White-throated Grasswren

The white-throated grasswren is the largest member of the Australian grasswrens (Amytornis spp.), with a wing length of 70–80 mm. It has a similar pattern of coloration to the smaller Carpentarian grasswren (A. dorytheae), which occurs on sandstones hundreds of kilometers to the east of the Arnhem Plateau. White-throated grasswrens have a typically dark plumage with a striking white 'bib' from below the chin to the middle of the belly. Females tend to have dark reddish brown flanks and lower belly, whereas males have lighter rufous brown belly and flanks. White-throated grasswrens have soft, high-pitched contact calls that sound very similar to the co-occurring purple-backed (lavender-flanked) fairywren (Malurus assimilis dulcis), but also produce a complex song of trills and warbles.

The white-throated grasswren is only found on and around the Arnhem Land sandstone massif, between Katherine and Maningrida; representing an area of 6,200 km2 (2,400 sq mi). Like most grasswren species, the white-throated grasswren nests in large clumps of sharply pointed spinifex grass, which provides protection from predators. Its natural habitats are sandstone and conglomerate escarpment of the Arnhem Plateau. Ecological niche modelling has shown that white-throated grasswrens typically occupy habitat patches that are close to unburnt habitat, have a low proportion-of-area-burnt, have low vegetation cover, and high time-since-fire, particularly when compared to the average background values across the landscape. Using rough high and low thresholds of ecological niche modelling suitability scores, researchers predict that there is currently somewhere between 536 km2 and 2631 km2 of suitable habitat for the species. This is substantially less than previous estimates for the species. Local knowledge by Bininj Nawarddeken people has identified sightings of the white-throated grasswren near outstations in the Warddeken Indigenous Protected Area, including Manmoyi, Kamarrkawarn, and Kabulwarnmyo in place where 'karri kore kanjdjikandji, ankebkakebkali', translating to 'the river by the edge of the rocks where they meet the savanna'.

The bird, known as Yirlinkirrkirr in the local Bininj Kunwok language, is of cultural significance to the Nawarddeken people.