The white-winged fairywren (Malurus leucopterus) is a species of passerine bird in the Australasian wren family, Maluridae. It lives in the drier parts of Central Australia; from central Queensland and South Australia across to Western Australia. 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. Younger sexually mature males are almost indistinguishable from females and are often the breeding males. In spring and summer, a troop of white-winged fairywrens has a brightly coloured older male accompanied by small, inconspicuous brown birds, many of which are also male. Three subspecies are recognised. Apart from the mainland subspecies, one is found on Dirk Hartog Island, and another on Barrow Island off the coast of Western Australia. Males from these islands have black rather than blue breeding plumage.
The white-winged fairywren mainly eats insects, supplementing this with small fruits and leaf buds. It occurs in heathland and arid scrubland, where low shrubs provide cover. Like other fairywrens, it is a cooperative breeding species, and small groups of birds maintain and defend territories year-round. Groups consist of a socially monogamous pair with several helper birds who assist in raising the young. These helpers are progeny that have attained sexual maturity but remain with the family group for one or more years after fledging. Although not yet confirmed genetically, the white-winged fairywren may be promiscuous and assist in raising the young from other pairings. As part of a courtship display, the male wren plucks petals from flowers and displays them to female birds.
Taxonomy and systematics
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.Schodde (1982), p. 108 The name for the species was derived from the Ancient Greek leuko- "white" and pteron "wing".
Ironically, the original specimen was of the black-plumaged subspecies from Dirk Hartog Island, which was not recorded again for 80 years. Meanwhile, the widespread blue-plumaged subspecies was discovered and described as two separate species by John Gould in 1865. He called one specimen collected from inland New South Wales the white-winged superb warbler (M. cyanotus), while another, which appeared to have a white back and wings, was described as the white-backed superb warbler (M. leuconotus). It was not until the early 20th century that both of these blue-plumaged mainland forms were found to be of a single species.Rowley & Russell (1997), p. 177 George Mack, ornithologist of the National Museum of Victoria, considered the specific name leuconotus to take precedence in his 1934 revision of the genus, and more recent studies have followed suit.Rowley & Russell (1997), p. 178 The back region between the shoulders is in fact bare, with feathers that arise from the shoulder (scapular) region and sweep inwards in different patterns. This variation confused the early naturalists who described the white-backed and blue-backed species.
The white-winged fairywren was often referred to as the blue-and-white wren, and early observers, such as Norman Favaloro of Victoria, refer to them by this name. However, like other fairywrens, the white-winged fairywren is unrelated to the true wren (family Troglodytidae). Other alternative names used include the white-backed fairywren, white-backed wren and white-winged wren. It was previously classified as a member of the Old World flycatcher family, Muscicapidae, and later as a member of the warbler family, Sylviidae, before they were placed in the newly recognised Australasian wren family, Maluridae, in 1975. More recently, DNA analysis has shown the family Maluridae to be related to the family Meliphagidae (honeyeaters), and the Pardalotidae (pardalotes, scrubwrens, thornbills, gerygones and allies) in the large superfamily Meliphagoidea.
The white-winged fairywren is one of eleven species in the genus Malurus. It is most closely related to the Australian red-backed fairywren, with which it makes up a phylogenetic clade with the white-shouldered fairywren of New Guinea as the next closest relative. 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.Schodde (1982), p. 31
Subspecies There are three recognised subspecies. Both black-plumaged forms have been called the black-and-white fairywren and black-and-white wren.
M. l. leucopterus - Dumont, 1824 Range of the nominate subspecies is restricted to Dirk Hartog Island, off the western coast of Australia, and nuptial males display black-and-white plumage. This subspecies is the smallest of the three and bears a proportionally longer tail.Rowley & Russell (1997), pp. 177–178 It was collected again in 1916 by Tom Carter, 98 years after de Freycinet's expedition collected the type specimen. M. l. edouardi - Campbell, A.J, 1901: Originally described as a separate species, this subspecies, like the nominate subspecies, have black-and-white coloured males, but are found only on Barrow Island, also off the western coast of Australia. Birds of this subspecies are larger than those of the nominate subspecies but have a shorter tail. The female has a more cinnamon tinge to her plumage than the grey-brown of the other two subspecies. Blue-and-white fairywren (M. l. leuconotus) - Gould, 1865: Originally described as a separate species, it is endemic to mainland Australia and distinct in that it is the only subspecies to have nuptial males that show prominent blue-and-white plumage. The scientific name of this subspecies is derived from the Ancient Greek leukos 'white' and notos 'back'. Birds in the southern parts of its range tend to be smaller than those in the north.
M. l. leucopterus and M. l. edouardi are both generally smaller than their mainland relatives, and both subspecies tend to have smaller family groups that consist of only one male and one female, with an occasional helper bird. While the island subspecies and mainland species have been found to have similar social structure, breeding pairs on both islands have, on average, smaller clutches, longer incubation times, and fewer live fledglings. Additionally, while M. l. leuconotus is considered of least concern by the IUCN due to its widespread occurrence, both island subspecies are considered vulnerable by the Australian government due to their delicate nesting sites that are easily disturbed by human construction and habitation.
Evolutionary history Both island subspecies are nearer in genetic distance to mainland populations of leuconotus than to each other; Dirk Hartog Island is from the mainland while Barrow Island is from the mainland. 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.
There are three theories as to how the three races of white-winged fairywren could have evolved. The first suggests that black-and-white plumage is an ancestral condition and, following separation of the three populations, blue-and-white plumage evolved in the mainland species. The second hypothesis suggests that black-and-white plumage evolved convergently on the two separate islands. The third suggests that black-and-white plumage evolved once from the blue-and-white ancestral condition, and later the mainland species re-evolved blue plumage.
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. Populations became separated as sea levels rose, and New Guinea birds evolved into the white-shouldered fairywren, and Australian forms into the red-backed fairywren and the arid-adapted white-winged fairywren.Rowley & Russell (1997), p. 31
Description
Measuring in length, white-winged fairywrens are one of the two smallest species of Malurus. Males typically weigh between while females weigh between . Averaging in males and in females, the bill is relatively long, narrow and pointed and wider at the base.Rowley & Russell (1997), p. 38 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. It is finer and more pointed in this species than in other fairywrens.
Fully mature adults are sexually dimorphic, with the male being larger and differing in colour from the female. The adult female is sandy-brown with a very light blue tail, and a pinkish buff bill. The male in breeding plumage has a black bill, white wings and shoulders, and a wholly cobalt blue or black body (depending on subspecies). These contrasting white feathers are especially highlighted in flight and ground displays in breeding season. The male in eclipse plumage resembles the female, though it may be distinguished by its darker bill.Rowley & Russell (1997), p. 176 Both sexes have long, slender, distinct tails held at an upward angle from their bodies. Measuring around , the tail feathers have a white fringe, which disappears with wear.Rowley & Russell (1997), p. 37
Nestlings, fledglings, and juveniles have brown plumage and pink-brown bills with shorter tails than adults. Young males develop blue tail feathers and darker bills by late summer or autumn (following a spring or summer breeding season), while young females develop light blue tails. By the subsequent spring, all males are fertile and have developed cloacal protuberances, which store sperm. In contrast, during the breeding season, fertile females develop oedematous brood patches, which are bare areas on their bellies. Males entering their second or third year may develop spotty blue and white plumage during the breeding season. By their fourth year, males have assumed their nuptial plumage, where the scapulars, secondary wing coverts, and secondary flight feathers are white while the rest of their bodies are a vibrant cobalt blue. All sexually mature males moult twice a year, once before the breeding season in winter or spring, and again afterwards in autumn; rarely, a male may moult directly from nuptial to nuptial plumage. The breeding males' blue plumage, particularly the ear-coverts, is highly iridescent due to the flattened and twisted surface of the barbules.Rowley & Russell (1997), p. 44 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.
Vocalisations