Gilbert's whistler
| Gilbert's whistler | |
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Scientific classification 
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| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Aves |
| Order: | Passeriformes |
| Family: | Pachycephalidae |
| Genus: | Pachycephala |
| Species: | P. inornata
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| Binomial name | |
| Pachycephala inornata Gould, 1841
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The Gilbert's whistler (Pachycephala inornata) is a monotypic species of bird endemic to Australia, scattered in semi-arid zones of southern Australia.[2][3]
Taxonomy
The family Pachycephalidae originated within the Australo-Papuan region.[3][4] Together with the red-lored whistler and the olive whistler, the Gilbert's whistler is basal to the genus Pachycephala – the typical whistlers.[3][4] This old monotypic lineage represents a relictual form that was once more widespread.[3]
John Gould, who first described this species in 1841, named it after Mr Gilbert who discovered the bird in Western Australia and collected specimens that he handed over to Gould.[5] As for its scientific name – Pachycephala inornata – in Ancient Greek pachys and kephale respectively mean ‘thick’ and ‘head’; several of the members of the genus Pachycephala are indeed called ‘thickheads’, and other common names for the Gilbert's whistler include black-lored Gilbert thickhead, red-throated thickhead, Gilbert's thickhead, or simply thickhead.[2] With ‘inornatus’ meaning ‘plain’ in Latin, the second part of its binominal name is attributed to the Gilbert's whistler's plumage, which is often described in the literature as being plain.
There are several entries in the GenBank DNA sequence database for Pachycephala inornata.[6]
Description
The adult male, which weighs 29.8-32.5 g,[2] possesses a rufous-coloured chin and throat[2][7][8][9][10] from its third year of life,[2] as does its most likely closest relative,[4] the red-lored whistler. Both males can easily be differentiated by the colour of their lores: black for the Gilbert's and red for the red-lored whistler. The female Gilbert's whistler (23.5-32.2 g) has a pale grey throat and a white ring around the eye; her underparts can be lightly streaked.[2][9] Both sexes are uniformly brownish-grey, and have a red iris and a black stubby bill (17–18 mm).[2][9] Juveniles (30.9 g) are darker than adults, with tinges of brown, and have dark streaks on the breast and belly.[2][9] Immatures are very similar to adult females except for their brown bill and dark brown iris.[2] Care should be taken not to mistake the female and immature Gilbert's whistler for the female golden or western whistlers where they co-exist.[2]
At one stage, the Gilbert's whistler was divided into two subspecies: Pachycephala inornata inornata to the east of the Flinders Ranges with greyish white underparts, and Pachycephala inornata gilberti in the west with cinnamon and buff underparts;[11] this variation is now considered clinal.[2]
A study undertaken by Onley, Gardner and Symonds (2020) on possible larger appendages in whistlers caused by climate change (Allen's rule) from museum specimens collected between 1915 and 2013, found an increase in the body size of the Gilbert's whistler at higher latitudes, following Bergmann's rule.[12]
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Ecology
Diet
Gilbert's whistlers feed mostly on the ground,[2] as does about half of all declining species of birds in southern Australia.[13] This species also forages in understorey layers.[2] They feed primarily on invertebrates, although fruit and seeds can also form part of its diet.[2]
Nesting and clutch
Gilbert's whistlers erect a deep
Vocalisations
All whistlers are songsters, and the Gilbert's whistler, in particular, is more often heard than seen.[9] Its loud, melodious and clear call can be heard at distances up to 900 m,[2] mostly during the breeding season[9] when it establishes a breeding territory.[2] Its song is described as a series of swelling cheop, cheop, cheop repeated five to 20 times,[9] with another ascending call er-WHIT, er-WHIT, er-WHIT[16] similar to the rufous whistler,[9] and also a more scratchy call eechowk, eechOWK, eeCHOWK.[17]
Habitat, distribution and threats
The Gilbert's whistler inhabits semi-arid tall mallee with sparse shrubby understorey or prickly Acacia thickets and Casuarina woodlands, and is also found in thickets of Melaleuca and, occasionally, in taller eucalypt woodlands or forests.[2][4][8] A study undertaken in 2017 on the effect of bushfires and prescribed burns on the distribution of 12 threatened bird species predicted that habitat burnt between 30 and 60 years approximately would be favoured by Gilbert's whistlers while habitat burnt more frequently or not burnt for more than 60 years would not readily suit this species.[18]
The
Conservation
Of the four states in which the Gilbert's whistler occurs, this species is listed as vulnerable only in
The Gilbert's whistler is not listed at national level under the Environment Protection and Biodiversity Conservation Act 1999,[22] and is listed as least concern at international level under the IUCN Red List of Threatened Species 2016.[23]
Gallery
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Bird skin specimen, Gilbert's whistler (Pachycephala inornata) (Gould, 1844) -
Male Gilbert's whistler (Pachycephala inornata) -
Female Gilbert's whistler (Pachycephala inornata)
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References
- . Retrieved 16 November 2021.
- ^ a b c d e f g h i j k l m n o p q r s t u v w Higgins, P. J. and Peter J. M. (Eds.) (2002). Handbook of Australian, New Zealand and Antarctic Birds. Volume 6: Pardalotes to Shrikethrushes. Melbourne: Oxford University Press. pp. 1096–1100.
- ^ PMID 24403319.
- ^ S2CID 85013290.
- ^ Gould, Elizabeth; Gould, John; Richter, Henry Constantine (1840). The birds of Australia. Vol. 2. London: Printed by R. and J. E. Taylor; pub. by the author.
- ^ "pachycephala inornata - Nucleotide - NCBI". www.ncbi.nlm.nih.gov. Retrieved 2021-06-03.
- ^ a b "Gilbert's Whistler | BirdLife Australia". www.birdlife.org.au. Retrieved 2021-06-03.
- ^ a b c d "Gilbert's Whistler - profile | NSW Environment, Energy and Science". www.environment.nsw.gov.au. Retrieved 2021-06-03.
- ^ a b c d e f g h i Menkhorst, P., Rogers, D., Clarke, R., Davies, J., Marsack, P., Franklin, K. (2017). The Australian bird guide, Whistlers. Clayton South, VIC: CSIRO Publishing. pp. 476–481.
{{cite book}}: CS1 maint: multiple names: authors list (link) - ^ a b Pizzey, G and Knight, F. (2013). Birds of Australia, Digital edition. Gibbon Multimedia.
{{cite book}}: CS1 maint: multiple names: authors list (link) - ISSN 0158-4197.
- ISSN 0024-4066.
- ISSN 1035-3712.
- ISSN 0158-4197.
- ^ a b Hunt, Anthony; Ewin, Peter; Clayton, Mark (2018). "An example of a "Twinkling Lights" local extinction event: population dynamics of Gilbert's Whistler at The Charcoal Tank Nature Reserve, New South Wales". Corella. 42: 42–49.
{{cite journal}}: CS1 maint: multiple names: authors list (link) - ISSN 0158-4197.
- OCLC 27621009.
- .
- ^ Reid, J. R. W. (2000). Threatened and declining birds in the New South Wales Sheep-Wheat Belt: II. Landscape relationships – modelling bird atlas data against vegetation cover. Consultancy report to NSW National Parks and Wildlife Service. Canberra: CSIRO Sustainable Ecosystems.
- ISSN 0067-2238.
- ^ "Gilbert's Whistler (Pachycephala inornata) | Conservation project | NSW Environment, Energy and Science". www.environment.nsw.gov.au. Retrieved 2021-06-04.
- ^ Environment, jurisdiction=Commonwealth of Australia; corporateName=Department of the. "Threatened Species List". www.environment.gov.au. Retrieved 2021-06-04.
{{cite web}}: CS1 maint: multiple names: authors list (link) - ^ BirdLife International (2016-10-01). "IUCN Red List of Threatened Species: Pachycephala inornata". IUCN Red List of Threatened Species. Retrieved 2021-06-04.