Inland Thornbill

Identification

The inland thornbill is very similar to the brown thornbill (A. pusilla) in appearance, and these two species are sometimes considered conspecific. The brown thornbill is slightly smaller than the inland thornbill at approximately 10 cm (3.9 in) compared to 11.5 cm (4.5 in). The inland thornbill has white speckling on the forehead, while the brown thornbill has rufous speckling and is less grey than the inland thornbill. Range and habitat is the easiest way to differentiate these two species. Where both species occur in eastern Australia, the inland thornbill can be found in drier habitats than the brown thornbill; however, in southwestern Western Australia (outside of the brown thornbill’s range) inland thornbill can be found in wetter forests.<p>Gould originally described the inland thornbill as having a larger and rounder tail, a broad and distinct band of black tipped with white across the ends of the tail feathers, and a larger overall size than other Acanthiza species. The inland thornbill has several calls similar to the brown thornbill and a high-pitched tsee-tsee. Inland thornbills have also been found to be proficient in mimicking the calls of other birds, such as the pied butcherbird (Cracticus nigrogularis), rufous whistler (Pachycephala rufiventris), bush stone-curlew (Burhinus grallarius), willie wagtail (Rhipidura leucophrys), grey fantail (Rhipidura albiscapa), and various cuckoos.<p>Inland thornbills are long-lived, with one instance of the same bird being retrapped and banded over seven years after the first occasion. A typical lifespan for an inland thornbill is 5.7 years.

Taxonomy

Early classification of the Acanthiza, or thornbill genus, was inconsistent with the currently accepted taxonomy.  Historically, researchers recognised 10 -17 species in 1 – 3 genera. Separate traditional species of Thornbill have now been more accurately classified as subspecies than discrete species; however, the evolutionary relationships between inland thornbills and other Acanthizae are complicated. For example, the relationship between the inland thornbill and the brown thornbill (A. pusilla) and the mountain thornbill (A. katherina) is more complex than just classifying the genus. To further complicate the evolutionary relationships between species in the genus Acanthiza, two species exist outside of Australia in New Guinea. The New Guinea thornbill (A. murina) is found in the highlands of New Guinea, and it is not definitive how this species fits in with the classification of other thornbills. Still, some research has found the New Guinea thornbill to be closely related to A.nana or the yellow thornbill. Traditionally Acanthiza classification was conducted using morphology and plumage patterns.<p>Recent research using base-substitution data from nuclear DNA (nDNA) sequences sampled from Acanthiza species identified five separate species groups. Inland thornbills are in the same species group as A, pusilla, A. ewingii, and A. katherina. The other species groups are one containing A. inornate, A. uropygialis, A, reguloides, and A. iredalei, one containing A. nana and A. lineata, one containing A. chrysorrhoa, and one for A. robustirostris. The results of the Acanthizae nDNA samples were compared to samples from the gerygone, whiteface and weebill genera, as these species have previously been found to be in the same tribe as Acanthiza.<p>There are four recognised subspecies of inland thornbill with different geographic regions:

Scientific name

Acanthiza apicalis

Authority

Gould, 1847

Order

Passeriformes

Family

Acanthizidae

Genus

Acanthiza

Range and habitat

Migration

Resident species

Behavior

Migration pattern: Resident species.

Conservation

Population trend: declining.

Population trend

declining