Once, this well-camouflaged wren, bigger and sturdier than its Fairywren cousins, would have been found across much of south-western Australia.
However, a reduction in viable habitat due to overgrazing by rabbits and goats plus predation by feral cats saw its range gradually shrink westwards, and today, the Hamelin and Francois Peron birds are the only two remaining populations of the western subspecies, Amytornis textilis textilis.
It’s this element of mystery that initially attracted Aline to her PhD topic.
“You look at the literature and there’s so much on Fairywrens and then Grasswrens almost nothing,” she says. “They’re really cryptic…and there isn’t much known about their biology so there is no point of reference for planning a translocation.”
Over the past two years, Aline has spent many months in the field at Hamelin and Francois Peron mist netting, banding individual birds, collecting DNA samples, doing nest counts and recording vocal displays; building, block-by-block, a complete Western Grasswren data set.
The analysis of this data won’t be complete until Aline finishes her PhD but initial observations provide a fascinating insight into the bird’s behaviour, including the intriguing question of song dialect.
Understanding whether the Hamelin and Francois Peron birds recognise each other’s calls is important to the success of their eventual translocation to Dirk Hartog Island.
As Bush Heritage senior ecologist and one of Aline’s project supervisors Dr Michelle Hall puts it:
“Will the birds consider each other the same - will it be like a super sexy French accent - or will they think the other bird’s call sounds terrible and not be interested?”
“[Translocation] is already such a stressful situation… so you don’t want the birds to have new neighbours that they perceive as really aggressive,” Aline adds. “That’s something to consider in the release design – should we release all the Hamelin birds together and the Peron birds somewhere else? Over time they would mix but the initial placement could be separate.”
To test this, the songs of 19 different male Western Grasswrens from Francois Peron were played back to birds at Hamelin. The same experiment was repeated at Francois Peron with Hamelin songs.
“At times I saw the birds approach the speakers straight away, so upset about the rival intruding on their territory,” Aline says. “Other times I’ve seen them approach, but no singing, so they’re vigilant but not willing to engage. Some of them go immediately back to their original behaviours while others stay alert for a lot longer.”