The Carpentarian Grasswren, Amytornis dorotheae, has a restricted range in rocky spinifex country along the border of northwestern Queensland and the Northern Territory. The Kalkadoon Grasswren, Amytornis ballarae, is found in similar habitat but only in northwestern Queensland around Mount Isa. Both species rely on spinifex for food and shelter. Grass fires are common in this area and the condition of the spinifex depends on its age since burning. Several Important Bird Areas (IBAs) have been established in this region to protect the grasswrens.
BANQ carried out surveys, organised by Graham Harrington, in these IBAs in 2008 and 2009. The objective of these surveys was to find out how the density of Grasswrens is affected by the age of the Spinifex.
These surveys were undertaken as part of the Important Bird Areas Project. The Carpentarian Grasswren is the target species for three IBAs - Wollogorang in the NT, Boodjamulla (Lawn Hill) national park and Buckley River to the north of Mount Isa.
Another survey on Carpentarian Grasswrens was carried out by BANQ under contract to the Queensland Department of Environment and Resource Management (DERM) at Boodjamulla (Lawn Hill) National Park in 2011.
The Kalkadoon Grasswren was found to be relatively common within its restricted range.
The Carpentarian Grasswren was found to be still widespread in Buckley River IBA but only in small numbers in Boodjamulla IBA. In the Northern Territory, its known distribution was enlarged but it is present only in very small numbers. The area near Borrolloola from which this species was first originally described no longer supports the species.
As a result of the BANQ surveys of Kalkadoon and Carpentarian Grasswren habitat in 2008-9 the Carpentarian Grasswren is now classified as "Vulnerable" and the Kalkadoon as "Of Least Concern". In the Northern Territory the Carpentarian Grasswren is classified as "Endangered" with good reason.
DERM has given us permission to publish the report on the 2011 Survey carried out on Carpentarian Grasswrens at Boodjamulla National Park. You can download the report here as a pdf file, size 2MB, or by clicking on the image on the left.
It is clear that the main threat to the species is inappropriate burning of the Spinifex habitat. The project has now entered the monitoring phase. The initial strategy is to prepare maps of burning over the last ten years and look at the difference in burning patterns in areas where they have done well and where they have disappeared. In this way we can construct an index of fire challenge to the species. There will be more field surveys when we have a better understanding of this relationship with fire.