Weebill

Species of bird

The weebill (Smicrornis brevirostris) is a species of bird in the family Acanthizidae. It is an insectivorous passerine that is found throughout mainland Australia. At long, it is Australia's smallest bird. It was originally described by John Gould in 1838, and four subspecies are recognised. The weebill's plumage is nondescript, with olive grey upperparts and paler, more yellowish underparts. It grades from more brownish plumage in the southern regions of Australia to more yellow in tropical areas.

The weebill was described by John Gould in 1838 as Psilopus brevirostris. The species epithet is derived from the Latin words brevis 'short' and rostrum 'beak'. In 1843, Gould erected the genus Smicrornis for his new species Smicrornis flavescens, collected from Port Essington, noting it as distinct from Gerygone (which had replaced Psilopus as a name). The generic name Smicrornis derives from the Greek smicros 'small' and ornis 'bird'. It is the only member of genus Smicrornis; gene flow is strong and local variation follows Bergmann's and Gloger's rules. Gould initially called it the short billed smicrornis, but it did not gain acceptance. Other names include tree tit, short billed tree tit, scrub tit, or short billed scrub tit. Weebill was adopted as the name in the 1926 RAOU checklist. Wingspan is approximately The legs and feet of the weebill are grey, and like all passerines, their toe arrangement is anisodactyl for perching. Additionally, the Northern Australian weebills are smaller than those in the south. The voice of the weebill is a loud, clear, musical pee pee p'wee, wee bit or wee willy weetee, often heard from a considerable distance. All four subspecies of weebills are sedentary in their range, The weebill is widespread in all climates, although localised to watercourses in arid zones. They are somewhat gregarious with other small insectivorous passerines, such as thornbills, silvereyes, and pardalotes.

The diet consists mostly of insects, larvae, occasionally seeds and beetles Weebills forage busily in pairs, or small parties of up to 8, feeding mainly in trees, often hovering, they are active and noisy and cling to twigs while gleaning insects from the outer foliage of the canopy and midstory. Weebills assist in maintaining the health of trees, as they glean scale insects and eat a range of other insects, including psyllids and their protective covers (lerps). Weebills are known to utilize cobwebs, insect cocoons and animal hair to bind, strengthen, and further conceal the nest. The breeding season of weebills depends on latitude and climatic conditions. Weebill eggs in the nest are occasionally vulnerable to small brood parasites, such as the Horsfield's bronze cuckoo, where the female cuckoo removes the weebill eggs and lays one or two eggs in the host nest for the weebill to raise.

Widespread and common in its habitat throughout its range on mainland Australia, the weebill is evaluated as Least Concern on the IUCN Red List of Threatened Species. and other anthropogenic changes to the characteristics of the land. Human caused disturbances include introduced flora and fauna species, and altered fire regimes that can result in changes to ecosystem level processes, modify habitat structure and consequently affect fauna assemblages.