Slender-billed thornbill explained

The slender-billed thornbill (Acanthiza iredalei) is a small bird native to Australia. It includes three sub-species:

• A. i. hedleyi
• A. i. iredalei
• A. i. rosinae

This thornbill can be found in shrublands and salt marshes, typically those around salt lakes or low heath on sand plains.^[1] It eats mostly insects and spiders captured in the shrubs of its habitat. It rarely feeds on the ground, preferring instead the higher elevations of shrubs and trees.^[1]

The slender-billed thornbill is rarely observed alone. They are usually seen in flocks of approximately eight birds or in pairs. Thornbill nests are small and built in low shrubs. They are constructed of grass, bark, cobwebs, and other shrubland debris. Females lay up to three eggs during the breeding season, which runs from July until November.^[1]

Description

The thornbill ranges from 9 to 10 centimeters in length. The colour of its back ranges from olive-grey to a darker olive-brown. The base of its tail is olive-yellow. Its underbelly is a smooth cream colour, and it has a dark bill and pale eyes.

Distribution and habitat

The slender-billed thornbill iredalei subspecies has six separate and isolated populations in Western Australia, and a large population in the Carnarvon bioregion.^[2] The hedleyi subspecies is found in southeastern South Australia and western Victoria, and the rosinae subspecies is most commonly found in the Gulf St Vincent region of South Australia.^[3]

Conservation status

The rosinae subspecies is considered vulnerable.^[4] The hedleyi subspecies is considered near threatened.^[4] The iredalei subspecies is also considered vulnerable.^[5]

The slender-billed thornbill (iredalei subspecies) is extinct in northern Australia, and is considered the only indigenous species to have become extinct in that region since European settlement.

Victoria

• The slender-billed thornbill (A. i. hedleyi) is listed as threatened on the Victorian Flora and Fauna Guarantee Act 1988.^[6] Under this Act, an Action Statement for the recovery and future management of this species has not been prepared.^[7]
• On the 2007 advisory list of threatened vertebrate fauna in Victoria, this species is listed as near threatened.^[8]

Notes and References

1. Web site: Threatened Species of the Northern Territory: Slender-Billed Thornbill . Northern Territory Government: Department of Land Resource Management . Chris . Pavey . Simon . Ward . December 2012 . 2015-09-10 . 2015-03-22 . https://web.archive.org/web/20150322135935/http://www.lrm.nt.gov.au/__data/assets/pdf_file/0019/10846/slender-billed-thornbill_VU_FINAL.pdf . dead .
2. The Directory of Australian Birds: Passerines by R. Schodde, I. J. Mason. Journal of Biogeography, Vol. 27, No. 3 (May, 2000), pp. 782-783
3. Morcombe, Michael (2012) Field Guide to Australian Birds. Pascal Press, Glebe, NSW. Revised edition.
4. http://www.birdsaustralia.com.au/ Birds Australia
5. Department of the Environment and Water Resources (2007). Acanthiza iredalei iredalei in Species Profile and Threats Database, Department of the Environment and Water Resources, Canberra. Available from: http://www.environment.gov.au/sprat.
6. Book: Advisory List of Threatened Vertebrate Fauna in Victoria . 2013 . Victoria Government: Department of Sustainability and Environment . Melbourne, Australia . 978-1-74287-504-0 . 13 . 10 September 2015 . dead . https://web.archive.org/web/20140203162740/http://www.depi.vic.gov.au/__data/assets/pdf_file/0019/210439/Advisory-List-of-Threatened-Vertebrate-Fauna_FINAL-2013.pdf . 3 February 2014 .
7. Web site: Flora and Fauna Guarantee Act: Action Statement Index by Category and Scientific Name . 2006-09-11 . dead . https://web.archive.org/web/20060911130015/http://www.dse.vic.gov.au/DSE/nrenpa.nsf/LinkView/617768308BCB666E4A25684E00192281E7A24BB36FF60A144A256DEA00244294 . 2006-09-11 .
8. Book: Victorian Department of Sustainability and Environment . Advisory List of Threatened Vertebrate Fauna in Victoria - 2007 . Department of Sustainability and Environment . 2007 . East Melbourne, Victoria . 15 . 978-1-74208-039-0 .