Nymphicus hollandicus Cladus: Eukaryota Name Nymphicus hollandicus (Kerr, 1792) Vernacular names --------- The Cockatiel (Nymphicus hollandicus), also known as the Quarrion and the Weiro, is the smallest and genuinely miniature cockatoo endemic to Australia. They are prized as a household pet and companion parrot throughout the world and are relatively easy to breed. As a caged bird, cockatiels are second only in popularity to the Budgerigar.[2] The cockatiel is the only member of the genus Nymphicus. It was previously considered a crested parrot or small cockatoo. However, more recent molecular studies have settled the debate. These indicate that the Cockatiel belongs in the Cockatoo Subfamily Calyptorhynchinae (commonly known as Dark Cockatoos). They are hence now classified as the smallest of the Cacatuidae (Cockatoo family). Cockatiels are native to the outback regions of inland Australia, and favour the Australian wetlands, scrublands, and bush lands. Originally described by Scottish writer and naturalister Robert Kerr in 1793 as Psittacus hollandicus, the Cockatiel was moved to its own genus, Nymphicus, by Wagler in 1832. Its genus name reflects the experience of one of the earliest groups of Europeans to see the birds in their native habitat; the travelers thought the birds were so beautiful that they named them after mythical nymphs. (Nymphicus literally means "little nymph.") The specific name hollandicus refers to New Holland, a historic name for Australia. Its biological relationship had long been argued; it is now classified into a monotypic subfamily Nymphicinae but had sometimes in the past been misclassified among the Platycercinae, the broad-tailed Parakeets. This issue has now been settled with molecular studies. A 1984 study of protein allozymes signalled its closer relationship to cockatoos than to parrots,[3] and Mitochondrial 12S rRNA sequence data[4] places it amongst the Calyptorhynchinae (Dark Cockatoos) subfamily. The unique, Parakeet (meaning LONG-tailed Parrot) morphological feature is a consequence of the decrease in size and accompanying change of ecological niche. Sequence analysis of intron 7 of the nuclear ?-fibrinogen gene, on the other hand, indicates that it may yet be distinct enough as to warrant recognition of the Nymphicinae rather than inclusion of the genus in the Calyptorhynchinae.[5] The Cockatiel is now biologically classified as a genuine member of Cacatuidae on account of sharing all of the Cockatoo family's biological features, namely, the erectile crest, a gallbladder, powder down, suppressed cloudy-layer (enabling Lories, Lorikeets (long-tailed Lories), Parakeets and typical Parrot species' display of structural colours such as aquas, blues, greens, purples and turquoises), and facial feathers covering the sides of the beak, all of which are rarely found outside the Cacatuidae family. Sexual dimorphism All wild cockatiel (also known as the Normal Grey Cockatiel) chicks and juveniles are phenotypically female, and virtually indistinguishable from the time of hatching until their first molting. They display horizontal yellow stripes or bars on the ventral surface of their tail feathers, yellow spots on the ventral surface of the primary flight feathers of their wings, a gray colored crest and face, and a dull orange patch on each of their cheeks. Adult cockatiels are sexually dimorphic, though to a lesser degree than many other avian species. The birds of both sexes replace their feathers in a process called molting. The first molting typically occurs at about six to nine months after hatching. It is only after this first molting that males can readily be distinguished from females. At the first molting, the male (or cock) loses the white or yellow barring and spots on the underside of his tail feathers and wings. The gray feathers on his cheeks and crest are replaced by bright yellow feathers, while the orange cheek patch becomes brighter and more distinct. The face and crest of the female (or hen) will typically remain mostly gray, though also with an orange cheek patch. Additionally, the hen commonly retains the horizontal barring on the underside of her tail feathers. The color in cockatiels is derived from two pigments: Melanin (which provides the gray color in the feathers, eyes, beak, and feet), and lipochromes (which provide the yellow color on the face and tail and the orange color of the cheek patch). The gray color of the melanin overrides the yellow and orange of the lipochromes when both are present. The melanin content decreases in the face of the males as they mature, allowing the yellow and orange lipochromes to be more visible, while an increase in melanin content in the tail causes the disappearance of the horizontal yellow tail bars. In addition to these visible characteristics, the vocalization of adult males is typically louder and more complex than that of females. Portrayal The Cockatiel's distinctive erectile crest expresses the animal's state of being. The crest is dramatically vertical when the cockatiel is startled or excited, gently oblique in its neutral or relaxed state, and flattened close to the head when the animal is angry or defensive. The crest is also held flat but protrudes outward in the back when the cockatiel is trying to appear alluring or flirtatious. In contrast to most Cockatoos, the Cockatiel has long tail feathers roughly making up half of its total length. At 300 mm to 330 mm (12 to 13 ins), the Cockatiel is the smallest and only parakeet type of Cockatoo species. The latter ranging between 300 mm to 600 mm (12–24 in) in length. The "Normal Grey," or "Wild-type" cockatiel's plumage is primarily grey with prominent white flashes on the outer edges of each wing. The face of the male is yellow or white, while the face of the female is primarily grey or light grey, and both sexes feature a round orange area on both ear areas, often referred to as "cheek patches." This orange colouration is generally vibrant in adult males, and often quite muted in females. Visual sexing is often possible with this variant of the bird. Distribution and habitat Aviculture
1. ^ BirdLife International (2008). Nymphicus hollandicus. In: IUCN 2008. IUCN Red List of Threatened Species. Downloaded on 25 October 2008.
* Astuti, Dwi (2004?): A phylogeny of cockatoos (Aves: Psittaciformes) inferred from DNA sequences of the seventh intron of nuclear β-fibrinogen gene. Doctoral work, Graduate School of Environmental Earth Science, Hokkaido University, Japan. PDF fulltext Source: Wikispecies, Wikipedia: All text is available under the terms of the GNU Free Documentation License |
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