|Yellow thornbill (Acanthiza nana)|
Vigors & Horsfield, 1827
14, see text.
Acanthiza is a genus of passeriform birds, most endemic to Australia, but with two species (A. murina and A. cinerea) restricted to New Guinea. These birds are commonly known as thornbills. They are not closely related to species in the hummingbird genera Chalcostigma and Ramphomicron, which are also called thornbills.
They are found primarily in Australia and have a thin long beak. Colloquially the thornbill is sometimes referred to as a “tit” by locals, but in reality the Australian continent lacks any true tits, albeit Acanthiza species do show some similarities with tits in their behavior. They have a similar role as small insect-eating birds with titmice and kinglets. Like tits, Thornbills live in small groups foraging amidst trees and shrubs, and feed in a similar manner. Cooperative breeding is recorded from most species except the brown and Tasmanian thornbills.
The habitat preferences of the group vary from dense forest to open saltbush and bluebush plains.
Acanthiza follow a very characteristic undulating path when flying. Their diet is formed essentially of little insects and plant lice that these birds glean from foliage. They are also exceptional acrobats that are easily able to stay head downward like tits do.
The nest of the Acanthiza is a large dome-shaped construction, completely enclosed except for a side hole, just like that of the long-tailed tit; however Acanthiza adds to it an additional room whose function is unknown. It is somewhat similar to the Aegithalidae in combining long incubation periods with highly synchronous hatching. This combination, normally impossible due to intense competition for food, occurs because parents and (usually) helpers can organise food supply in such a manner that sibling competition for food is virtually absent.
The number of eggs usually ranges from two to four, and the incubation period is around twenty days with laying intervals of two days. The length of an adult bird is 8 to 10 centimetres (3.1 to 3.9 in).
The genus contains 14 species:
- Mountain thornbill, Acanthiza katherina
- Brown thornbill, Acanthiza pusilla
- Inland thornbill, Acanthiza apicalis
- Tasmanian thornbill, Acanthiza ewingii
- New Guinea thornbill, Acanthiza murina
- Chestnut-rumped thornbill, Acanthiza uropygialis
- Buff-rumped thornbill, Acanthiza reguloides
- Western thornbill, Acanthiza inornata
- Slender-billed thornbill, Acanthiza iredalei
- Yellow-rumped thornbill, Acanthiza chrysorrhoa
- Yellow thornbill, Acanthiza nana
- Grey thornbill, Acanthiza cinerea
- Striated thornbill, Acanthiza lineata
- Slaty-backed thornbill, Acanthiza robustirostris
- Bell, Harry L.; Ford, Hugh A. (1986). "A Comparison of the Social Organization of Three Syntopic Species of Australian Thornbill, Acanthiza" (PDF). Behavioral Ecology and Sociobiology. 19 (6): 381–92. doi:10.1007/bf00300540. JSTOR 4599974.
- Higging, P.J. and J.M. Peter; Handbook of Australian, New Zealand and Antarctic Birds, vol. 6: Pardalotes to Shrike-thrushes. ISBN 0-19-553762-9
- Ricklefs, R.E.; “Sibling competition, hatching asynchrony, incubation period, and lifespan in altricial birds”; in Power, Dennis M. (editor); Current Ornithology. Vol. 11. ISBN 9780306439902
- Losdat, Sylvain, Helfenstein, Fabrice, Gaude, Benoît and Richner, Heinz; “Effect of sibling competition and male carotenoid supply on offspring condition and oxidative stress”
- Ricklefs, Robert E.; “SIBLING COMPETITION AND THE EVOLUTION OF BROOD SIZE AND DEVELOPMENT RATE IN BIRDS”
- Gill, Frank; Donsker, David, eds. (2019). "Bristlebirds, pardalotes, Australasian warblers". World Bird List Version 9.1. International Ornithologists' Union. Retrieved 21 January 2019.
- Del Hoyo, J.; Elliot, A. & Christie D. (editors). (2006). Handbook of the Birds of the World. Volume 12: Picathartes to Tits and Chickadees. Lynx Edicions. ISBN 978-84-96553-42-2
- Acanthiza fotos & videos on the Internet Bird Collection