Mallee whipbird

The Mallee whipbird is a member of the family Psophididae. The taxonomic history of the Mallee whipbird is complicated and has at times been controversial.^[3] It was previously treated as a subspecies of the Western whipbird;^[4] however, based on more recent morphological and mitochondrial DNA analysis, it is currently accepted as a subspecies of the white-bellied whipbird and a sister taxon to the Kangaroo Island whipbird.^[5][6][7]

The Mallee whipbird is endemic to coastal and inland areas of mainland southern South Australia (SA) and north-western Victoria (Vic). The subspecies is thought to consist of four highly disjunct subpopulations^[8] centred on:

1. southern Yorke Peninsula (SA);
2. southern Eyre Peninsula (SA);
3. Billiatt Conservation Park in the eastern Murray Mallee region of SA; and
4. Ngarkat Conservation Park in the eastern Murray Mallee region of SA and Big Desert Wilderness Park in north-western Vic.

These subpopulations are largely confined to protected areas; however, it is estimated that there is enough suitable habitat on private land on the Yorke and Eyre Peninsulas to facilitate sufficient dispersal to be considered a single continuous subpopulation.^[9]

The two eastern-most subpopulations are estimated to be very small^[10] and the subspecies was previously thought to be locally extinct in Ngarkat Conservation Park and north-western Victoria until surveys in late 2022 confirmed the presence of the subspecies.^[10][11] Whilst known to historically occur in Billiatt Conservation Park, the surveys undertaken in 2022 did not detect any individuals and this subpopulation is not thought to be locally extinct.^[10]

The Mallee whipbird is a medium-sized bird that is 20–25 cm in length with a wing span of 24–26.5 cm and a mass of approximately 43 - 47 g.^[12] It has a short, grey-brown, triangular erectile crest on the forehead that is often raised in alarm.^[2] The bill in adults is grey-brown, stout and slightly decurved, measuring 13–14 mm in length.^[13] Nestings and juveniles have a darkish-grey bill with a pale yellow cutting-edge (tomium).^[2] The legs are long, slender and dark-grey in colour^[2] and the wings are short and elliptical^[2] allowing for short bursts of high speed and manoeuvring through dense vegetation when seeking cover. Upper- and lowerparts are mostly dull olive to olive-grey and greyish-brown blending into a prominent white submoustachial stripe on each cheek, a broad white stripe down the breast and belly and a black chin and throat.^[12] The tail is long, graduated and fan-shaped when spread, with a rounded tip and rectrices that have a black subterminal band and white tips.^[2] The eye is dull red with a narrow grey eye-ring.^[8]

Juveniles are uniformly olive-grey-brown and are separable from adults in that they lack the black and white colouring on the cheeks, chin and throat and have a rudimentary crest.^[12] Immatures are thought to closely resemble adults within 3 months of fledging but retain juvenile remiges, coverts and rectrices.^[13]

The Mallee whipbird does not display sexual dimorphism nor seasonal variation in plumage.^[13]