monitor the status of the endangered Carpentarian Grasswren (aka Carpies) in northwest Queensland. The partnership was based on our long-term monitoring of both Carpentarian and Kalkadoon Grasswrens that Graham Harrington initiated back in 2008.
The species is now listed as endangered because it has suffered drastic population decreases in the Northern Territory due to widespread wildfires and persistent, recurring burning regimes. Basically, you can no longer find any Carpies in the Northern Territory!
Then in 2011 and 2012, the unthinkable happened – widespread wildfires destroyed an estimated 50% of good Carpentarian habitat within its core distribution in western Queensland, known as the Buckley River Key Biodiversity Area (KBA; Southern Gulf NRM 2023 report)! That catalysed the endangered listing and a coordinated call for action in Queensland.
Southern Gulf NRM was able to obtain funding from the Australian Government to initiate a regional Fire Management Plan. Each year during the wet season, they work with the managers of several stations northwest of Mount Isa, centred on the Buckley River KBA, to determine where they do controlled burns, aimed at creating a mosaic of different ages of fire scars throughout the landscape.
Our role has been to survey this range of fire scars to see if the birds have preferences in fire scar ages, and if effective refuges remain for the birds; as well as finding new locations where the birds are concentrated. Henry Stoetzel’s PhD research at the University of Queensland is providing us guidance on just where to look for the Grasswrens, and this advice is clearly helping us.
Sourced from birdata.birdlife.org.au
We completed our 2023 surveys in May, but due to the earlier extensive heavy rains and flooding, our access into some areas was restricted. But with these rains, we also expected to find that there had been widespread and successful breeding. And we were not disappointed! A great crew of 14 volunteers provided our most successful year yet.
We found Grasswrens at nearly three-quarters of all the sites we visited - an unbelievable rate! These results continued the trend of increasing numbers of Grasswrens over the past five years. Many of the groups of birds had more than just a pair of male and female, indicating successful breeding, as the young birds stay with their parents. And we even found two active nests - a first for us! We found Grasswrens in several new locations that we had not previously surveyed. These locations filled in gaps between other known locations, and gave further support to Henry’s habitat model - where one can find good Grasswren habitat.
Kalkadoon Grasswrens were also more numerous than previously, and a quarter of all our sites had both Grasswren species. Similar to previous years, numerous Kalkadoons were found along exposed quartzite ridges. On two separate ridges, they were regularly spaced at about 200 m intervals.
We were able to survey three areas with recent fire scars (burns from 2020 or 2023). Our results indicate that both Grasswren species can utilise these recent fire scars of patchy burns, and also find unburnt areas within larger burnt patches.
What have we learned over these past few years since working with Southern Gulf NRM within the Buckley River KBA? Here are some of the highlights.
We now have more than 450 sites for Carpentarian Grasswrens in the Buckley River Key Biodiversity Area, and these are concentrated within six areas.
These six areas include multiple groups within our standard 10-point survey, with each point being 200 m from each other. Henry’s habitat model is a good predictor of where these concentrations are.
Kalkadoon Grasswrens also appear to concentrate in suitable areas, such as along exposed quartzite ridges. They are also found together in over-lapping territories with Carpentarians.
Both Carpentarian and Kalkadoon Grasswren numbers have increased after above-average rainfall during the past few wet seasons. This upward trend continues.
Carpentarian Grasswren breeding can be triggered by rains late into the wet season, as evidenced by active nests in May.
Both species are able to utilise recently burnt areas, especially if within a mosaic that includes unburnt areas close by.
As this phase of our Grasswren surveys finishes, we look forward to the next phase. We plan to continue working closely with Southern Gulf NRM to expand the regional Fire Management Plan to include more properties and link the Buckley River KBA with the Boodjamulla KBA to its northwest. We have just started working with the Indjalandji-Dhidhanu and Lake Eyre Basin indigenous ranger groups, and this exciting partnership will have immense benefits for ongoing monitoring of the Grasswrens and fire management of their critical habitats.
We will need to maintain monitoring of Grasswren responses to fire management, especially to determine if Grasswrens can establish within areas which are currently unsuitable for them because of their fire history.
We will continue to work closely with Henry Stoetzel and his colleagues with their intensive field studies, which should provide important insights to the management actions needed to maintain healthy Grasswren populations throughout western Queensland and into the Northern Territory.
