The buff-rumped thornbill (''Acanthiza reguloides'') is a small passerine bird species belonging to the genus ''

Acanthiza ''Acanthiza'' is a genus of perching bird, 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 relat ...

'', most of which are endemic to Australia. Measuring 8–10 cm in length, this unassuming thornbill is characterised by its plain greenish brown upperparts and very pale-yellow underparts, with a distinctive buff coloured rump. The tail has a broad, blackish band with a paler tip. Adults possess white irises, whilst juveniles have dark eyes. The buff-rumped thornbill is one of 14 species within the genus ''

'' genus, which are recognisable by their thin, pointed bill. Species are unique in their plumage and distribution. Despite their shared name, the genus is not related to hummingbirds.

Taxonomy

Early classifications of the genus ''Acanthiza'' based on plumage and morphology recognised one to three genera with a varying number of species in each. However, recent classifications have recognised one genus containing five species groups or four groups excluding the New Guinean ''murina''. The taxonomy of the ''Acanthiza reguloides'' has undergone significant change and debate since its early classification. Despite marked differences between ''A. reguloides'' and ''A. squamata'', they have been combined as a single species since 1926. Four subspecies of Acanthiza reguloides are recognised. These are: *''Acanthiza reguloides'' subsp. ''australis'' *''Acanthiza reguloides'' subsp. ''nesa'' *''Acanthiza reguloides'' subsp. ''reguloides'' *''Acanthiza reguloides'' subsp. ''squamata''

Distribution and habitat

Primarily distributed in eastern Australia, the buff-rumped thornbill's range spans from

Chinchilla Chinchilla refers to either of two species ('' Chinchilla chinchilla'' and '' Chinchilla lanigera'') of crepuscular rodents of the parvorder Caviomorpha, and are native to the Andes mountains in South America. They live in colonies called "her ...

, Queensland, west to

Cobar Cobar is a town in Outback New South Wales, Australia, whose economy is based mainly upon base metals and gold mining. The town is by road northwest of the state capital, Sydney. It is at the crossroads of the Kidman Way and Barrier Highwa ...

, New South Wales, across Victoria and southeastern South Australia. This is an area of approximately 2 000 000 km2. This adaptable species thrives in dry sclerophyll forests and open eucalypt woodlands that have an open or sparse understorey. Distribution of the Buff Rumped Thornbill in Australia

Distribution of the Buff Rumped Thornbill in Australia

Diet

The thornbill's diet consists primarily of small insects and plant lice gleaned from foliage. It occasionally eats seeds.

Reproduction

''A. reguloides'' builds a large, dome shaped nest consisting of bark strips, dried grass and moss located one to two metres above the ground. It is lined with fur, plant or down and bound with spider web on the outside. Thornbills work together cooperatively in groups consisting of usually one female and three males. Females typically lay clutches of 2-4 eggs in late August with an incubation period of 20 days. Egg hatching is highly synchronous and adults of the

cooperative breeding Cooperative breeding is a social system characterized by alloparental care: offspring receive care not only from their parents, but also from additional group members, often called helpers. Cooperative breeding encompasses a wide variety of group s ...

group work together to feed the chicks. Adults grow to 8–10 cm in length. Horsfield's bronze-cuckoo ('' Chalcites basalis'') is known to lay eggs in the nest of ''A. reguloides''. Cuckoo nestlings learn to mimic the vocalisations of ''A. reguloides'' before evicting them from the nest.

Behaviour

Buff-rumped thornbills are often found in small, chatty groups of approximately 20 individuals, but may join during non-breeding season to form larger clans. They continuously twitter as they forage. Their vocalizations are characterized by a rapid pitta-pitta-pitta-pit call. They have a hearing range of 5000 Hz and a hearing threshold of 10 dB. In flight, ''Acanthiza'' spp. exhibit a characteristic undulating path. These birds are exceptional acrobats, displaying a remarkable ability to remain head downward. Birds are known to be territorial.

Conservation status

Bird populations are known to be secure in all states of Australia in which they are present. However, urban development and habitat modification has caused a decline in numbers in some areas.

References

{{Taxonbar, from=Q1301064 buff-rumped thornbill Birds of Queensland Birds of New South Wales Birds of Victoria (state) Endemic birds of Australia buff-rumped thornbill Articles containing video clips