Emus, Ostriches, Cassowaries, Rheas & Kiwi

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About Emus, Ostriches, Cassowaries, Rheas & Kiwi

Objectives of the group - To present an interesting, varied collection of high quality bird images belonging to the relevant families as described below. Images of museum specimens of the extinct species are welcome.

The Ratites are a diverse group of large, flightless birds of Gondwanan origin, most of them now extinct. Unlike other flightless birds, the ratites have no keel on their sternum—hence the name from the Latin ratis (for raft). Without this to anchor their wing muscles, they could not fly even if they were to develop suitable wings.

Most parts of the former Gondwana have ratites, or did have until the fairly recent past. Their closest living relatives are the tinamous of South America.

Some taxonomical systems consider the various families of ratites to be orders, but the system used here uses the order "Struthioniformes" to refer to all ratites. en.wikipedia.org/wiki/Ratites

The Emu (Dromaius novaehollandiae) is the largest bird native to Australia and the only extant member of the genus Dromaius. It is the second-largest extant bird in the world by height, after its ratite relative, the ostrich. There are three subspecies of Emus in Australia. The Emu is common over most of mainland Australia, although it avoids heavily populated areas, dense forest, and arid areas.

Although the Emu was long classified with its closest relatives, the cassowaries, in the family Casuariidae, part of the ratite order Struthioniformes, an alternate classification has been recently adopted which splits the Casuariidae into their own order, Casuariformes.

Two different Dromaius species were common in Australia before European settlement, and one additional species is known from fossil remains. The small emus—D. baudinianus and D. n. ater—both became extinct shortly after the arrival of Europeans. D. novaehollandiae diemenensis, a subspecies known as the Tasmanian Emu, became extinct around 1865. However, the mainland sub-species of D. novaehollandiae, remain common.

Their population size vary from decade to decade, largely dependent on rainfall; current estimates range from 625,000 to 725,000 birds, with 100,000–200,000 in Western Australia and the remainder mostly in New South Wales and Queensland. Emus were introduced to Maria Island off Tasmania and Kangaroo Island near South Australia during the 20th century. While the Maria Island population became extinct in the mid 1990s, the Kangaroo Island birds have established a breeding population.

There are three extant subspecies in Australia:

In the southeast, D. novaehollandiae novaehollandiae, with its whitish ruff when breeding;
In the north, D. novaehollandiae woodwardi, slender and paler; and
In the southwest, D. novaehollandiae rothschildi, darker, with no ruff during breeding.
Examination of the King island Emu's DNA shows it to be closely related to the mainland Emu and hence best treated as a subspecies.
en.wikipedia.org/wiki/Emu

The Cassowaries are ratites, very large flightless birds in the genus Casuarius native to the tropical forests of New Guinea, nearby islands and northeastern Australia. There are three extant species recognized today. The most common of these, the Southern Cassowary, is the third tallest and second heaviest living bird, smaller only than the ostrich and emu. en.wikipedia.org/wiki/Cassowary

The Ostrich was originally described by Linnaeus in his 18th-century work, Systema Naturae under its current binomial name. Its scientific name is derived from Latin, struthio meaning "Ostrich" and camelus meaning "camel", alluding to its dry habitat.

The Ostriches comprise one or two species of large flightless birds native to Africa, the only living member(s) of the genus Struthio. Some analyses indicate that the Somali Ostrich may be better considered a full species apart from the Common Ostrich, but most taxonomists consider it to be a subspecies.

Ostriches share the order Struthioniformes with the kiwis, emus, and other ratites. It is distinctive in its appearance, with a long neck and legs and the ability to run at maximum speeds of about 70 kilometres per hour (43 mph) the top land speed of any bird. The Ostrich is the largest living species of bird and lays the largest egg of any living bird (extinct elephant birds of Madagascar and the giant moa of New Zealand did lay larger eggs). en.wikipedia.org/wiki/Ostritch

Kiwi are flightless birds endemic to New Zealand, in the genus Apteryx and family Apterygidae.

At around the size of a domestic chicken, kiwi are by far the smallest living ratites and lay the largest egg in relation to their body size of any species of bird in the world. There are five recognised species, all of which are endangered; all species have been adversely affected by historic deforestation but currently large areas of their forest habitat are well protected in reserves and national parks. At present, the greatest threat to their survival is predation by invasive mammalian predators. en.wikipedia.org/wiki/Kiwi

The moa were eleven species (in six genera) of flightless birds endemic to New Zealand. The two largest species, Dinornis giganteus and Dinornis novaezelandiae, reached about 3.6 m (12 ft) in height with neck outstretched, and weighed about 230 kg (510 lb). All are members of the ratite group in the order Dinornithiformes. The eleven species of moa are the only wingless birds, lacking even the vestigial wings which all other ratites have. They were the dominant herbivores in New Zealand's forest, shrubland and subalpine ecosystems for thousands of years, and until the arrival of the Māori were hunted only by the Haast's Eagle. It is generally considered that most, if not all, species of Moa died out by Maori hunting and habitat decline before European discovery and settlement.

The kiwi were formerly regarded as the closest relatives of the moa, but comparisons of their DNA in a paper published in 2005 suggested moa were more closely related to the Australian emu and cassowary. However research published in 2010 found that the moa's closest cousins were not the emu and cassowary but smaller terrestrial South American birds called the tinamous which are able to fly. en.wikipedia.org/wiki/Moa

Aepyornis, the "elephant bird" of Madagascar, was the heaviest bird ever known. Although shorter than the tallest moa, a large Aepyornis could weigh over 450 kilograms (990 lb) and stand up to 3 metres (9.8 ft) tall.

Eggshell fragments similar to those of Aepyornis were found on the Canary Islands. The fragments date to the middle or late Miocene, and no satisfying theory has been proposed as to how they got there due to uncertainties about whether these islands were ever connected to the mainland. en.wikipedia.org/wiki/Ratites