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.
Taxonomy The genus Acanthiza was introduced in 1827 by the naturalists Nicholas Vigors and Thomas Horsfield with Motacilla pusilla Shaw, the brown thornbill as the type species. The genus name combines the Ancient Greek ακανθα/akantha meaning "thorn" with ζαω/zaō "to inhabit" or "to live".
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.Higging, P.J. and J.M. Peter; Handbook of Australian, New Zealand and Antarctic Birds, vol. 6: Pardalotes to Shrike-thrushes.
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.Ricklefs, R.E.; “Sibling competition, hatching asynchrony, incubation period, and lifespan in altricial birds”; in Power, Dennis M. (editor); Current Ornithology. Vol. 11. This combination, normally impossible due to intense competition for food,Losdat, Sylvain, Helfenstein, Fabrice, Gaude, Benoît and Richner, Heinz; occurs because parents and (usually) helpers can organise food supply in such a manner that sibling competition for food is virtually absent.Ricklefs, Robert E.; “SIBLING COMPETITION AND THE EVOLUTION OF BROOD SIZE AND DEVELOPMENT RATE IN BIRDS”
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 .
Species The genus contains 14 species: Image Common name Scientific name Distribution Mountain thornbill Acanthiza katherina north-east Queensland, Australia Brown thornbill Acanthiza pusillasouth-eastern Australia, Tasmania Inland thornbill Acanthiza apicalisAustralia, New Guinea Tasmanian thornbill Acanthiza ewingiiTasmania and the Bass Strait Islands. New Guinea thornbill Acanthiza murina New Guinea Chestnut-rumped thornbill Acanthiza uropygialisAustralia. Buff-rumped thornbill Acanthiza reguloidesEastern Australia. Western thornbill Acanthiza inornatasouthwestern Australia. Slender-billed thornbill Acanthiza iredaleiAustralia. Yellow-rumped thornbill Acanthiza chrysorrhoasouthern and eastern Australia as well as Tasmania Yellow thornbill Acanthiza nanaeastern coast of Australia. Grey thornbill Acanthiza cinerea New Guinea Striated thornbill Acanthiza lineataAustralia Slaty-backed thornbill Acanthiza robustirostrisAustralia.
References
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.
External links
Acanthiza fotos & videos on the Internet Bird Collection