EN
Western Bristlebird Dasyornis longirostris



Justification

Justification of Red List Category
This species has been uplisted to Endangered because it has a very small range, and a small population which is undergoing a decline, owing mainly to the effects of wildfires. Large lightning-induced fires in 2005 and 2006 severely reduced the population, and ongoing habitat degradation from fires is likely.

Population justification
In 2005, the known breeding population was estimated at 300-450 pairs, probably equating to a total of 1,000 mature individuals (A. Burbidge in litt. 2007, Garnett et al. 2011).

Trend justification
At the turn of the century, the species was considered to be stable; however, a series of fires in the Two Peoples Bay-Mt Manypeaks area between December 2000 and December 2004 impacted the local population (A. Burbidge in litt. 2007). Numbers of calling males were reduced from about 500 in 2001 to 200 in 2005, with similar numbers recorded in 2006. Thus, overall, the population is estimated to have declined over the last three generations.

Distribution and population

Dasyornis longirostris was formerly found in coastal south-west Western Australia, Australia, from Perth to Ravensthorpe. It is now restricted to 14 sites in and around Fitzgerald River National Park and to a small area just east of Albany at Two Peoples Bay Nature Reserve, Betty’s Beach, Mt Manypeaks to Bluff Creek. Eighteen birds were translo­cated in 1999–2000 and 2007 from Two People’s Bay to near Walpole, west of Albany, but there was no evidence of breeding. A population of c.620 pairs in 2001 was reduced by fires to c.320 pairs in 2005 (Burbidge et al. 2010), estimated to comprise c.1,000 mature individuals (Garnett et al. 2011). The density of birds is greater in the Manypeaks-Waychinicup areas than in the Fitzger­ald River National Park, but reasons for this are unknown. The Albany to Mt Manypeaks area population declined from c.500 pairs in 2001 to 200–315 pairs in 2005 and 2006, largely as a result of wildfires, although the cause for the decline in some areas is unclear. The Fitzgerald River National Park subpopulation numbered c.125 pairs in 2005 (Burbidge et al. 2010).

Ecology

It is terrestrial and sedentary with a preference for dense, low heaths. In Two Peoples Bay, it occurs in dense, closed heath 1-1.5 m high. Near Waychinicup River and in the Fitzgerald River National Park, it is found mainly in closed heath 0.5 m high, sometimes with scattered patches of mallee eucalypts. Unburnt swampy vegetation, predominantly sedges and thickets, may be important refuges after fires. At Two Peoples Bay, it can reoccupy heaths less than 3 years after fire, although breeding may not occur until later. It may not reoccupy heaths in drier areas until 11-14 years after fire. It was found in heaths 5-12 years after fire from Boulder Hill to east of Waychinicup River, and 14-28 years after fire in the northern part of Fitzgerald River National Park.

Threats

It is particularly vulnerable to habitat destruction and alteration. Wildfire is the principal threat, particularly large-scale wildfires, the incidence and extent of which have been increasing in recent years, despite increased skills, capacity and effort to stop them. Fires at less than 5-10 year intervals may lead to local extinctions, and such fires are almost certainly the main cause of its historical range contraction. At the other end of the scale, some coastal heath (at least at Two Peoples Bay) remains suitable habitat for at least 50 years after fire, although the carrying capacity may be reduced with time. A series of fires in the Two Peoples Bay-Mt Manypeaks area between December 2000 and December 2004 impacted the local population of this species (A. Burbidge in litt. 2007). Numbers of calling males were reduced from about 500 in 2001 to 200 in 2005 (A. Burbidge in litt. 2007). While most of this decline was clearly attributable to large-scale wildfires, some of the decline was most likely due to other, unknown factors (A. Burbidge in litt. 2007). Predation by introduced mammals, particularly foxes Vulpes vulpes and feral cats Felis catus, may be significant (Gilfillan et al. 2009; Burbidge et al. 2010). Other potential threats include dieback caused by the plant pathogen Phytophthora cinnamomi, disturbance by introduced animals (particularly hard-hoofed animals), weed invasion and changes in hydrological regimes (Gilfillan et al. 2009). Clearance for grazing and agriculture caused historical range contractions, but is no longer considered a threat as almost all bristlebirds now occur in protected areas.

Conservation actions

Conservation Actions Underway
CITES Appendix I. Surveys have been completed over the range of the species, and populations are protected from fire as much as possible, particularly in association with the other threatened taxa of the Two Peoples Bay-Manypeaks area. In 1999-2000 and 2007, 18 birds were translocated to a site west of Albany, but the translocation appears to have been unsuccessful and there was no evidence of breeding (Garnett et al. 2011). Further translocations are planned (A. Burbidge in litt. 2007). The population in the Two Peoples Bay-Mt Manypeaks area is being monitored (Danks and Comer 2006, A. Burbidge in litt. 2007). The recovery of this species is being managed by the South Coast Threatened Birds Recovery Team (A. Burbidge in litt. 2007).

Conservation Actions Proposed
Survey and monitor populations at five-year intervals and search for new subpopulations. Maintain active fire protection and management at all sites. Continue habitat management and threat abatement of all occupied areas within an adaptive management framework. Further investigate habitat requirements, in particular in relation to fire age, vegetation structure and food availability. Study the effect of dieback caused by Phytophthora cinnamomi, and the extent of predation by invasive species. Establish populations throughout former range where appropriate habitat persists. Continue the translocation programme. Continue to support coordination of management by the South Coast Threatened Bird Recovery Team (Garnett et al. 2011).

Identification

17-20 cm. Medium-sized, sturdy, grey-brown passerine. Sexes similar. Dark brown upper back dappled pale grey. Dark brown lower back. Rich rufous-brown rump. Rufous-brown upperwing-coverts. Mostly rufous-brown uppertail. Off-white centre of breast and belly with fine black-brown scalloping, sparser on belly. Olive-brown sides of belly and flanks with fine black-brown scalloping. Mostly olive-brown undertail. Juvenile similar to adult, but upperparts without dappling. Similar spp. Noisy Scrub-bird Atrichornis clamosus differs by having barred upperparts and lacking scalloping on underparts. Voice Male, high chortling call, very variable within and between individuals. Female, replying with a sharp, usually three-noted whistle.

Acknowledgements

Text account compilers
Benstead, P., Garnett, S., McClellan, R., Symes, A. & Taylor, J.

Contributors
Burbidge, A.


Recommended citation
BirdLife International (2019) Species factsheet: Dasyornis longirostris. Downloaded from http://www.birdlife.org on 26/03/2019. Recommended citation for factsheets for more than one species: BirdLife International (2019) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 26/03/2019.