These birds are primarily insectivorous and forage and live in the shelter of scrubby vegetation east of the Great Dividing Range.

[8] More recently, DNA analysis has shown the family to be related to the honeyeaters (Meliphagidae) and the pardalotes (Pardalotidae) in a large superfamily Meliphagoidea.

[12] In his 1982 monograph, ornithologist Richard Schodde proposed a northern origin for the chestnut-shouldered fairywren group due to the variety of forms in north and their absence in the southeast of the continent.

Ancestral birds spread south and colonised the southwest during a warm wetter period around 2 million years ago at the end of the Pliocene or beginning of the Pleistocene.

Further warmer, humid conditions again allowed birds to spread southwards, this group occupying central southern Australia east to the Eyre Peninsula became the blue-breasted fairywren.

Finally, after the end of the last glacial period 12,000–13,000 years ago, the northern variegated forms have again spread southwards, resulting in the purple-backed fairywren.

[13] A 2017 molecular analysis by Alison J. McLean and colleagues of the former subspecies of the variegated fairywren largely supported Schodde's hypothesis.

[14] In 2018, this split was recognized by the International Ornithological Committee with the subspecies to the north and west reallocated to the purple-backed fairywren.

[17] Like other fairywrens, it is notable for its marked sexual dimorphism, males adopting a highly visible breeding plumage of brilliant iridescent blue and chestnut contrasting with black and grey-brown.

[21] The blue coloured plumage, particularly the ear-coverts, of the breeding males is highly iridescent due to the flattened and twisted surface of the barbules.

[21] The blue plumage also reflects ultraviolet light strongly, and so may be even more prominent to other fairywrens, whose colour vision extends into that part of the spectrum.

Movement is a series of jaunty hops and bounces,[30] its balance assisted by a relatively large tail, which is usually held upright, and rarely still.

[25] Breeding occurs from spring through to late summer; the nest is generally situated in thick vegetation and less than 1 m (3.3 ft) above the ground.

[37] The variegated fairywren consumes a wide range of small creatures, mostly insects, including ants, grasshoppers, bugs, flies, weevils and various larvae.

[35] Major nest predators include Australian magpies, butcherbirds, laughing kookaburra, currawongs, crows and ravens, and shrike-thrushes, as well as introduced mammals such as the red fox, feral cats and black rat.

The head, neck and tail are lowered, the wings are held out and the feathers are fluffed as the bird runs rapidly and voices a continuous alarm call.