Psophodes

''Psophodes'' is a genus of five species of songbirds endemic to Australia, known as whipbirds and wedgebills.

Description

Whipbirds and wedgebills are collectively recognised in the genus ''Psophodes''.Toon, A., Joseph, L., & Burbidge, A., (2013). Genetic analysis of the Australian whipbirds and wedgebills illuminates the evolution of their plumage and vocal diversity. ''Emu''. Vol. 113, pp. 359-366. Wedgebills are divided into the chirruping wedgebill (''Psophodes cristatus'') and the chiming wedgebill (''Psophodes occidentalis''). Whipbirds are divided into the eastern whipbird (''Psophodes olivaceus'') and the western whipbird (''Psophodes nigrogularis''). Subspecies of the western whipbird residing in Western Australia are known to be endangered.
Barrett, R., (2013). Ecological importance of sedges: A survey of the Australasian Cyperaceae genus ''Lepidosperma''. ''Annals of Botany''. Vol. 111, pp. 499-529.

''Psophodes'' are shy, medium-sized, insectivorous birds that live in the undergrowth.Watson, M., (1969). Significance of antiphonal song in the eastern whipbird, ''Psophodes olivaceus''. ''Behaviour''. Vol. 35, pp. 157-178. Characteristics of ''Psophodes'' include the presence of a crest and a heavy, laterally compressed bill. They have a long tail with strongly developed legs and feet as well as short rounded wings.Ford, J., (1970). Distribution, ecology and taxonomy of some western Australian passerine birds. ''Emu''. Vol. 71, pp. 103-120. Wedgebills have their sixth and seventh primary feathers as well as the bends in the edges of the wings in white. The edgebill has eight restrices on the outside tipped with white, while the whipbird has only six white tips. Their movements in walking, bowing, and postures are almost identical between whipbirds and wedgebills.

The chirruping wedgebill and the chiming wedgebill are plain grey-brown in appearance with small crests. The two wedgebills are nearly undecipherable except for their vocalisations and song. In contrast, the whipbirds (eastern and western) whilst sharing many similarities with the wedgebills, are evidently different, especially in plumage. The majority are olive-green with white malar patches, as well as black throats or upper chests. The vocalisations of the western whipbird are very similar to the wedgebills, however, the eastern whipbird differs once again in vocalisation. The eastern whipbird's plumage is similar to that of the western whipbird, however, they have a far more conspicuous white malar patches and are a richer olive-green colour.

Distribution/population

''Psophodes'' are found in many areas of Australia. The chirruping wedgebill is located on the plains of central Australia, mainly among the Lachlan and Darling, however, they have been found on the lower Naomi.McAllan, I., & O’Brien, R., (2006). Early records of the chirruping wedgebill ''Psophodes cristatus'' from New South Wales and Victoria. ''Australian field ornithology''. Vol. 23, pp. 20-28. Currently, the chirruping wedgebill is found as far east as the Darling River near Louth (30°35’S, 145°05’E), Coronga Peak (30°45’S, 146°19’E), and Cobar (31°30’S, 145°50’E). There have been records of the chirruping wedgebill in Victoria near the southwestern border with New South Wales.

The eastern whipbird distribution is from the eastern side of Australia from northeastern Queensland to eastern New South Wales and Victoria.Mennill, D., & Rogers, A., (2006). Whip it good! Geographic consistency in male songs and variability in female songs of the duetting eastern whipbird ''Psophodes olivaceus''. ''Journal of avian biology''. Vol. 37, pp. 93-100. The western whipbird is found in coastal areas from Perth to Hopetoun and in mallee heath between Wongan Hills and Hopetoun.Smith, G., (1991). Ecology of the western whipbird ''Psophodes nigrogularis'' in western Australia. ''Emu''. Vol. 91, pp. 145-157. The bird also covers areas within the southwest of Australia and west of the sclerophyll forest. Records indicate the western whipbird is also found in Mt Gardner, Two People Bay, Mallee country, Banksia, stunted heath around Gnowangerup, and Borden.

Taxonomy

Members within the genus ''Psophodes'' are closely related to the quail thrushes within the Corvida family Cinclosomatidae.Rogers, A., & Mulder, R., (2004). Breeding ecology and social behaviour of an antiphonal duetter, the eastern whipbird (''Psophodes olivaceus''). ''Australian Journal of Zoology''. Vol. 52, pp. 417-435. The eastern whipbird is known to be one of four species of ''Psophodes''. Rogers and Mulder (2004) also suggest two subspecies of the eastern whipbird, the southern ''P. livaceus'' and the northern ''P. lateralis''. These two subspecies have been identified based on their geographic location within Australia as well as their morphology and plumage.

Two subspecies of the black-throated whipbird include: ''Psophodes nigrogularis oberon'' and ''Psophodes nigrogularis nigrogularis''.

The wedgebills have their own place in ''Psophodes''. Ford and Parker (1972)Ford, J., & Parker, S., (1972). A second species of wedgebill? ''Emu''. Vol. 73, pp. 113-118. note that the wedgebill consists of two species: the eastern and the western. The current species is known as ''Psophodes cristatus'', however, the differences between the eastern and the western wedgebill are quite substantial. While morphologically similar, the contrast in their behaviour and vocalisations are quite large.

Phylogenetic research has found that the two whipbirds are not sister taxa. Toon, Joseph, and Burbidge's (2013) study found that the eastern whipbird shares a more recent ancestor with wedgebills than the western whipbird. The inclusion of the Papuan whipbirds (''Androphobus'') in the genus may see the western whipbird become the sister species to that group. Schodde and Mason (1999) recognised that there could be three lineages within ''Psophodes''; the eastern whipbird, western whipbird and the wedgebills. This however, has not yet been confirmed.

Further conjecture has occurred through other DNA sequencing studies of birds. A recent study has found that the Psophodidae (whipbirds and quail thrushes) was polyphyletic, with Cinclosomatidae (quail thrushes) and Ptilorrhoa (jewel-babblers) comprising a lineage unrelated to ''Psophodes'' (whipbirds and wedgebills). This too has yet to be confirmed.Norman, J., Ericson, P., Jonsson, K., Fjeldsa, J., & Christidis, L., (2009). A multi-gene phylogeny reveals novel relationships for aberrant genera of Austro-Papuan core corvoidea and polyphyly of the pachycephalidae and Psophodidae (aves: Passeriformes). ''Molecular Phylogenetics and Evolution''. Vol. 52, pp. 488-497.

Species

Habitat/ecology

The black-throated whipbird is found in coastal thickets and dense forest understorey vegetation. Their preferred habitat consists of two-layered formation 2–3 metres high with understoreys which are dense to mid-dense. The black-throated whipbird is known as the ‘rain bird’ as it is seeks the summit of coastal areas preceding rain. The bird is difficult to find as it is a ground runner and it rarely leaves low shrub areas.Howe, F., & Ross, J., (1933). On the occurrence of ''Psophodes nigrogularis'' in Victoria. ''Emu''. Vol. 32, pp. 133-148. It is observed that the eastern whipbird prefers tall moist forest and riparian areas,Martin, T., & Possingham, H., 2005. Predicting the impact of livestock grazing on birds using foraging height data. ''Journal of applied ecology''. Vol. 42, pp. 400-408. even though the upper layer is rarely used.

Common amongst all species of ''Psophodes'', the surrounding flora has a ground layer of approximately 5 cm deep mainly made from sclerophyllous leaves. Between the species of ''Psophodes'', there is a theme of preferences of structure over floristics