Thick-billed Grasswren

The Thick-billed Grasswren, known scientifically as Amytornis modestus, is a rather inconspicuous avian resident of Australia's shrubby landscapes. This bird is characterized by its dull brown underparts and a long, dark-brown tail. Its head is adorned with striking white streaks that extend down the neck, throat, and rump, creating a stark contrast against the red-brown to grey plumage. The males boast longer tails than their female counterparts, who can be distinguished by their chestnut flanks.

Identification Tips

When attempting to identify the Thick-billed Grasswren, look for the distinctive white streaks that run from the chin to the forehead and along the wings and rump. These markings are set against a backdrop of red-brown to grey feathers. The bird's vocals, a series of short, high-pitched songs, may aid in identification, though its soft, high-pitched calls are often beyond our auditory range.

Habitat

The Thick-billed Grasswren is a denizen of Mediterranean-type shrubby vegetation, with a particular fondness for dense chenopod bushes in lower-lying areas such as watercourses and drainage lines. These habitats include chenopod scrublands, sandhill cane-grass, and flood debris in dry, sandy watercourses.

Distribution

Endemic to Australia, this species is scattered across the arid regions of northwestern New South Wales, northern South Australia, and southern parts of the Northern Territory. There is speculation of fragmented populations in the Grey Range of Sturt National Park.

Behaviour

The Thick-billed Grasswren is a sedentary and elusive creature, often seen running or hopping between cover to avoid detection. Rarely taking to flight, these birds forage at ground level amidst vegetation. They are typically solitary or found in pairs, maintaining territories that range from five to 40 hectares. Family groups may be observed during the post-fledgling period.

Song & Calls

The Thick-billed Grasswren's vocal repertoire includes a short, high-pitched song that is repeated, and a soft call that is often inaudible to human ears.

Breeding

Breeding season spans from July to September. Nests are constructed in low branches of saltbush and similar vegetation, forming a half-dome of loose grass and bark, lined with finer materials. Clutches typically consist of one to three eggs, which are white, cream, or pink with red-brown or purplish grey blotches. Incubation lasts two weeks, with fledging occurring in 10-12 days.

Diet and Feeding

The diet of the Thick-billed Grasswren includes insects, small invertebrates, plant seeds, and berries. Their thick bills enable them to access tougher seeds and a variety of food sources.

Conservation status

The Thick-billed Grasswren faces threats from habitat loss due to clearing and overgrazing by livestock, as well as predation by feral species like foxes and cats. High-frequency bushfires and droughts have further impacted their habitat. The species is listed as "Least Concern" by the IUCN but is considered vulnerable or critically endangered under various regional legislations. A 2018 study highlighted the species as one of the Australian birds most at risk of extinction.