Family CORCORACIDAE Mathews, 1927

Museums

Regional Maps

• Corcoracidae Mathews, G.M. 1927. The Birds of Australia. London : Witherby Vol. 12 pp. 226-454.

  Type genus:

   Corcorax Lesson, 1830.

Introduction

This family is an old endemic group of 'mud nesters' consisting of two species in monotypic genera (Corcorax and Struthidea). Each species comprises two subspecies. Both species are strongly gregarious and terrestrial with absorbing behavioural traits. Noisy flocks are usually formed of up to 20 individuals for the genus Corcorax, while Struthidea has upwards of a dozen. At feeding concentrations the numbers may increase due to the amalgamation of two or more groups. Struthidea has been found about human habitation in numbers exceeding 100 individuals.

Both genera have stout bills and legs well adapted for a terrestrial existence. The sclerotic ring about the iris differs from other passerines in that it can be embellished with blood to present a 'bulge blazing red in excitement or aggression' in Corcorax and to a lesser degree in Struthidea. Skull formation differs between the two, the smaller species having a more heavily ossified appearance. 'Behaviour and nidification provide sounder clues to intrinsic though not extrinsic — relationships than structural morphology' (Schodde & Mason 1999).

Corcoracids are principally insectivores, feeding by gleaning, probing, pouncing and snatching, although small mammals have been noted in their diet (Barker & Vestjens 1990). The larger Corcorax probe and search litter using their lengthy bill whereas the shorter billed Struthidea pick and scratch at the surface (Schodde & Mason 1999). The gregariousness of the group allows them a number of features ensuring their survival. These communal groups are aggressive to potential predators; they also exhibit cooperative breeding traits, where a single nest may have a number of females contributing to the clutch and domestic behaviour.

The distribution is principally associated with woodlands throughout south-eastern and northern Australia although Corcorax may enter forested environments and Struthidea utilises shrublands. They construct large, deep mud nests; fine grasses and feathers form a lining in the nest cavity. This nest is built on a horizontal branch by a number of individuals within the family group. Eggs, numbering up to eight, are creamy white, marked overall with darker brown or greyish dots and blotches. As a group they are playful, behaviour that is especially apparent in Struthidea.

Database Notes

Although Struthideinae Mathews, 1924 (type genus Struthidea Gould, 1837) is senior to Corcoracinae Mathews, 1927 (type genus Corcorax Gould, 1837) as the valid name for this family when both Corcorax Gould and Struthidea Gould are included in it, Corcoracidae is kept in deference to Bock, Bull. AMNH 222(1994)221

General References

Barker, R.D. & Vestjens, W.J.M. 1990. The Food of Australian Birds. 2 Passerines. Canberra : CSIRO Australia.

Schodde, R. & Mason, I.J. 1999. The Directory of Australian Birds : Passerines. A Taxonomic and Zoogeographic Atlas of the Biodiversity of Birds in Australia and its Territories. Collingwood, Australia : CSIRO Publishing x 851 pp.

History of changes