Family ORTHONYCHIDAE G.R. Gray, 1840

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Family ORTHONYCHIDAE G.R. Gray, 1840

Compiler and date details

R. Schodde, CSIRO Australian National Wildlife Collection, Canberra, ACT, Australia; updated and upgraded by N.W. Longmore, Museum Victoria, 2006

Orthonychidae Gray, G.R. 1840. A List of the Genera of Birds, with an indication of the typical species of each genus. London : R. & J.E. Taylor viii 80 pp. [Date published Apr 1840: published before Apr.].
Type genus:
Orthonyx Temminck, 1820.

Introduction

This family of a single genus and three species is endemic to Australia and New Guinea. In Australia, there are two species represented by three subspecies. These occur only in Queensland and New South Wales where they occupy habitats that include subtropical and tropical rainforest with the occasional extension into wet sclerophyll forests.

Logrunners are uniquely Australasian; Baird (1985) identified fossil material from Victorian localities indicating a more southern and larger earlier distributional range for the genus. Their unusual terrestrial feeding methods have been studied whereby they kick ground litter sideways to expose prey items while gleaning and probing. The birds are generally regarded as being gregarious and also found in small groups. They are locally nomadic moving around defined territories in their family groups. These groups can be very noisy. The northern Chowchilla has well-established behaviour patterns where groups collect at an arena to sing and perform to each other. These points are associated with territorial borders.

The nests are placed at ground level and are usually hidden at the base of a large buttress or other large object. The nest is an enlarged domed structure of entwined fibres and fine vines and lined with softer vegetable materials. The one or two eggs forming the clutch are pure white and unmarked.

Diagnosis

'Among Australian song-birds, logrunners are widely divergent in form and structure. Their syringes (Mayr 1931a) and fully 10-primaried and 9-secondaried wings may be conventional, and their humeral fossae single and “corvoid” (although untrabeculated), but their sterna are narrowed, dorsally attenuated and somewhat atrophied, and their palatal structure, feet, tails and colour patterns unique. Autumn-toned, the sexes are markedly dimorphic; males are duller and white-ventrumed, and females brighter and richly russet-throated and -breasted. In the bill, the ectethmoid plate is fused massively with the nasal, covering any sign of lachrymals and creating a sharply angled frontal-nasal hinge. The medial plate of the palatines is also deeply sunken, so that the distinctively lanceate vomer protrudes into the nasal cavity on a different plane than usual, well above the terete or shortly clavate maxillo-palatine processes… The pelvis is much shortened and broadened. The posterior wing of the contracted ilium, ischium and pubis extend out and down, not backwards as in other passerines. Modification to the anterior end of the ilium is still more unusual. The wings not only extend further back along either side of the synsacrum than in other song-birds, but expand completely over the top of it as well, forming a pair of very broad concave plates fused along a single, not double, medial crest. Each of these plates accommodates a greatly expanded Musculus iliotrochantericus caudalis (Baird 1985). The femur as well is short, thick and “dumb-bell”-shaped with enlarged facets to its anterior and posterior ends for attachment of the increased musculature reqired for lateral movement of the feet (Boles 1993).' (Schodde & Mason 1999).