Acanthiza is a genus of passeriform birds, mostly found in Australia but with one species (A. murina) restricted to New Guinea. These birds are commonly known as thornbills. They are not closely related to species in the hummingbird genus Chalcostigma which are also called thornbills. The habitat preferences of the group vary from dense forest to open saltbush and bluebush plains. 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).