The wedge-tailed eagle (Aquila audax) is the largest bird of prey in the continent of Australia. It is also found in southern New Guinea to the north and is distributed as far south as the state of Tasmania. Adults of this species have long, broad wings, fully feathered legs, an unmistakable wedge-shaped tail, an elongated maxilla, a strong beak and powerful feet. The wedge-tailed eagle is one of 12 species of large, predominantly dark-coloured booted eagles in the genus Aquila found worldwide. Genetic research has clearly indicated that the wedge-tailed eagle is fairly closely related to other, generally large members of the Aquila genus. A large brown-to-black bird of prey, it has a maximum reported wingspan of and a length of up to .
The wedge-tailed eagle is one of its native continent's most generalized birds of prey. They reside in most habitats present in Australia, ranging from desert and semi-desert to plains to mountainous areas to forest, even sometimes tropical rainforests. Preferred habitats, however, tend towards those that have a fairly varied topography including rocky areas, some open terrain and native woodlots such as Eucalyptus stands.
The wedge-tailed eagle is one of the world's most powerful avian predators. Although a true generalist, which hunts a wide range of prey including birds, reptiles and, rarely, other taxa, the species is by and large a mammal predator. The introduction of the European rabbit (Oryctolagus cuniculus) has been a boon to the wedge-tailed eagle and they hunt these and other invasive species in large volume, although the wedge-tailed eagle otherwise generally lives off of marsupials, including many surprisingly large macropods. Additionally, wedge-tailed eagles often eat carrion, especially while young. The species tends to pair for several years, possibly mating for life.
Wedge-tailed eagles usually construct a large stick nest in an ample tree, normally the largest in a stand, and typically lay two eggs, although sometimes one to four. Usually, breeding efforts manage to produce one or two fledglings which, after a few months more, tend to disperse widely. Nesting failures are usually attributable to human interference such as logging activity and other alterations, which both degrade habitats and cause disturbances. This species is known to be highly sensitive to human disturbance at the nest, which may lead to abandonment of the young.
Although historically heavily persecuted by humans through poisoning and shooting, mostly for alleged predation on sheep, wedge-tailed eagles have proved to be exceptionally resilient, and have quickly rebounded to similar or even higher than pre-colonization numbers, thanks in part to humans inadvertently providing several food sources such as rabbits and large volumes of roadkills.
Taxonomy
The species was first described by the English ornithologist John Latham in 1801 under the binomial name Vultur audax. The genus Vultur is today used only for a completely unrelated bird of the New World vulture family, the Andean condor (Vultur gryphus). The specific scientific name for the species audax, is derived from the Latin audac, meaning "bold", indicative of their perceived disposition, perhaps when hunting although the species is, in general, highly wary, and even timid, around humans. At one time, the wedge-tailed eagle was classified in it is own monotypical genus Uroaetus, perhaps due to its unique form.
However, the species is clearly quite similar in many aspects of its morphology, appearance, behaviour and life history, to other species in the Aquila genus. The eagles of the Aquila genus are part of the subfamily Aquilinae, within the larger Accipitridae family. The subfamily is commonly referred to as booted eagles or sometimes as true eagles. Those species may be distinguished from most other accipitrids by the feathering covering their legs, regardless of distribution. With some 39 or so species, the Aquilinae is present on every continent except Antarctica.
By a variety of phylogenetic testing, largely via Mitochondrial DNA and Nuclear DNA genes, it has been determined that the wedge-tailed eagle clusters with certain other Aquila eagles. The species found to share the most genetic similarities is the Verreaux's eagle (Aquila verreauxii) of Africa. However, the Gurney's eagle (Aquila gurneyi), a mostly allopatric but outwardly fairly similar eagle, is clearly a very close relation of the wedge-tailed eagle and the two are likely sister species, most probably originating from the same radiation across the Indo-Pacific region.