Social organisation and breeding biology of the Western Grasswren (Amytornis textilis textilis)

ABSTRACT

Grasswrens (Amytornis) lack behavioural ecological studies despite many species having a declining population and threatened status. The Western Grasswren (Amytornis textilis) is a semi-arid passerine endemic to Western Australia (WA) and South Australia. This study aims to provide further knowledge about the social organisation and breeding biology of the WA subspecies (A. t. textilis) based on a colour-banded population over three years of monitoring. Western Grasswrens maintained territories in pairs, with occasional cooperative breeding facilitated by adult offspring of either sex who delayed dispersal. There was no evidence of divorce between breeding pairs. However, resighting of banded grasswrens was infrequent which may have biased this conclusion. Nest predation and abandonment events were lower than previously documented for this species. Offspring productivity was high, with >70% of the monitored groups producing at least one fledgling per year. Grasswrens used a range of substrates for nesting, but all had common structural features that likely aided in the concealment or thermoregulation of the nest. Social organisation and breeding biology were similar to what had been observed in two other grasswren species. This study has increased our understanding of a poorly understood cryptic species, and understudied genus, that can later be incorporated into future management strategies, population viability models and comparative analysis.

KEYWORDS:

• Behaviour
• breeding
• productivity
• reproduction
• songbirds

Acknowledgements

We acknowledge the Malgana and Whadjuk Noongar people as the Traditional Owners of the Land on which this research was conducted. We are grateful to Bush Heritage Australia for permitting work on Hamelin Station Reserve, and providing valuable in-kind support and collaboration in this study. Particular thanks go to M. and K. Judd at Hamelin Station Reserve for their technical support, and B. Parkhurst for sharing knowledge of grasswren locations. We thank the volunteers of the Wildflower Society of Western Australia for their assistance in some plant identifications. Finally, we are thankful for the field assistance provided by C. Greenwell, C. Bowry, J. Ringma, L. Louter, I. Pereda, R. de Visser, G. Blackburn, K. Rayner, B. Parkhurst, D. Goldspink, R. Quah, and G. Ricci.

Disclosure statement

No potential conflict of interest was reported by the author.

Ethics

Disturbance of Western Grasswrens was conducted under Department of Biodiversity, Conservation and Attractions (DBCA) license FO25000186 and FO25000287. Animal ethics approval was granted by DBCA (2019-05A) for Western Grasswren capture and banding. Grasswren monitoring was approved by the University of Western Australia (RA/3/100/1668). Mist-net and colour-banding was approved by the Australian Bird and Bat Banding Scheme (ABBBS authority: 3396 and 766, ABBBS project: 766-09).

Data availability statement

Data available through Figshare. https://doi.org/10.6084/m9.figshare.11880579.v2

Supplementary material

Supplemental data for this article can be accessed at https://doi.org/10.1080/01584197.2022.2125407

Additional information

Funding

This work has been generously supported by the Holsworth Wildlife Research Endowment, Wettenhall Environmental Trust and Paul Hackett Memorial project grants, alongside valuable funding from the Gorgon Barrow Island Net Conservation Benefits Fund. A. Gibson Vega is supported by an Australian Government Research Training Program scholarship through the University of Western Australia.