Data Zone
Justification of Red List category
This species has undergone rapid declines exceeding 50% over the last three generations primarily as a result of severe fire and drought. As a result, it is classified as Endangered.
Population justification
In 1979–1983, A. r. rufescens occupied about 730 territories (Ferrier 1984) or 1460 mature individuals, and A. r. ferrieri occupied about 1,720 territories or 3,440 mature individuals. Based on the impacts of drought and fire, the population of A. r. rufescens is estimated to have declined by 64% (49%–67%) in the last decade with declines greatest at Main Range (est. 2020 population: 2 birds; loss 86%) and Gibraltar Range (170, 82%); losses at Lamington (220, 30%) and in the Border Ranges (140, 29%) almost entirely a consequence of drought, so may be cyclic. The population of A. r. ferrieri is estimated to have declined by 56% (43%–60%) with losses greatest at Hasting Range (est. 2020 population 460, loss 74%), lower at Ebor/Dorrigo (550, 18%) and least at Barrington Tops (510, 2%). As a result, the best estimate is now 2,050 individuals for the species (Stewart et al. 2021, Stuart et al. 2021).
Trend justification
The population of the species is probably less than half what it was a decade ago as a result of drought and fire. In 1979–1983, A. r. rufescens occupied about 730 territories (Ferrier 1984) or 1460 mature individuals, which was thought not to have changed by 2010 based on observations of Ekert (2005) and Hill (2010). Based on annual monitoring of the A. r. ferrieri at Barrington Tops area (Stuart 2020), which is consistent with observations in the Border Ranges (Hill 2010; 2018) and Lamington National Park (Stewart 2018), populations are assumed to have been 29% lower than Ferrier (1984) in 2019 because of drought. Fire in 2019 reduced this further; based on its severity in the areas occupied by the scrub-birds and estimates of mortality at different severity classes (severity class 2: 20%; class 3: 50%; class 4: 100%; class 5: 100%), about 49% of the population probably died in the fire, with estimates ranging from 28% to 54% depending on the fire-related mortality assumed under different scenarios. Including population reductions resulting from drought, the population is estimated to have declined by 64% (49%–67%) in the last decade with declines greatest at Main Range (est. 2020 population: 2 birds; loss 86%) and Gibraltar Range (170, 82%); losses at Lamington (220, 30%) and in the Border Ranges (140, 29%) almost entirely a consequence of drought, so may be cyclic. In burnt areas, the lower quality of damaged habitat may mean losses are continuing among survivors. In 1979–1983 A. r. ferrieri occupied about 1720 territories (Ferrier 1984) or 3440 mature individuals. On the basis of the area above 600 m, this would have been about 1790 at Hastings Range, 910 at Ebor/Dorrigo and 740 Barrington Tops. Since then, reasonable numbers occurred at Werrikimbie and Carrai National Parks with smaller numbers at other sites in 1999–2004 (Ekert 2005), and densities above 1100 m on Barrington and Gloucester Tops in September 2010 were about 6 pairs/km2 (Newman and Stuart 2011), suggesting little change at that time (Garnett et al. 2011). Subsequent annual monitoring at Barrington Tops suggested that densities were exceptionally high following wet conditions in 2010 and 2011, relatively stable 2012–2016 with densities similar to those estimated by Ferrier (1984), then fell from 3.7 pairs/km2 to 2.6 pairs/km2 from 2017–2019 as a result of drought (Stuart 2020). As dry conditions were pervasive across the subspecies range, the population in 2019 is assumed to have been 29% lower than Ferrier (1984) at about 2400. Fire in 2019 reduced this further; based on its severity in the area occupied by the scrub-birds and estimates of mortality at different severity classes (severity class 2: 20%; class 3: 50%; class 4: 100%; class 5: 100%), about 37% of the population died in the fire, with estimates ranging from 20% to 44% depending on the fire-related mortality assumed under different scenarios. Including population reductions resulting from drought, the population is estimated to have declined by 56% (43%–60%) with losses greatest at Hasting Range (est. 2020 population 460, loss 74%), lower at Ebor/Dorrigo (550, 18%) and least at Barrington Tops (510, 2%). The lower quality of damaged habitat may mean losses continued among survivors.
Atrichornis rufescens occurs in isolated populations in north-eastern New South Wales and south-eastern Queensland, Australia. A. r. rufescens occur in high rainfall areas in north-east New South Wales and south-east Queensland (Schodde and Mason 1999), now mostly in areas above 600 m as a result of the clearing of lowland habitat (Ferrier 1984). There are four subpopulations: Border Ranges (Border Ranges National Park), Gibraltar Ranges (Gibraltar Ranges and Barool National Parks), the northern part of the McPherson Range (Lamington National Park west to Mount Barney National Park) and in the Main Range (upper reaches of Dalrymple Creek, Mount Cordeaux, Mount Mitchell and Cunninghams Gap). There have been no recent records from other historical sites in the region this century. Fires in late 2019 burnt 37% of all 1x1 km squares from which birds have been recorded since 1990, mostly in the Main and Gibraltar Ranges with the largest subpopulations on the Lamington Plateau and Border Ranges largely unaffected (G Ehmke unpublished). A. r. ferrieri occur in high rainfall areas along the Great Dividing Range in north-central New South Wales (Schodde and Mason 1999). Known subpopulations are centred on Barrington Tops, including Gloucester Tops, the Hastings Range including Werrikimbie National Park, and the Dorrigo and Ebor Plateaus in New England National Park. Most occupied areas are above 600 m (Ferrier 1984). There were records from all areas in the last decade but no comprehensive on-ground surveys since the 2019 fires. A lowland record from near Wauchope (Boles and Tynan 1995) suggests birds may once have moved between what are now disjunct upland habitat patches. Fires in late 2019 burnt 52% of all 1x1 km squares from which birds have been recorded since 1990, mostly in the Hastings Range, where the largest subpopulation occurred, with some burnt on the Dorrigo and Ebor Plateaus and almost none at Barrington Tops (G Ehmke unpublished).
A. r. rufescens are now confined to subtropical, warm temperate and cool temperate rainforests above 600 m with dense ground cover, often including areas regenerating from fires or storms. They forage on small invertebrates, including snails and insects on the ground and over fallen logs, amongst leaf-litter and on other ground vegetation and debris, within the dense understorey, and lay two eggs in loosely-built domed nests situated in dense vegetation close to the ground (Higgins et al. 2001). Very little is known of their breeding behaviour because they are so shy and cryptic, living in dense vegetation. A. r. ferrieri currently occur in cool moist and wet eucalypt forests above 600 m, usually close to temperate rainforests, where they forage for small invertebrates amongst leaf-litter and on other ground vegetation where there is dense ground cover which includes ecotones, forested watercourses and wetlands, and areas regenerating from fires or storms. They lay two eggs in domed nests built close to the ground (Higgins et al. 2001). Each male sings over an area of about a hectare (Stuart 2018), and seemingly good territories can remain empty for several years after a known male disappears, suggesting that there are few floating males in the population (Stuart 2019). It can take at least six years after fire before habitat regains suitability (Stuart and Newman 2018).
The major threat is fire, as demonstrated by the fires of 2019–2020, in association with longer and hotter droughts (Ferrier 1984). Fire is normally rare in rainforest but so severe and hot was the drought in 2019 that rainforest burnt, if patchily. Some disturbance does appear to benefit birds if there is strong regrowth of low vegetation, but the scale of recent burning was unprecedented, and recovery is likely to be slow. Both heat and drought are likely to increase in frequency and intensity (Evans et al. 2017, Herold et al. 2018), as will extreme fire weather (Di Virgilio et al. 2019, Dowdy et al. 2019). The size and habitat are likely to make the species vulnerable to cat Felis catus predation (Woinarski et al. 2017). Most of the bird’s lowland habitat was cleared in the 19th century, and, while clearance itself is not a continuing threat with almost all birds being in protected areas, the subdivision of a small population into even smaller fragments makes each subpopulation more susceptible to random events. There has also been an unexplained retreat of the southern part of the population to higher altitudes, even from uncleared forest, and this may be related to drying caused by climate change; this appears to be continuing and occurring throughout the range. Breeding behaviour was shown to be affected by dry conditions in the breeding season (Newman et al. 2014). In the southern part of the range there has been increased clustering of territories over the last 30 years, suggesting that the habitat is less uniformly suitable. In the longer term, the viability of some small remaining subpopulations may be questionable.
Conservation Actions Underway
Listed as threatened under appropriate legislation. Negotiations are ongoing with Forests New South Wales to improve the protection of Rufous Scrub-bird habitat during logging and burning events (M. Newman in litt. 2016). Some monitoring has been initiated in four areas (Stuart et al. 2012, Newman et al. 2014).
Text account compilers
Berryman, A., Vine, J.
Contributors
Andren, M., Baker, B., Ford, H., Garnett, S., Holmes, T., Watson, D., Woinarski, J.C.Z., Stuart, A. & Newman, M.
Recommended citation
BirdLife International (2024) Species factsheet: Rufous Scrub-bird Atrichornis rufescens. Downloaded from
https://datazone.birdlife.org/species/factsheet/rufous-scrub-bird-atrichornis-rufescens on 23/11/2024.
Recommended citation for factsheets for more than one species: BirdLife International (2024) IUCN Red List for birds. Downloaded from
https://datazone.birdlife.org/species/search on 23/11/2024.