Maluridae – Australasian Wrens

The Maluridae is a family of small, insectivorous passerines endemic to Australia and New Guinea. Commonly known as wrens, they are unrelated to the true wrens of the Northern Hemisphere. The family includes sixteen fairywrens, three emu-wrens, and thirteen grasswrens.

As with many other Australian creatures, and perhaps more than most, the species making up this family were comprehensively misunderstood by early researchers. They were variously classified as Old-World flycatchers, Old World warblers, and Old -World babblers. In the late 1960s, morphological studies began to suggest that the Australo-Papuan fairywrens, the grasswrens, emu-wrens and two monotypic wren-like genera from New Guinea were related and, following Charles Sibley’s pioneering work on egg-white proteins in the mid-1970s, Australian researchers adopted the family name Maluridae in 1975.

Male & Female Emperor Fairywren Malurus cyanocephalus – ©Dubi Shapiro

With further morphological work and the great strides made in DNA analysis towards the end of the 20th century, their position became clear: the Maluridae are one of the many families to have emerged from the great corvid radiation in Australasia. Their closest relatives are the Meliphagidae (Honeyeaters), and the Pardalotidae (Pardalotes). Their obvious similarity to the wrens of Europe and America is not genetic, but simply the consequence of convergent evolution between more-or-less unrelated species that share the same ecological niche.

Dusky Grasswren Amytornis purnelli – ©Peter Jacobs CC BY-SA 2.0 via Wikimedia Commons

A analysis of mitochondrial and nuclear DNA found the broad-billed fairywren and Campbell’s fairywren (2011), both formerly lumped together in the genus Malurus, to lie in a clade with the two other monospecific New Guinea genera and as such, they were later re-classified as separate species within the genus Chenorhamphus.

Purple-crowned Fairywren Malurus coronatus – ©Graham Winterflood CC BY-SA 2.0 via Wikimedia Commons

They are small birds, inhabiting a wide range of environments, from rainforest to desert, although most species inhabit grassland or scrub. The grasswrens are well camouflaged with black and brown patterns, but other species often have brilliantly coloured plumage, especially in the males. They live in a wide variety of habitats in Australia and New Guinea.

The whole family are insectivorous, typically foraging in underbrush. They build domed nests in areas of dense vegetation, and it is not unusual for the young to remain in the nest and assist in raising chicks from later clutches.

Fairywrens are notable for several peculiar behavioural characteristics. They are socially monogamous and sexually promiscuous, meaning that although they form pairs between one male and one female, each partner will mate with other individuals and even assist in raising the young from such pairings. Though their plumage colours are varied, some with exquisite splashes of blue and red and others streaked in muted earth tones, this diversity is grounded in a unified body plan and some of the most complicated mating systems in birds. Indeed, males in this family have reproductive tracts that are well adapted to meet the demands of sexual competition with their rivals, and some species practice high rates of extra-pair mating. But their courtship does not just entail well-developed gonads and feathered finery; males of several species pluck petals of conspicuous colours and display them to females, a behaviour yet to be explained.

White-shouldered Fairywren Malurus alboscapulatus – ©Dubi Shapiro

The songs of fairywrens is pleasant and complex, and at least two species (superb and splendid), in addition to the alarm calls common to most small birds, have another vocalisation used when confronted by predators. This ‘Type II Vocalisation’, is song-like and used when confronted by calling butcherbirds, and sometimes other predatory birds. Its purpose is not yet understood; it is certainly not a warning call.