The Australian Government, in partnership with the NSW Office of Environment and Heritage, the Queensland Department of Environment and Heritage Protection and the Victorian Department of Sustainability and Environment, facilitates the publication of recovery plans to detail the actions needed for the conservation of threatened native wildlife.
The attainment of objectives and the provision of funds may be subject to budgetary and other constraints affecting the parties involved, and may also be constrained by the need to address other conservation priorities. Approved recovery actions may be subject to modifications due to changes in knowledge and changes in conservation status.
OEH 2012. National Recovery Plan for Eastern Bristlebird Dasyornis brachypterus. Office of Environment and Heritage, Department of Premier and Cabinet (NSW), Sydney.
This recovery plan was prepared by the NSW Office of Environment and Heritage with financial support from the Australian Government to be adopted as a national recovery plan under the provisions of the Commonwealth Environment Protection and Biodiversity Conservation Act 1999.
Prepared in accordance with the Commonwealth Environment Protection and Biodiversity Conservation Act 1999, the New South Wales Threatened Species Conservation Act, 1995, the Queensland Nature Conservation (Wildlife) Regulation 2006, and the Victorian Flora and Fauna Guarantee Act, 1988.
ISBN: 978 1 74232 836 2
Table of Contents Executive Summary 1
Species Information 3
Conservation Status 3
Species Description 5
Distribution and Populations 6
Life History 15
Habitat Clearing 18
Habitat disturbance by exotic herbivores 21
Habitat degradation due to dieback or invasive weeds 21
Small sub-populations and genetic bottlenecks 22
Climate Change 22
Human disturbance 23
Recovery Information 24
Previous Recovery Actions 24
Recovery Objectives 27
Recovery Actions 28
Estimated Costs for Recovery Actions 42
Management Practices 44
Affected Interests 44
International Obligations 46
Biodiversity Benefits 46
Indigenous Interests 48
Socio-Economic Impacts 50
Appendix 1 67
Executive Summary The Eastern Bristlebird (Dasyornis brachypterus) is listed as ‘Endangered’ in Australia under the Commonwealth Environment Protection and Biodiversity Conservation Act 1999 and under state legislation in Queensland, New South Wales (NSW) and Victoria. The species is also listed as ‘Endangered’ by the International Union for Conservation of Nature (IUCN). The northern population of the Eastern Bristlebird meets the criteria for ‘Critically Endangered’ by the IUCN.
The Eastern Bristlebird is a small, brown, well-camouflaged, ground-dwelling bird. It is generally shy and cryptic, spending most of its time in low, dense vegetation and rarely appearing in the open or flying. The species has contracted to four genetically isolated populations in three disjunct areas of south-eastern Australia: south-eastern Queensland/north-eastern NSW (northern population), the Illawarra and Jervis Bay regions of eastern NSW (central populations) and the NSW/Victorian border coastal region (southern population). Each of the geographically separate regional populations is comprised of one or more disjunct local populations or colonies.
Limited evidence suggests that Eastern Bristlebirds in the northern population are morphologically distinct from the more southerly populations. Northern birds have previously been considered a distinct sub-species, Dasyornis brachypterus monoides, while central and southern populations comprise the nominate sub-species Dasyornis brachypterus brachypterus. However, recent genetic analysis does not support sub-speciation.
The total national population of the Eastern Bristlebird is estimated at approximately 2500 birds, with two populations of around 1000 individuals. Population estimates should be recalculated with updated vegetation mapping and results of standard census techniques.
The Eastern Bristlebird inhabits a broad range of vegetation communities with a variety of plant species compositions that are generally defined by a similar structure of low, dense, ground or understorey vegetation. The species occupies fire-prone habitats and its response to fire is highly variable, however, the Eastern Bristlebird is particularly vulnerable to large-scale, intense fires. The extent, intensity and frequency of fires are all important in determining habitat suitability, along with the presence of unburnt refuges.
The main threat to the Eastern Bristlebird is the loss or fragmentation of suitable habitat, which can be caused by inappropriate fire regimes and clearing for urban or agricultural development. Habitat loss is recognised as the main process that has reduced the distribution and abundance of the Eastern Bristlebird in the last 150 years. Predation is a potential threat to the species, particularly by feral predators and particularly after fire. Other threats include habitat degradation from feral animals and livestock and invasion of weeds, genetic bottlenecks and inbreeding, climate change and human disturbance.
The long-term objective of this Eastern Bristlebird recovery program is the stabilisation of all populations. This will involve enhancing the northern population to a viable size, maintaining the stability of the central populations, and establishing an additional southern population in Victoria, bringing the size of the southern population to a viable level. Viable population size will be determined by population viability analysis (PVA). Attaining this long-term objective will involve the protection and management of habitat, the management of threats and enhancement of wild populations through captive breeding, augmentation and reintroduction. The objectives, criteria and actions proposed in this recovery plan work towards that objective and build on those in previous plans.
Actions required for the recovery of the Eastern Bristlebird include: survey, monitoring and mapping of all populations and habitat; maintenance or improvement in the condition and extent of habitat; management of threats, including fire, feral predators, exotic herbivores, weeds, genetic bottlenecks and climate change; enhancement of the northern and southern populations to viable levels; research to improve knowledge of the species; effective coordination of the recovery effort; improved communication between stakeholders and community involvement. The estimated total cost of implementing recovery actions is $3,609,000 over the five years of this plan.
SPECIES INFORMATION Conservation Status
The Eastern Bristlebird (Dasyornis brachypterus) is listed as ‘Endangered’ in Australia under the Commonwealth Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act). It is listed as ‘Endangered’ in Queensland (Nature Conservation (Wildlife) Regulation 2006, Schedule 2, subordinate legislation to the Nature Conservation Act 1992 (NC Act)); ‘Endangered’ in New South Wales (Schedule 1 of the Threatened Species Conservation Act 1995 (TSC Act)); and ‘Threatened’ in Victoria (Schedule 2 of the Flora and Fauna Guarantee Act 1988 (FFG Act)) (DSE 2010) where it is also classified as ‘Endangered’ (DSE 2007).
The Eastern Bristlebird is listed as ‘Endangered’ on the International Union for Conservation of Nature (IUCN) Red List of Threatened Species because of its small range and severely fragmented populations and sub-populations.
The northern population of the Eastern Bristlebird also meets the criteria for ‘Critically Endangered’ under the IUCN (IUCN 1994) categories of threat (criteria A1+2bc, B1+2bde, C2a, D).
The ancient origins of the Eastern Bristlebird can be dated back to Gondwanaland (Christidis and Norman 2010).
The bristlebirds have traditionally been placed in the family Acanthizidae which includes the scrubwrens, thornbills and gerygones. This family has its greatest diversity in Australia, Papua New Guinea and nearby islands. Schodde and Mason (1999) considered the closest relative to the bristlebirds to be the Pilotbird (Pycnoptilus floccosus). However, most recent texts have placed the bristlebirds in a separate family (Dasyornithidae) (Dickinson 2003; Gill and Wright 2006; Gregory 2006; Christidis and Boles 2008) and recent research supports this separation (Gardner et al. 2010).
Within the Dasyornithidae there are three bristlebird species within a single genus: Eastern (Dasyornis brachypterus), Rufous (D. broadbenti) and Western (D. longirostris). The Eastern and Western Bristlebirds are the two species most closely related and in the past have been treated as one species (Keast 1957). All three species are endemic to Australia, similar in appearance and inhabit temperate habitats along the southern and south-eastern coastal and subcoastal regions of Australia (see Figure 1). They have all declined in both distribution and abundance and are threatened with extinction.
The Eastern Bristlebird is confined to three regions in south-eastern Australia. Recent genetic investigations (Roberts et al. 2011) have concluded that there are four distinct populations or management units: one northern, two central and one southern, which will be discussed more fully in the Distribution section. Limited evidence suggests that Eastern Bristlebirds in the northern population are morphologically distinct from the two more southerly populations. Northern birds appear to be larger and have brighter plumage (Chaffer 1954) and make bulkier nests (Holmes 1989) than southern birds. Schodde and Mason (1999) found several consistent but subtle plumage differences between the northern population and the central and southern populations, and proposed that the northern population should be recognised as a distinct sub-species with the name Dasyornis brachypterus monoides. They also proposed that the central and southern populations comprise the nominate sub-species Dasyornis brachypterus brachypterus.
Figure 1. Current distribution of the three bristlebird species. This separation into sub-species is not supported by available genetic data (Elphinstone,2008; Roberts et al. 2011. The Action Plan for Australian Birds (Garnett et al. 2011) notes this, yet nevertheless ‘recognises’ the split proposed by Schodde and Mason (1999). However, the separation into subspecies has no formal status under state or Commonwealth legislation.
Species Description The Eastern Bristlebird is a small, well-camouflaged, ground-dwelling bird. It is dark cinnamon-brown above, with pale colouring around the eyes and base of the bill, an off-white chin and throat, and a rufous-brown panel on each wing. It is greyish-brown below, with an off-white centre to the belly. It has red to red-brown irises, an off-white to pinkish-white gape, and pinkish-brown legs and feet (Higgins and Peter 2002).
Body length is between 18 and 21 centimetres (Higgins and Peter 2002) with the broad tail accounting for about half the bird's length. Adults weigh approximately 42 grams (range 35-50 g) (Baker 1998; Bramwell 1990; Higgins and Peter 2002). The wings are small (23 to 24 cm wingspan) and the legs are long and strong. The sexes are alike, but females are slightly smaller than males (Bain 2007). Juveniles are similar to the adults, but can be identified, if viewed at close range, by their pale brown or brown irises, and pale yellow gape (Higgins and Peter 2002).
The species spends most of its time in low, dense vegetation, rarely appearing in the open or flying. Due to its small wings the Eastern Bristlebird flies weakly, but sturdy feet and legs help it move through dense habitat. While plumage provides excellent camouflage, other adaptations to its habitat include a low forehead profile with bristles near the eyes. The rictal bristles which project from the beak are modified contour feathers that are thought to play a part in prey capture. The bristles may also provide protection for the bird's eyes as it consumes its struggling prey (Cornell Lab of Ornithology 2007). Another theory is that the bristles may function as sensors, providing tactile feedback, like the whiskers on a dog or cat (Lederer 1972) to facilitate obstacle avoidance. Other bird species are thought to benefit from elongated facial plumage that mechanically detects obstacles or provides protection for the eyes and face within dense or tangled habitat e.g. Manu Antbird (Cercomacra manu) or Whiskered Auklet (Aethia pygmaea) (Fitzpatrick and Willard 1990; Seneviratne and Jones 2008).
The Eastern Bristlebird is generally shy and cryptic. It usually occurs singly or in pairs, or rarely in small groups of three or four (Baker 1998; Chapman 1999). It is a terrestrial species and occasionally birds may be glimpsed scampering across openings or making low laboured flights of up to 20 metres. When disturbed or alarmed, a bird may move to a lookout perch a metre or more above the ground and call, then disappear into thick vegetation (Baker and Whelan 1996).
The Eastern Bristlebird has a distinctive call that is loud and melodic. 'Pretty birdie' (or variations) is the most characteristic call, although the presence of an Eastern Bristlebird is often signalled by an alarm call: a loud, strident 'prist' or softer 'chip'. Dueting and other calling interactions often occur. Using call playback to survey for cryptic, terrestrial birds, including the Eastern Bristlebird, is a method that has been used extensively and only about one quarter of the Eastern Bristlebirds detected by their calls are sighted (Baker 1992; Bramwell et al. 1992). However, some expertise is required to recognise calls and to distinguish them from the calls of other species such as Brown Thornbills (Acanthiza pusilla) and Pilotbirds (Pycnoptilus floccosus). The Eastern Bristlebird is less vocal outside the breeding season.
Distribution and Populations Historical Distribution
It is likely that changes in vegetation due to past climatic fluctuations and Aboriginal fire regimes had reduced the distribution of the Eastern Bristlebird to three isolated regions on the east coast of Australia prior to European settlement (Chisholm 1951; Keast 1957; Smith 1977). Last century, the species occurred in scattered and isolated local populations along the east coast from Conondale Range in south-eastern Queensland to Marlo in Victoria, with a number of populations located along the central coast of NSW from Sydney to Ulladulla (Baker 1998). Figure 2 shows the past and recent distribution of the Eastern Bristlebird.
Morton Nat. Park
Figure 2. Past (○) and recent (●) distribution of the Eastern Bristlebird
(based on Baker 1997). The northern population has undergone a dramatic population decline and range contraction (e.g. Holmes 1989, 1998; Sandpiper Ecological Surveys 2000b, 2003, 2005a, 2008). Historically the distribution of the northern population extended much further south, to the Dorrigo Plateau and possibly to Wootton near the Myall Lakes (Chisholm 1958; Holmes 1982, 1989). Eastern Bristlebirds have not been recorded in the Conondale Range for several years despite extensive searches in previously known territories and known and potential habitat by DEHP and BirdLife Australia/Birds Queensland. Local populations known to have become extinct include several sites at Main Range, Lamington NP and Border Ranges NP.
The southern population has also undergone a significant population decline and range contraction in Victoria. Surveys in the late 1990s failed to locate the species at nine confirmed former sites and two unconfirmed sites in Victoria (Baker 1998; Clarke and Bramwell 1998). There are historical records at scattered sites from the NSW border to near Lake Tyers (White 1915; Clarke and Bramwell 1998), unconfirmed reports from Wilsons Promontory and Tarwin Lower-Walkerville (Cooper 1975; Emison et al. 1987; Mitchell 1995), and subfossil deposits indicating that the distribution once extended west at least as far as Nelson in far south-western Victoria (Blakers et al. 1984; Baird 1992).
In the central populations, there are historical records of the species at several locations between Sydney and Ulladulla where the species is thought to now be extinct. Surveys since 1997 have failed to locate the species at many former sites in this area (e.g. Baker 1998).
Current Distribution and Abundance
Since European settlement, the distribution and abundance of the species has further declined due to extensive clearing and habitat degradation and it is now severely fragmented (Holmes 1989, 1998; Hartley and Kikkawa 1994; Baker 1997, 2009; Chapman 1999; Garnett et al. 2011). The Eastern Bristlebird’s current discontinuous geographic distribution is shown in Figure 2. The species has contracted to three disjunct regions of south-eastern Australia: southern Queensland/northern NSW, the Illawarra and Jervis Bay region (the stronghold of the species) and the NSW/Victorian border (see Figure 2). Each of the geographically separate regional populations is comprised of one or more disjunct local populations or colonies (Blakers et al. 1984; Holmes 1989, 1997; Stewart 1997, 1998; Baker 1998; Clarke and Bramwell 1998; Barrett et al. 2003).
The total national population of the Eastern Bristlebird is estimated at approximately 2500 birds – see Table 1 for population estimates. However, population estimates should be recalculated with updated vegetation mapping and results of standard census techniques (see Actions).
Sandpiper Ecological Surveys (2012); Whitby (2009); D Rohweder and D Stewart pers. comm. (2010)
Barren Grounds NR and Budderoo NP
Woronora Plateau (Cataract Dam)
Baker et al. (2012)
Bherwerre Peninsula (Jervis Bay NP, Booderee NP,
Baker (1997), N. Dexter pers. comm. 2010
Baker et al. (2012)
Red Rocks NR
Bain & McPhee (2005)
Nadgee NR, NSW
Croajingolong NP, Vic
L Evans pers. comm. 2012
Bramwell (2008, pers. comm. 2010)
Table 1. Distribution and abundance of the Eastern Bristlebird. The species' area of occupancy1, as defined by the IUCN (1994), is estimated to be less than 120 km² and in reality in the order of about 29 km² (Baker 1998). The extent of occurrence2 is estimated to be over 1100 km² (Garnett and Crowley 2000; Stewart 2001, 2006).
The Eastern Bristlebird mainly occurs within the national reserve system (Baker 1998; Clarke and Bramwell 1998; Holmes 1998; Stewart 2001, 2006), with some colonies on other tenures as discussed below.
The small size of the Eastern Bristlebird national population means that all extant populations are likely to be important to the long-term survival and recovery of the species. Approximately 90% of the national population occurs in the two central populations (Baker 1998; Roberts et al. 2011).
At <40 individuals, the northern population is of particular significance. As discussed previously, this population is considered Critically Endangered under IUCN criteria (see section 1).
All four populations occur in Important Bird Areas (IBAs) - sites recognised as internationally important for bird conservation and known to support key bird species (Dutson et al. 2009). IBAs are designated by Birdlife Australia (formerly Birds Australia) and have no legal implications. They are areas of high priority for conservation efforts and resources (Dutson et al. 2009). Figure 3 shows a map of Important Bird Areas and Eastern Bristlebird distribution - northern population: Scenic Rim IBA; central population Budderoo and Barren Grounds IBA and Jervis Bay IBA; and southern population: Nadgee to Mallacoota Inlet IBA.