Logrunner

The Orthonychidae is a family of birds with a single genus, Orthonyx, which comprises three species of passerine birds endemic to Australia and New Guinea, the Logrunners and the Chowchilla. Some authorities consider the Australian family Cinclosomatidae to be part of the Orthonychidae. The three species use their stiffened tails to brace themselves when feeding.

The Lesser Melampitta (Melampitta lugubris) may also belong here.

The Australian Logrunner, Orthonyx temminckii, is from south-eastern Australia, where it is very local in its distribution, and strictly terrestrial in its habits. The wings are, however, barred with white, and the chin, throat and breast are in the male pure white, but of a bright reddish-orange in the female. The remiges are very short, rounded and much incurved, showing a bird of weak flight. The rectrices are very broad, the shafts stiff, and towards the tip divested of barbs. The population which is found locally in New Guinea is now generally considered a separate species, the New Guinea Logrunner, Orthonyx novaeguineae.

The Chowchilla, Orthonyx spaldingii, from north-east Queensland is of much greater size than the Logrunner, and with a jet-black plumage, the throat being white in the male and orange-rufous in the female.

Both are semi-terrestrial birds of weak flight, and build a domed nest on or near the ground. Insects and larvae are their chief food, and the males are described as performing dancing antics like those of the lyrebirds.

The fossil record does not much help to determine the affiliations of the Orthonychidae. Three prehistoric species are known to science. The very large Orthonyx hypsilophus from Green Waterhole Cave and an undescribed species found in Pyramids Cave which was a bit smaller than the logrunner are probably of Late Pleistocene age. Orthonyx kaldowinyeri\\ is known from Middle or Late Miocene deposits of Riversleigh; it is the oldest and smallest species known to date (Boles, 1993).