The Kalkadoon Grasswren has had a checkered taxonomic history. It was originally described as an outlying easterly population (subspecies ballarae) of the Western Grasswren (Amytornis textilis), and its similarities to the central Australian population of that species (subspecies purnelli) were recognized at that time. In 1972 Parker took a closer look at these birds and split the ballarae and purnelli races off as a separate species, the Dusky Grasswren (Amytornis purnelli). Again, the subtle, but significant, differences between purnelli and ballarae were recognized, and Schodde (1982) thought they should be considered separate species. That became a reality in 1999 when Amytornis ballarae was formally recognized as a stand-alone species by Schodde and Mason. This decision has subsequently been validated by molecular studies (summarized by Christidis et al., 2013).
As far as grasswrens go, the Kalkadoon Grasswen is relatively easy to observe in the rocky and spinifex-clad hillsides in the Mount Isa area (Harrington et al., 2017), but, interestingly, it was only described in 1969. Despite this comparatively recent date, it was the first species of grasswren reported from Queensland, when Bill and Helen Horton (former Birds Queensland members; Bill a former President) observed grasswrens near the (now abandoned) Ballara Mine between Mount Isa and Cloncurry in 1966. Shortly afterwards, Condon described the bird as A. t. ballarae based on two females collected on Ballara Station by RK Carruthers. The following year, Carruthers, Horton and Don Vernon (Queensland Museum and another BQ Council member) described the male and made some observations on the natural history of the birds. The name Kalkadoon is a reference to the traditional owners of the land on which the species is found.
Kalkadoon Grasswrens favour steep rocky hillsides and nearby slopes with boulders and abundant spinifex, and any habitat of this nature within approximately 100-150km of Mt Isa is worth inspecting if you are interested in seeing the species. As with any grasswren, an ability to hear high-pitched sounds is extremely useful in tracking the birds down. Fire is the greatest threat to the security of these birds. The grasswrens avoid areas for the first three years after a burn, and favour spinifex that has not been burnt for at least 10 years (Harrington et al., 2017). It is the only grasswren species over most of its range, apart from a small area in the northwest where it overlaps with the Carpentarian Grasswren. The overall brown appearance of the Kalkadoon distinguishes it from the Carpentarian which has a white throat and breast. As with a number of other grasswren species, the female has a distinct rufous patch on its flanks, which is missing in the male.
Of all the grasswrens, the Kalkadoon remains one of the least known biologically. This seems somewhat surprising as it is one of the few grasswren species that is found close to a significant population centre (Mt Isa). Its relatively recent recognition as a separate species and the few resident birders in the Mt Isa area have limited opportunities to get to know this bird better. Nevertheless, it is an appealing subject for more intensive investigation, and BirdLife Australia’s Northern Queensland group has an ongoing monitoring program for the species.
The Kalkadoon Grasswren shares many characteristics with the Dusky Grasswren (and other grasswren species), although the two species do show certain plumage differences and have distinct calls. It is very much earth-bound, and runs or hops along the ground when not perched on rocks or the low branches of shrubs. It is reluctant to fly, and when it does, it is usually downhill when escaping from danger. Consistent with their terrestrial habits, all grasswrens have a relatively wide pelvis and poorly developed breastbone. Correspondingly, their flight muscles are much reduced, but their thigh muscles are quite bulky. Like most grasswrens, the Kalkadoon feeds on insects and seeds, and possibly fruit, but no detailed studies have been carried out. It is usually found in pairs or small groups, and sometimes singly (e.g. Harrington et al., 2017).
The Kalkadoon Grasswren breeds mainly between August and October, but there are also reports of breeding during Summer. The nest is compact domed structure made from grass stems, usually with a prominent hood over the entrance. It is usually located in a spinifex clump or low bush. Of the grasswren species that have been studied in detail (but not the Kalkadoon) the female alone builds the nest. Typically, two or three eggs are laid, but there is no information available on the incubation time. It appears that only the female carries out incubation (although more observations are needed), but both parents feed the nestlings and remove faecal sacs. Cooperative breeding is possible, as multiple adult birds have been observed near a nest with recently hatched young.
If you have not yet enjoyed an encounter with one of Australia’s remarkable grasswrens, then the Kalkadoon Grasswren is a good species to get you on your way.
Sources
- Black A, Gower P. 2017. Grasswrens. Australian Outback Identities. Axiom, Adelaide.
- Carruthers RK, Horton W, Vernon DP. 1970. Distribution, habits and sexual dimorphism of the Western Grass-wren Amytornis textilis ballarae Condon in north-western Queensland. Mem Qld Mus 15: 335-341.
- Christidis L, Rheindt FE, Boles WE, Norman JA. 2013. A re-appraisal of species diversity within the Australian grasswrens Amytornis (Aves: Maluridae). Australian Zoologist 36: 429-437.
- Condon HT. 1969. A new subspecies of the Western Grass-wren, Amytornis textilis (Dumont) in north-western Queensland. Mem Qld Mus 15: 205-206
- Harrington G, McKeown A, Venables B. 2017. The range and habitat of the Kalkadoon Grasswren Amytornis ballarae. Australian Field Ornithology 34:12-17.
- Higgins PJ, Peter JM and Steele WK (eds). 2001. Handbook of Australian, New Zealand and Antarctic Birds. Volume 5. Tyrant-flycatchers to Chats. Oxford University Press. Melbourne.
- Parker SA. 1972. Remarks on distribution and taxonomy of the Grass Wrens Amytornis Textilis, Modestus and Purnelli Emu 72: 157-166.
- Rowley I, Russell E. 1997. Fairy-Wrens and Grasswrens. Oxford University Press.
- Schodde 1982. The Fairy-wrens: A Monograph of the Maluridae. Lansdowne Editions, Melbourne.
- Schodde R and Mason IJ. 1999. The Directory of Australian Birds. Passerines. CSIRO, Melbourne.
