The Mountain Thornbill (Acanthiza katherina) is a small, insectivorous bird that is endemic to Australia. It belongs to the family Acanthizidae which includes nearly all the Australian warblers.
Mountain Thornbills live in the alpine and subalpine regions of southeastern Australia, where they are often seen flitting through the shrubs and trees. The bird is about 4-5 cm long and weighs around 6-8 grams. They have a small, stubby bill and are characterized by their striking yellow-orange crown and dark wings. The upperparts are dark grey-brown, and the underparts are pale grey, with a reddish-brown patch on their lower belly.
The Mountain Thornbill is a highly active bird, constantly flitting about the branches and bark in search of insects and larvae, which make up their primary diet. They are a territorial bird, defending their small area fiercely against intruders, and can be seen rapidly chasing off other birds who stray into their territory. They also have a habit of hovering in mid-air while foraging, giving them an almost hummingbird-like appearance.
Like most species of Australian birds, the Mountain Thornbill is monogamous and pairs form lifelong bonds. The female lays around three to five eggs in a cup-shaped nest made of bark, which is constructed in a shrubby or tree-lined area. The male and female share the responsibility of incubating the eggs.
The Mountain Thornbill is considered a species of least concern from a conservation standpoint, with healthy populations throughout its range. Its habitat has been impacted by human activities such as land clearing and habitat fragmentation caused by the introduction of feral animals like deer and rabbits. The possibility of climate change also poses a potential threat to its alpine habitat.
Overall, the Mountain Thornbill is a charming and fascinating bird of the Australian high-country. Its distinctive appearance and behavior have made it a favorite among bird watchers and photographers and are certainly a unique addition to Australia's rich and diverse birdlife.