Tuesday, 22 August 2023
The Rockwarbler occurs only in New South Wales, and about 40 per cent of its habitat was burnt in the Black Summer bushfires that blazed across eastern Australia in 2019–20.
After the fires had passed, it was unclear how the Rockwarbler population had fared at their breeding sites, so BirdLife Australia established its Rockwarbler project, with volunteers conducting surveys to record their presence (or absence) across the Greater Sydney, Blue Mountains and Shoalhaven regions to help determine the effects of bushfires on the species.
Surveys were conducted at over 70 sites — both burnt and unburnt — within Rockwarbler habitat, and the birds were detected at 20 of them, with half the sightings in or near burnt habitat — the first records of the species at some sites for four years.
However, although preliminary results suggested that the species had been resilient in the wake of the Black Summer bushfires, more detailed analysis has revealed a small decline (but a statistically significant one nevertheless) in their reporting rate due to the fires. The analysis showed a decreased probability of detecting Rockwarblers in burnt sites after the fires, while over the same period Rockwarbler detections at unburnt sites remained about the same.
There were underlying spatial differences in habitat preference, highlighting the importance of controlling for both spatial and temporal variation when assessing impacts.
Despite the decline, its persistence in most burnt areas illustrates that the Rockwarbler has shown itself to be more resilient than some other species which were adversely affected by the Black Summer bushfires.
If you would like to take part in spring surveys of Rockwarblers, simply click here to register.
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