Cockatiel

The Cockatiel (Nymphicus hollandicus), also known as the Quarrion and the Weero, is a diminutive Cockatoo endemic to Australia and prized as a household pet.

The only members of their genus, Cockatiels are now biologically classified as the smallest of the Cockatoo Family. These sweet-tempered birds are valued throughout the world as pets due to their gentle and sociable nature. These birds are found across the outback regions of inland Australia, and favour the Australian wetlands, scrublands, and bush lands.

The Cockatiel's distinctive pointed crest is held erect when startled or excited, while a crest slightly tilted indicates a relaxed state of mind. The Wildtype (natural colored) Cockatiel's plumage is generally mid-grey, lighter underneath, with an almost perfectly round orange patch on both ear coverts (usually referred to as the "cheek patches") and a prominent white flash on the outer edge of each wings.

This species is sexually-dimorphic only in adulthood while immature cockatiels of both genders display the dimorphic features typical of adult hens. A row of clear colored (cream, white or yellow) spots can be found underneath the wings of hens as well as immatures of both genders, but is always absent in cocks. Hens as well as immature birds of both genders display either barred, dotted and/or striped (i.e. cream & beige, white and grey, yellow and brown) underside of tail feathers while cocks always display solid colored (i.e. beige, black, brown, grey, silver or white) underside of tail-feathers.

Contrary to the common belief, adult Cockatiels can be visually-sexed by their crest, head and/or ear coverts colorations only in Wildtype (natural colored) specimens. Where Wildtype cocks display near entirely yellow crests, faces and orange cheek patches, Wildtype hens and immatures of both genders display basically grey crests and faces with minor yellow streaks as well as greyish-orange cheek patches. The latter dimorphic features (basically clear faces in cocks versus basically dirty faces in hens and immatures of both genders) are retained in most primary mutations except in every ADMpied & Ino varieties.

The Lutino mutation, for example, which completely lacks eumelanin pigment (enabling black, brown, grey colours and tones), being basically yellowish-white with orange cheek-patches in most specimens although some rare Lutino lineages are near-entirely yellow with orange cheek patches. Adult female Lutinos as well as immature Lutinos of both genders display yellow bars, dots and/or stripes on the underside of their tail feathers while mature males always display solid coloured underside of tail-feathers which are pure white in adult male specimens.

Only in the genuine Albino (often called Whitefaced Lutino or Whitefaced Ino) and the ADMpied (simply known as Pied and/or Recessivepied) mutation and all of it's numerous varieties (i.e. Cinnamon Pied, Opaline Pied aka Pearl Pied, Whitefaced Pied) is there no visual-sexing possible. This is because throughout species, genuine Albino specimens are always entirely pure-white and because the ADMpied (AntiDiMorphic Pied) gene always negates the male's ability from ever displaying his species' sexual-dimorphic features.

The Cockatiel's lifespan in captivity is generally given as 15-20 years, though it is sometimes given as short as 12-15 years and there are reports of Cockatiels living as long as 30 years, the oldest confirmed specimen reported being 35 years old when it died.
 

Placed in its own Genus, the Cockatiel's scientific name Nymphicus hollandicus reflects the experience of one of the earliest groups of Europeans to see Cockatiels in their native habitat. Travellers thought they were so beautiful that they named them after the mythical creatures, the nymphs (Nymphicus means literally "little nymph"). The species name refers to New Holland, an old name for Australia. It's biological relationship had long been disputed; it was usually placed into a monotypic subfamily Nymphicinae or even allied with the Platycercinae aka broad-tailed Parakeets.

The Cockatiel is now biologically classified as a genuine member of the Cacatuidae on account of sharing everyone of the Cockatoo Family's biological features, including the erectable crest, a gallbladder, powder down patches, suppressed cloudy-layer (which enables Lories, Lorikeets & typical Parrot species display of structural colours such as aquas, blues, greens, purples & turquoises) and facial feathers covering the sides of the beak, which are rarely - if ever - found outside the Cacatuidae family. In contrast to most Cockatoos, the Cockatiel has long tail feathers (hence the descriptive Parakeet 2nd part of it's common name), roughly making up half of its total length. At 300 mm to 330 mm, the Cockatiel is the smallest & only Parakeet (long-tailed) type of all Cockatoo species which ranges between 500 mm to 600 mm in length.

Mitochondrial 12S rRNA sequence data has finally resolved the question of its affinities by placing it amongst the Calyptorhynchinae(dark Cockatoo) Subfamily. The unique, Parakeet morphological feature is a consequence of the decrease in size and accompanying change of ecological niche. Despite the latter unique adaptation, the dark plumage, the dimorphic features and the fact that a hen Cockatiel has very recently been accidentally Hybridized with a cock Eolophus roseicapillus (Galah aka rose-breasted Cockatoo) producing one very healthy (although most probably sterile) & well offspring (see direct-link below for full story, pictures & video clip) are all clear morphological indications of it's genuine belonging among Calyptorhynchinae (dark Cockatoo) Subfamily.

Sequence analysis of intron 7 of the nuclear β-fibrinogen gene, on the other hand, indicates that it may be as distinct yet as to warrant recognition of the Nymphicinae rather than inclusion of the genus in the Calyptorhynchinae.