The bristlebirds are a family of passerine birds, Dasyornithidae. There are three species in one genus, Dasyornis. The family is endemic to the south-east coast and south-west corner of Australia. The genus Dasyornis was sometimes placed in the Acanthizidae or, as a subfamily, Dasyornithinae, along with the Acanthizinae and Pardalotinae, within an expanded Pardalotidae, before being elevated to full family level by Christidis & Boles (2008).
Taxonomy and systematics
Taxa accepted or described by Schodde & Mason (1999) include, with their estimated conservation status:
Once placed within various Northern Hemisphere lineages (such as Old World warblers or Old World flycatchers), the Dasyornithidae's closest relatives are now known to be Australian endemics such as the pardalotes and honeyeaters. Although their exact position within the Australasian basal lineages of passerines is not fully resolved, Marki et al.’s 2017 study, the first to sample and sequence molecular data for all three species of bristlebirds, placed them within the ecologically diverse infra-order Meliphagides (formerly known as Meliphagoidea). This lineage consists of five families: Maluridae (fairywrens and allies), Acanthizidae (thornbills and gerygones), Meliphagidae (honeyeaters), Pardalotidae (pardalotes) and Dasyornithidae (bristlebirds). While other families within this grouping are highly speciose e.g. the Meliphagidae (honeyeaters) with 187 species, Dasyornis broadbenti, D. brachypterus and D. longirostris are only three known species of bristlebirds. Marki et al. found strong support for D. broadbenti as sister lineage to D. brachypterus and D. longirostris, having diverged from its relatives in the mid-Miocene ca.13 Mya and that D. brachypterus and D. longirostris diverged in the early Pliocene, ca. 5 Mya. They infer from this that genetic divergences within the family may be greater than their similar morphologies might suggest and urge denser sampling to explore the possibility of overlooked cryptic species.
Description
Bristlebirds are long-tailed, sedentary, ground-frequenting birds. They vary in length from about 17 cm to 27 cm, with the Eastern bristlebird the smallest, and the Rufous bristlebird the largest, species. Their colouring is mainly grey with various shades of brown, ranging from olive-brown through chestnut and rufous, on the plumage of the upperparts. The grey plumage of the underparts or the mantle is marked by pale dappling or scalloping. The common name of the family is derived from the presence of prominent rictal bristles – three stiff, hair-like feathers curving downwards on either side of the gape. This feature distinguishes them from the scrub-birds, to which they are similar in appearance although not closely related. The bristles, which are conspicuous in many birds that like the bristlebirds forage for insects in dark locations, may serve a tactile function in locating or manipulating prey.
Distribution and habitat
Eastern bristlebirds were first seen by Europeans in Port Jackson (Sydney Harbour) when Latham first described the species for science in 1801. According to Gould, they were "to be found throughout New South Wales in all places suitable to its habits, although, from the recluse nature of its disposition, it is a species familiar to few, even of those who have long been resident in the colony." After two centuries of European colonisation, two of the three species of bristlebirds are endangered (see Status and Conservation), and all have restricted and disjunct ranges. Their distributions are non-overlapping, with the Western bristlebird, inhabiting a tiny area of dense heathland on the south-west coast of Western Australia, the most specialised. On the east coast, the Eastern bristlebird occupies a wider range of habitats in relict pockets of far south-east Queensland and northern New South Wales, and coastal fringes south of Sydney to the Victorian border. The Rufous bristlebird's range is dense coastal shrub and heathland in far south-west Victoria and extreme east South Australia. The least-shy member of the family, the newly discovered subspecies caryochrous, occurs in open eucalyptus forest with dense understorey in the Otway range, but is also found in car parks, tracks and gardens along the edges of its dense habitat. Gould's description of the Eastern bristlebird's habitat as "reed-beds and thickets, particularly such as are overgrown with creepers and vegetation" captures the density of coastal heath scrub and grasslands favoured by the Dasyornithidae, although not the fire-dependence of these environments, which require burning to prevent the trees shading out the grass component.