Ortònice australiano

Identificazione

Logrunners as a group are characterised by their distinctive tail feathers where the rachis (or central shafts) of the tail feathers protrude and are stiffened. The broad tail of the bird is less than four inches (10 cm) in length and the strong protruding rachis at the ends of the tail feathers are almost void of the usual barbs, giving the feather the appearance of spines. This appearance gives rise to some of the common names for the bird such as spine-tail or spine-tailed logrunner.<p>There appears to be some debate about the number of tail feathers possessed by the Australian logrunner. For example, some references state that the logrunner only has 10 tail feathers whilst other references describe the bird as having 12 tail feathers. Most birds are described as having 12 tail feathers but there are notable exceptions to this.<p>The logrunner is not unique in having atypical tail feather structures. Other birds, such as the greater melampitta (Melampitta gigantea), also have spiny and stiffened tail feathers, but not to the same extent as the logrunner. Birds such as creepers, woodpeckers, swifts and penguins are also known to use their modified tail feathers as braces and supports.<p>The logrunner's head and back are a reddish-brown colour; the wings are mainly black; and the tail is dark brown. The wing-coverts are tipped with grey and the eyebrow and ear-coverts grey. The throat, breast and abdomen feathers are white. In the female, the throat is an orange-rufous colour. The male is also larger than the female.

Tassonomia

The Australian logrunner is a Passeriform in the family Orthonychidae. It is one of only three species within the Orthonyx genus; the other two are the chowcilla (Orthonyx spaldingii) from northern Queensland and the New Guinean logrunner (Orthonyx novaeguineae) from Papua New Guinea.

Nome scientifico

Orthonyx temminckii

Autorità

Ranzani, 1822

Ordine

Passeriformi

Famiglia

Orthonychidae

Genere

Orthonyx

Areale e habitat

The Australian logrunner is found in South Eastern Australia from the Illawarra district in NSW to the Bunya Mountains in Queensland. Its preferred habitat is characterised by the leafy floor of rainforests, rich with scattered logs, forest debris, ferns, vines and saplings.

Migrazione

Resident species

Comportamento

The most characteristic behaviour of the logrunner is its foraging technique that involves the bird propping against its spiny tail and then scrapping or throwing leaf debris aside with its feet. Once the larger debris is removed, logrunners then use their tail as a brace and scratch the exposed soil looking for food. This scratching leaves 'soup-plate' depressions in the debris that are about 150 mm in diameter.<p>The sideways sweeping action of the legs whilst foraging is unique to logrunners and is possible due to the distinctive structure of the logrunner's pelvis and hind legs. The pelvis is short and broad and the femur is stout with strongly developed projections that support the attachment of the strong muscles needed to support its foraging technique.<p>Logrunners are described as noisy birds with performances of loud songs and calls, especially in the mornings. These songs and calls are believed to have either a territorial or sexual function.

Conservazione

Tendenza della popolazione

declining