Grass Wrens

Last updated: Friday 27 May, 2016

Amytornis genus – grasswrens in Australia

Australian grasswrens are small birds with a big reputation. The 11 species of the Amytornis (grasswren) genus are somewhat of a mystery.

Why? They live in remote areas, they’re elusive, small and have well-camouflaged plumage that helps them remain undetected.

A Western Grasswren on Hamelin Station Reserve. Photo Ben Parkhurst.
A Western Grasswren on Hamelin Station Reserve. Photo Ben Parkhurst.
Their call is soft, high-pitched and hard to hear. What’s more, some species are becoming increasingly rare. Little wonder they fascinate bird enthusiasts across Australia.  

Grasswrens are generally small birds (though larger and more robust than Fairy-wrens). The Eyrean Grasswren is the smallest of the species, measuring between 14 and 16.5 cm long. Their colours vary: their plumage can be rufous, brown, black, grey and white. Streaked patterns are common, helping them to camouflage in their habitat – both birdwatchers and predators find them difficult to spot!

Their short beak is perfectly suited for crushing seeds. Their tail is often long, slender and elevated.

All species have short, rounded wings, so they can't undertake long flights. Instead, they hop, run, bound or bounce between bushes and tussocks of grass. The white-throated grasswren is said to ‘hop and scuttle rat-like between rocks and clumps of vegetation’!

Where do Grasswrens live?

Grasswrens are endemic to (only found in) Australia and many species have a very limited range. Most species are found in arid areas in continental Australia, but there are also three tropical species.

A Western Grasswren on Hamelin Station Reserve. Photo Ben Parkhurst.
A Western Grasswren on Hamelin Station Reserve. Photo Ben Parkhurst.
In the north, the Carpentarian Grasswren inhabits the hilly parts of north-western Queensland eastern Northern Territory; the White-throated Grasswren lives in north-western Arnhem Land; Dusky Grasswrens are found in the arid interior (NT, WA and SA) and the Black Grasswren lives in the Kimberley region of Western Australia. 

South Australia boasts a number of Grasswrens, including the Short-tailed Grasswrens found in the Flinders, Gammon and Gawler Ranges, and the Thick-billed Grasswrens that inhabit saltbush country of the South Australian rangelands.

Other inland grasswrens include the Grey Grasswren found near the Queensland/NSW and Queensland/South Australia borders. The Eyrean Grasswren lives in the canegrass on dunes in the eastern and southern Simpson and Strzelecki Deserts across South Australia, Queensland and the Northern Territory. The Kalkadoon Grasswren lives in north-western Queensland. The Western Grasswren is limited to the Shark Bay region of Western Australia (it once occurred across a much larger area of the state) and in South Australia it occurs on the Eyre peninsula in chenopod shrubland. Finally, the Striated Grasswren has the most widespread – albeit fragmented – range of the grasswrens, including arid and semi-arid inland areas of all continental states and territories. 

Under the IUCN Red List of Threatened Species, the Carpentarian Grasswren and the White-throated Grasswren are listed as vulnerable to extinction; the Black Grasswren and Short-tailed species are near threatened; and the remainder are of Least Concern.

However many of these classifications are difficult to make, given the cryptic nature of the birds: for instance while the Eyrean grasswren was first described by western scientists in 1875, the next reliable sighting occurred in 1961! 

Behaviour/ ecology

As their name suggests, many of these grasswrens live in and eat grass. Grasswrens are omnivorous: they eat seeds, fruits, insects and other invertebrates. They forage on the ground for their fare, never far from a clump of grass or a shrub, where they can quickly bound away to safety.

In terms of reproduction, many inland species respond to ‘boom and bust’ conditions of the arid interior. Their life-expectancy is uncertain, though some Grey Grasswrens are known to live at least three years. 

Threats

A major threat to grasswrens is habitat loss due to changed fire regimes. The birds are also hit hard by over-grazing from stock and feral animals, which reduces the availability of food, cover and nesting sites.

In addition to habitat loss and degradation these impacts can lead to habitat fragmentation, which is particularly devastating for these little birds as they can't fly long distances between remaining patches of habitat. Without dense thickets and clumps of grass, grasswrens are forced to spend more time in open areas, making them more vulnerable to feral cats. 

What's Bush Heritage doing?

You can see grasswrens flit around many Bush Heritage reserves and partnership properties. There are Black Grasswrens on Wunambul Gamberra country, White-throated Grasswrens on Warddeken country, Eyrean Grasswrens on Ethabuka in Queensland, and in South Australia there are Thick-billed Grasswrens on Bon Bon and Western Grasswrens are on Boolcoomatta as well as Hamelin Station in WA. 

We protect these species by: destocking properties and promoting regeneration of the shrubs and grasses that the wrens love; by controlling feral cats; and by restoring traditional burning techniques, which help prevent devastating late dry season wildfires.

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