Large-billed Scrubwrens are sometimes labelled with the doubtful distinction of being the plainest bird in Australia. Devoid of any distinctive markings, their most obvious field character is their upturned bill which really looks as though it was stuck on the head at the wrong angle. Clearly an adaption to a particular mode of feeding, no obviously different behaviour has ever been described, although they have been observed to feed under bark, "spiralling up vines and trunks of trees" and "gleaning arthropods from bark of narrow woody stems of tall shrubs or small trees, vines and pendulous ribbons of bark". In this respect, they share with the Sittellas an upturned bill - they also both feed a lot under bark.

Large-billed Scrubwrens are restricted to the coastal rainforests of eastern Australia from Cooktown to near Melbourne. Adults do appear to live in permanent territories and nest as pairs although some records of more than two birds attending a nest may refer to a sociable habit. Certainly, Large-billed Scrubwrens are often seen feeding in groups of up to a dozen or so but what their relationships are is not known but it seems likely that these groups are comprised of an adult pair plus their progeny of the season. They rarely feed on the ground, but in the shrubby understorey of the rainforest up to about 10 metres high. The pictures 494201 and 494202 show birds attending their own nest at Tooloom in NSW, but more often than not, they usurp the old (or even new!) nest of a Yellow-throated Scrubwren.