The white-winged fairywren (Malurus leucopterus) is a species of passerine bird in the Australasian wren family, Maluridae.

Like other fairywrens, this species displays marked sexual dimorphism and one or more males of a social group grow brightly coloured plumage during the breeding season.

The female is sandy-brown with light-blue tail feathers; it is smaller than the male, which, in breeding plumage, has a bright-blue body, black bill, and white wings.

Like other fairywrens, it is a cooperative breeding species, and small groups of birds maintain and defend territories year-round.

A specimen of the white-winged fairywren was first collected by French naturalists Jean René Constant Quoy and Joseph Paul Gaimard in September 1818, on Louis de Freycinet's voyage around the Southern Hemisphere.

The specimen was subsequently lost in a shipwreck, but a painting entitled Mérion leucoptère by Jacques Arago survived and led to the bird's description in 1824 by French ornithologist Charles Dumont de Sainte-Croix.

[5] George Mack, ornithologist of the National Museum of Victoria, considered the specific name leuconotus to take precedence in his 1934 revision of the genus,[6] and more recent studies have followed suit.

[15] Termed the bicoloured wrens by ornithologist Richard Schodde, these three species are notable for their lack of head patterns and ear tufts and their uniform black or blue plumage with contrasting shoulder or wing colour; they replace each other geographically across northern Australia and New Guinea.

Gene flow between the populations existed at the beginning of the present interglacial period, some 8,000 to 10,000 years ago, at a time when sea levels were lower and both islands connected with the mainland.

[22] The distribution of the three bi-coloured fairywren species indicates their ancestors lived across New Guinea and northern Australia in a period when sea levels were lower and the two regions were joined by a land bridge.

[25] Wider than it is deep, the bill is similar in shape to those of other birds that feed by probing for or picking insects off their environs.

In contrast, during the breeding season, fertile females develop oedematous brood patches, which are bare areas on their bellies.

[24] Males entering their second or third year may develop spotty blue and white plumage during the breeding season.

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

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

[31] In 1980, Tideman characterised five different patterns of calls among Malurus leucopterus leuconotus; these were recognised by Pruett and Jones among the island subspecies M. l. edouardi.

[41] Several subgroups live within one territory and make up a clan, which is presided over by one blue (or black) male who assumes breeding plumage.

[24] Additionally, the feeding territories are larger during the winter months when these birds spend much of their time foraging with the entire clan.

The fairywren lowers its head and tail, outstretches and quivers its wings and holds its beak open silently.

[27] Both the male and female adult white-winged fairywren may utilise a rodent-run display to distract predators from nests with young birds.

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.

[42] Fairywrens exhibit one of the highest incidences of extra-pair mating, and many broods are brought up a by male who is not the natural father.

[42] During another courtship display the male bows deeply forward facing the female, reaching the ground with his bill and spreading and flattening his plumage in a near-horizontal plane for up to 20 seconds.

[44] Breeding females begin to build their nests in the spring and construct domed structures composed of spider webs, fine grasses, thistle-down, and vegetable-down, typically 6 to 14 centimetres (2.4 to 5.5 in) tall and 3 to 9 millimetres (0.12 to 0.35 in) thick.

The newly hatched nestlings are altricial, gaping immediately for food, and developing downy feather tracts and opening their eyes by the third or fourth day.

[47] The white-winged fairywren is primarily insectivorous; its diet includes small beetles, bugs, moths, praying mantises, caterpillars, and smaller insects, as well as spiders.

Adults and juveniles forage by hopping along the shrubland floor, and may supplement their diets with seeds and fruits of saltbush (Rhagodia), goosefoot (Chenopodium) and new shoots of samphire.