Atrichornis clamosus 

Scope: Global
Language: English

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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Aves Passeriformes Atrichornithidae

Scientific Name: Atrichornis clamosus (Gould, 1844)
Common Name(s):
English Noisy Scrub-bird, Noisy Scrubbird, Western Scrubird
Spanish Corredor Chillón
Taxonomic Source(s): Christidis, L. and Boles, W.E. 2008. Systematics and Taxonomy of Australian Birds. CSIRO Publishing, Collingwood, Australia.
Identification information: 22-26 cm. Skulking passerine with short, rounded wings, long, rounded tail and characteristically triangular head profile. Adult dark brown above with faint dark barring and contrasting rufous wings. Grey-brown below merging to rufous on vent and undertail-coverts and cream on lower breast. Male has diagnostic blackish triangle on throat with bold whitish stripes at sides. Female has whitish throat. Juvenile unbarred above with rich, buff foreneck and breast. Similar spp. Western Bristlebird Dasyornis longirostris lacks dark barring and has pale scallops on back and breast. Voice Male calls powerful, penetrating and directional. Main territorial song highly variable within and between individuals; generally a sweet, descending crescendo, falling and accelerating into ear-splitting climax.

Assessment Information [top]

Red List Category & Criteria: Endangered B1ab(i,ii,iii,v)+2ab(i,ii,iii,v) ver 3.1
Year Published: 2016
Date Assessed: 2016-10-01
Assessor(s): BirdLife International
Reviewer(s): Butchart, S. & Symes, A.
Contributor(s): Burbidge, A.H., Garnett, S. & Comer, S.
Facilitator/Compiler(s): Benstead, P., Dutson, G., Garnett, S., Harding, M., McClellan, R., Symes, A., Taylor, J. & North, A.
Despite several decades of intensive conservation work, which resulted in a population increase, large lightning-induced fires have since caused significant further declines in population size and habitat quality, from which any recovery is likely to be slow. These declines, additional unexplained smaller-scale declines infer a continuing decline in habitat quality and number of mature individuals, and as it also has a very small range and is restricted to just five locations, it has been uplisted to Endangered.

Previously published Red List assessments:

Geographic Range [top]

Range Description:Atrichornis clamosus is found on the south coast of Western Australia, Australia. Between 1961, when it was rediscovered, and 1976, it was largely confined to the Mt Gardner area of the Two Peoples Bay Nature Reserve, 40 km east of Albany. As a result of translocations, and recolonisation from the Mt Gardner population, the range has since increased (Comer 2002). Natural colo­nists and translocations have created one extensive subpop­ulation at a handful of locations from Two Peoples Bay to Cheyne Beach, as well as an introduced population at Bald Island (59 calling males in 2004 [A. Burbidge in litt. 2004], increasing to 99 territorial males in 2010 [Garnett et al. 2011]), and a reintroduced population near Drakesbrook, the type locality, south of Perth. However, breeding near Drakesbrook has not been confirmed, despite the reintroduction of 100 individuals (S. Garnett in litt. 2004, Garnett et al. 2011). In the Albany management area, the number of singing males increased from 569 in 1999 to 733 in 2001 (Comer 2002, Garnett et al. 2011). However, a series of fires in the Two Peoples Bay-Manypeaks area between December 2000 and December 2004 reduced the number of singing males to c.278 in 2005, with a small increase to 370 in 2006 (A. Burbidge in litt. 2007, Garnett et al. 2011)The last full census was completed in 2011, when 503 singing males were recorded.  Since then the monitoring of specific sub-populations have recorded declines (Mt Gardner) and increases (Bald Island).  Further fires in 2015 and early 2016 have impacted the population on Mt Gardner and the western end of Manypeaks (S Comer in litt. 2016).

Countries occurrence:
Additional data:
Estimated area of occupancy (AOO) - km2:140Continuing decline in area of occupancy (AOO):Yes
Extreme fluctuations in area of occupancy (AOO):NoEstimated extent of occurrence (EOO) - km2:6800
Continuing decline in extent of occurrence (EOO):YesExtreme fluctuations in extent of occurrence (EOO):No
Number of Locations:5Continuing decline in number of locations:Unknown
Extreme fluctuations in the number of locations:No
Upper elevation limit (metres):500
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:The population was estimated at c.1,500 breeding birds by Garnett and Crowley (2000), however a series of fires in the Two Peoples Bay-Mt Manypeaks area between December 2000 and December 2004 has severely impacted this, the species's largest, subpopulation (A. Burbidge in litt. 2007), and further fires in 2015 impacted on the population at Two Peoples Bay Nature Reserve (S Comer in litt. 2016).  Its population is now estimated to number 1,000-1,500 mature individuals, roughly equivalent to 1,500-2,300 individuals in total.

Trend Justification:  A combination of translocation and habitat management efforts have resulted in local increases, but fire events have resulted in substantial declines in the largest subpopulation. The species may recover from such fires, although it may take ten years before the habitat is suitable (Danks and Comer 2006), and in combination with additional unexplained smaller-scale declines a probable continuing decline in the number of mature individuals at an unknown rate is inferred (Garnett et al. 2011).
Current Population Trend:Decreasing
Additional data:
Number of mature individuals:1000-1500Continuing decline of mature individuals:Yes
Extreme fluctuations:NoPopulation severely fragmented:No
No. of subpopulations:2Continuing decline in subpopulations:Unknown
Extreme fluctuations in subpopulations:NoAll individuals in one subpopulation:No
No. of individuals in largest subpopulation:1-89

Habitat and Ecology [top]

Habitat and Ecology:Its preferred habitat contains dense clumps of sedges, shrubs or piles of debris for nesting cover, interspersed with small, open areas with a thick accumulation of leaf-litter and a well-developed litter fauna for feeding (Danks et al. 1996). It mainly eats terrestrial arthropods (Danks and Calver 1993). Most occupied sites have not been burnt for at least 10 years, the sites on Mt Gardner having a post-fire age of over 50 years, and on Bald Island of over 120 years (Garnett et al. 2011). Some sites on Mt Manypeaks that were burnt in 2004 had been recolonised by 2006, but only in areas where the fire was less severe and vegetation regeneration has been rapid (A. Burbidge in litt. 2007). Historically, the species may have occu­pied the ecotone between swamp vegetation and forest dominated by Jarrah Eucalyptus marginata and Marri E. calophylla (Smith 1985), although such habitat is rare within the species’s current range. It apparently disperses along corridors of closed vegetation. It crosses roads readily, although not cleared land.

Systems:Terrestrial; Freshwater
Continuing decline in area, extent and/or quality of habitat:Yes
Generation Length (years):5
Movement patterns:Not a Migrant

Threats [top]

Major Threat(s): The historical disappearance of the species from most of its former range has been attributed to changes in fire regime following the disruption of Aboriginal fire management before the 1880s. In 1976, the single, remnant population survived in an area protected from fire by the terrain. The frequent burning of swamps to make them more suitable for cattle-grazing, as well as their drainage and clearance for horticulture, would have had major impacts. Extensive high-intensity bushfire is the major current threat, the species depends on long unburnt habitat and has limited dispersal abilities. In 1994, a fire at Mt Taylor destroyed most of a recently translocated population, with remaining birds disappearing within the subsequent year. The largest subpopulation was formerly on Mt Manypeaks, following a remarkable recovery since translocations began in 1983, however in summer 2004/2005, a fire there burnt a 4,500 ha block of habitat (Comer and Burbidge 2006), amounting to the loss of one third of the suitable habitat for the species in the Albany area (Danks and Comer 2006). Surveys in 2005 revealed a 55.6% reduction in the number of singing males in the Albany Management Zone compared to numbers in 2001, largely as a result of the loss of birds from within the burnt area at Mt Manypeaks (Danks and Comer 2006), with the loss of almost all of the birds (c.1,000) in the 427 territories counted in 2001 (Comer and Burbidge 2006) Post-fire monitoring in 2011 found small numbers of birds had recolonised some of the gullies that had experienced rapid post-fire regrowth on Mt Manypeaks, and breeding was confirmed through locating active nests.  Further fires in 2015 and early 2016 impacted on occupied habitat between Mt Manypeaks and Two Peoples Bay, and Mt Gardner (the original parent population) where over 90% of known habitat was lost (S. Comer in litt. 2016). Almost all birds are now on protected land, but habitat clearance on private land could cut corridors, fragmenting populations and preventing dispersal. Breeding success is relatively good, but various native and introduced mammals and reptiles may raid nests and kill adults (Danks et al. 1996), and evidence for predation by feral cats was confirmed by the discovery of a scrub-bird feather in the stomach of feral cat trapped on Mt Gardner (DPaW, 2014).

Conservation Actions [top]

Conservation Actions: Conservation Actions Underway
CITES Appendix I. The species has undergone 50 years of intense research, monitoring and management, including protection from fire and translocation. The population at Mt Manypeaks was established following translocations in 1983 and 1985 (Comer 2002, Comer and Burbidge 2006). Following a fire at Mt Manypeaks a project was started in March 2005 to begin long-term monitoring of the species's recovery, including studies on invertebrate food resources and the vegetation associated with its habitat, as well as increased fox control, cat trapping and improved fire management capabilities (Danks and Comer 2006). Between June and August 2006, eight males were translocated from the Mermaid-Waychinicup area to karri forest in Porongurup National Park, and fitted with radio transmitters during the process (Anon. 2007). Radio-tracking proved unsuccessful (Berryman 2007), but call monitoring was carried out (Anon. 2007, Berryman 2007), revealing that one male moved 1.2 km from the release site (Berryman 2007). In 2008, following a fire that burnt through the park, only one male from the translocation was still being heard (Tiller 2009) and this bird had disappeared by 2009. Similarly translocations took place in Gull Rock National Park in 2007 but only one bird could be located the following year (Tiller 2009). The search for potential translocation sites continued and in 2010, following significant pre-translocation work,  a small group of six scrub-birds (5M:1F) were released as a trial in Jane National ParkTwo of the males were predated days after being released. No birds were found in 2011. The recovery of this species is being managed by the South Coast Threatened Birds Recovery Team (A. Burbidge in litt. 2007).

Conservation Actions Proposed
Establish populations where appropriate habitat persists throughout its former range. Maintain active fire protection and habitat management at all sites. Survey and monitor all known populations at five-year intervals. Continue to support coordination of management by the South Coast Threatened Birds Recovery Team.

Citation: BirdLife International. 2016. Atrichornis clamosus. The IUCN Red List of Threatened Species 2016: e.T22703612A93929997. . Downloaded on 25 May 2018.
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