Unlike the related superb fairywren, it has not adapted to urbanised habitats very well and has suffered severe population loss in some areas.

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

[15] These evolutionary radiations followed an earlier split of the grasswrens Amytornithinae from what would become the emu-wrens and fairy wrens approximately 23 million years ago.

It can be differentiated from other North Australian fairywrens by the presence of cheeks patches and the deep blue color of their tails.

Immature birds are very similar to adult females except for a duller coloration, a brown crown, and longer tail, though male birds start to show black feathers on the face by six to nine months [19] Within a group, males who are breeding molt into their bright crown earlier than their non-breeding subordinates, and do so even sooner after heavy rains the preceding season.

[18][6] Whilst the species’ distribution spans more than 1,500 km (930 mi), it is constrained by the quality and extent of riparian vegetation along waterways.

[18] The purple-crowned fairywren is a riparian habitat specialist that occurs in patches of dense river-fringing vegetation in northern Australia.

[28] Like all other species in the genus Malurus, the purple-crowned fairywren is a cooperative breeder and lives in sedentary groups that maintain their territories, often arranged linearly along creeks and rivers, year-round.

[19] The spatial arrangement of purple-crowned fairywren territories differ depending on what plant species dominate the understory.

[31] Breeding can occur at any time throughout the year, if conditions are suitable, with peaks in the early (March to May) and late (August to November) dry season.

[19] Only the females build the small dome shaped nests constructed mainly of fine rootlets, grass, leaves and strips of bark.

[19] Incestuous matings by the purple-crowned fairywren result in severe fitness costs due to inbreeding depression (greater than 30% reduction in hatchability of eggs).

[19][25] Group members will forage separately, hopping rapidly through the dense undergrowth, but remain in contact with each other by making soft chet sounding calls.

[40] Numerous native animals potentially prey on eggs and nestlings of the purple-crowned fairywren, such as small semi-aquatic monitors (Varanus mitchelli, and V. mertensi), yellow-spotted goanna, Gilbert's dragon, common tree snake, common brown tree snake, olive python and pheasant coucals.

The purple-crowned fairywren's greatest threat is degradation or loss of habitat from introduced herbivores, weeds, fire, flooding and mining.

[38] Introduced herbivores seeking water eat and trample riparian vegetation that purple-crowned fairywrens rely on for foraging, nesting and shelter.

[28] Populations of M. c. coronatus decreased by 50% over a two-year period at two sites in the Victoria River District where grazing and trampling was allowed around habitat patches.

The species disappeared from the lower Fitzroy River around the 1920s with the introduction of sheep and cattle grazing, and subsequent replacement of native riparian vegetation by weeds.

Small populations on the northern Pentecost and Isdell Rivers are at the highest risk of extirpation, and urgently need a fine-scale targeted approach to help conserve them.

[42] A strategy that maintains connectivity across the species distribution and reduces continuing riparian degradation needs to be implemented.

[42] The Department of Agriculture and Food Western Australia (DAFWA) joined with Wungurr Rangers and pastoralists in the north-west Kimberley in an effort to protect parts of their habitat by removing Ornamental rubbervine (Cryptostegia madagascariensis).

The Australian Wildlife Conservancy (AWC) is protecting riparian vegetation on its Mornington-Marion Downs, and Pungalina-Seven Emu sanctuaries by implementing a program of fire management (EcoFire) and introducing herbivore control.

EcoFire is a landscape-scale fire management program of the central and north Kimberley (involving 11 properties covering four million hectares including indigenous communities and pastoralists), and helps protect the fire-sensitive vegetation crucial for the survival of the purple-crowned fairywren.