Current view: Data table and detailed info
Taxonomic source(s)
Christidis, L. and Boles, W.E. 2008. Systematics and Taxonomy of Australian Birds. CSIRO Publishing, Collingwood, Australia.
del Hoyo, J., Collar, N.J., Christie, D.A., Elliott, A., Fishpool, L.D.C., Boesman, P. and Kirwan, G.M. 2016. HBW and BirdLife International Illustrated Checklist of the Birds of the World. Volume 2: Passerines. Lynx Edicions and BirdLife International, Barcelona, Spain and Cambridge, UK.
IUCN Red List criteria met and history
Red List criteria met
Red List history
| Migratory status |
not a migrant |
Forest dependency |
low |
| Land-mass type |
Australia
|
Average mass |
- |
Population justification: The total population of D. b. brachypterus had previously been estimated at c.3,000 mature individuals (Bain et al. 2021), including 1,250 at Barren Grounds/Budderoo, 1,100 at Jervis Bay, 50 at Cataract, about ten at Red Rocks and 300 at Nadgee and Howe Flat (NESP TSRH 2019) with 140–160 birds at Howe Flat in 2020 (M. Bramwell unpublished; Clarke et al. 2020, Bain et al. 2021). An unknown number occur on the Beecroft Peninsula, but they are at all 40 monitoring sites established there (Lindenmayer et al. 2016). In 2020, 43 individual D. b. monoides were known to be alive in the wild, with another two sites having recent possible sightings, suggesting in total 45–46 birds were present (D. Charley unpublished, in Charley et al. 2021). Of these, four were confirmed in Queensland and 39 confirmed in NSW. The total number of D. b. monoides is therefore thought to be 25-40 mature individuals, with a best estimate of 30 (Charley et al. 2021). However, rapid declines in some populations have rendered some of these estimates no longer appropriate. Given a suspected decline of 30–49% of D. b. brachypterus reported at Barren Grounds/Budderoo and Nadgee/Howe Flat (but population stability at at least some other sites), the global population size is revised to 1,500-2,100 mature individuals, with a best estimate of 1,800.
Trend justification:
Until recently, the population of D. b. brachypterus at Nadgee had increased steadily to about 400 (NESP TSRH 2019) before fire in 2020 burnt most of the suitable habitat (Oliver & Malolakis 2020). Based on initial assumptions about mortality at different severity classes (severity low: 20%; medium: 50%; high: 100%; very high: 100%) and maps of fire severity, the fires killed an estimated 9% of the total population of D. b. brachypterus with estimates ranging from 5% to 11%, depending on the fire-related mortality assumptions adopted (G. Ehmke, S.T. Garnett unpublished, in Bain et al. 2021). Taken alone, the Nadgee population alone declined by 81% in one year (D. Bain in litt. 2022). Elsewhere in New South Wales, annual monitoring demonstrated steady increases at Cataract and Budderoo, probable increases at Beecroft Peninsula, stability at Jervis Bay and fluctuations at Barren Grounds (NSW OEH 2018, 2019). However, recent monitoring data suggest that these fluctuations at Barren Grounds/Budderoo are actually a decline: over the past three generations (12.9 years; Bird et al. 2020), the population has apparently declined by 78% from unknown causes (the area was not burned) (D. Bain in litt. 2022). This is equivalent to a loss of approximately 1,000 birds and is thought to have caused a c.32% decline in the global population if all other sites remained stable. Average densities of bristlebirds detected along transects in Booderee National Park during annual spring surveys since 2015 have been fairly constant across years, though with a sharp drop in 2018 followed by the highest density so far recorded in 2019 (Director of National Parks unpublished, in Bain et al. 2021). At Beecroft Peninsula, they were detected 337 times on 152 surveys, at least twice the detection rate of any other species except New Holland Honeyeaters Phylidonyris novaehollandiae, with effects of bombardment during military training having no impact on detection frequency (Lindenmayer et al. 2016). In Victoria, numbers at Howe Flat in 2008 (120–160; Bramwell 2008) differed little from those in 2020. Taking into account the losses in Nadgee following the severe 2019-20 bushfires and the reported declines from Barren Grounds/Budderoo, the total decline of D. b. brachypterus over the past three generations could be as high as 39–43%.
Numbers of D. b. monoides have been stable or slightly increasing in the last decade: in 2014, 11 birds were recorded, suggesting 13–30 birds present; in 2016, 18 birds were recorded (suggesting 20–30 birds present; NESP TSRH 2019); and in 2018, 25 birds were recorded suggesting 30–40 birds were present (D. Charley unpublished, in Charley et al. 2021). However, this was preceded by a long history of attrition: in 1988, 154 individuals were located in 103 territories; in 1996, there were 36 birds in 30 territories; in 1997–1998, there were 26 birds in 16 territories; and, in 2010, there were 25–30 individuals (Garnett et al. 2011).
Overall, the population is therefore suspected to have declined 30–49% over the past three generations based on the assumption that some unmonitored sites have remained stable. The principal cause of declines at Barren Grounds/Budderoo has not been identified and whether it is likely to continue in the future, or affect other sites (at least some of which have populations that have remained stable in the same time window) is wholly unknown.
Country/territory distribution
Important Bird and Biodiversity Areas (IBA)
Recommended citation
BirdLife International (2024) Species factsheet: Eastern Bristlebird Dasyornis brachypterus. Downloaded from
https://datazone.birdlife.org/species/factsheet/eastern-bristlebird-dasyornis-brachypterus on 23/12/2024.
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 23/12/2024.
