Cockatiel

Cockatiel
Conservation status
Least Concern
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Aves
Order:	Psittaciformes
Family:	Cacatuidae
Subfamily:	Calyptorhynchinae
Genus:	Nymphicus Wagler, 1832
Species:	N. hollandicus
Binomial name
Nymphicus hollandicus (Kerr, 1792)
Cockatiel range (in red; all-year resident)
Synonyms
Psittacus hollandicus Kerr, 1792 Leptolophus hollandicus

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.

Description

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 coloured) 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 in only adulthood while immatures of both genders display the hens' typical dimorphic features. A row of clear coloured (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 of both genders display either barred, dotted &/or striped (i.e. cream & beige, white & grey, yellow & brown...) underside of tail feathers while cocks always display solid coloured (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 &/or ear coverts colourations only in Wildtype (natural coloured) specimens ! Where Wildtype cocks display near entirely yellow crests, faces & orange cheek patches. While Wildtype hens & immatures of both genders display basically grey crests & faces with minor yellow streaks as well as greyish-orange cheek patches.

Although +/- boldly obvious ; the latter dimorphic features (basically clear faces in cocks versus basically dirty faces in hens & immatures of both genders) are retained in each & every primary mutations.

i.e. the Lutino mutation, which completely lacks eumelanin pigment (enabling black, brown, grey colours & 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 &/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) & the ADMpied (simply known as Pied &/or Recessivepied) mutation & 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 & 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.

Taxonomy

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 closest to the "dark Cockatoos" of the genus Calyptorhynchus. 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 and 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) which produced 1 sterile but otherwise very healthy & well offspring (see direct-link below for full story, pictures & video clip) are all clear morphological indications of it's genuine belonging amongst dark Cockatoos.

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.

Distribution and habitat

Cockatiel are native only to Australia where they are found largely in arid or semi-arid country, but always near water. Sometimes hundreds will flock around a single such body of water. To farmers' dismay, they often eat cultivated crops. They are absent from the most fertile southwest and southeast corners of the country, the deepest Western Australian deserts, and Cape York Peninsula. They are the only Cockatoo species which can sometimes reproduce in the end of their first year.

Aviculture

Pied/Pearl Mutation Cockatiel

Cockatiel, along with the Budgerigar, are among the most popular pet bird species. Today all Cockatiels available in the pet-trade are/were captive-bred, as Australia no longer permits the export of native wildlife, whether endangered or not.

About 15 primary mutations have occurred & are +/- established in the species and enables the production of tens & tens of different combinations. Mutations includes ;

• ADMpied (aka Recessivepied)
• Ashenfallow (eka 'Recessivesilver')
• Bronzefallow)
• Cinnamon, Dominantsilver
• Dilute (eka 'Pastelsilver')
• Dominantsilver (aka 'Ashendilute')
• Edgeddilute (eka 'Spangledsilver')
• Faded
• Ino
• NSLino
• Opaline (cka Pearl)
• Palefaced (eka 'Pastelfaced')
• Pallid (ika 'Platinum &/or SL Platinum')
• Whitefaced
• Dominant & SL (Sex-Linked) Yellowcheeked
• Yellow-suffused (eka 'Emerald &/or Olive')

Cockatiels can form strong bonds with their owners. Otherwise quiet birds will frequently make contact calls with their owners, calls that sometimes can be quite loud if the person is out of sight. The cockatiel can grow so attached to its owner that it may try to 'protect' the owner from anyone that tries to come near it by biting or hissingCockatiels must be acquainted with the entire family, in order to assure even temperament toward all. A scared 'tiel will choose flight over fight most of the time, thus creating a chance for injury (i.e. flying into a glass door). Their popularity as pets is in part because of their calm and timid temperament, to the point that they can even be bullied by smaller but more confident birds such as Budgerigars. Great care and supervision should be provided when mixing cockatiels with other birds. It is not uncommon at all for a larger or smaller bird to maim the cockatiel, creating life-long disabilities and potentially life threatening injuries. However, some cockatiels will defend themselves.

Although cockatiels are part of the parrot order, they are better at imitating whistles than speech. Some do learn to repeat phrases, and the males are generally better at mimicry than the femalesCockatiel speech, often comes out as a "whistle", when they do annunciate, the voice is very soft and hard to make out. Cockatiels can mimic many sounds, for example the bleep of a car alarm, a ringing telephone, or the calls of other bird species such as blue jays or chickadees and loud weather like thunder. They can also mimic other pets such as dogs, occasionally barking back.

Colour Mutations

In the wild, cockatiels are naturally grey with white wing patches and yellow and orange on their heads. Colour mutations are desirable for show and some owners, however a number of these are sex-linked and/or recessive. For example, the lutino mutation is such that the individual does not produce melatonin, resulting in a phenotype of no grey coloration upon the body. The genotype is XL Y (female cockatiel with lutino gene linked to the male chromosome X) or XL XL (male cockatiel with lutino linked to both male chromosomes). Male cockatiels with a genotype of XL X carry the lutino gene, but do not express it and will appear normal grey. (Note that in birds, XY denotes female, while XX is male; some ornithologists use different letters such as ZW for female and ZZ for male.)Lutinos are known for having a "bald patch", directly below their crest.

A pet lutino cockatiel. Note the lack of dark pigment, including in the eyes.

Mutations can appear both individually or in a wide variety of combinations such as lutino pearl, whiteface pied, lutino pied and whiteface lutino (which is often called albino, but is not a true form of albinism). Still fairly hard to find is the rather new 'olive' mutation. An olive cockatiel does not actually have green pigment to its plumage, but rather an overlapping pattern of yellow and grey that create the illusion of a greenish cast.

Many mutations retain the black eyes, beak, nails and grey feet of the normal grey cockatiels, however the lutino, cinnamon and fallow mutations have pink to deep plum red eyes, pink toenails and feet, and a horn coloured beak. While most mutations persist into adulthood for all cockatiels, certain mutations like pearl are molted out in the males and retained in the adult females. Sex-linked mutations such as lutino and cinnamon have a higher ratio of female offspring to male due to the mode of inheritance from parents to offspring. As lutino and albino cockatiels lack the pigment melanin, these birds will have red eyes.

Breeding

Cockatiels are a popular choice for amateur parrot breeding along with budgerigars. This is due to both the ease of getting the birds to breed (they have no inhibitions whatsoever) and the fairly low cost of the equipment needed. Generally a clutch consists of 5-7 eggs, each approximately the size of one's thumbnail. Eggs are laid once every two days and incubate for about 19 days. Hatchings are weaned in 4 weeks, and can fly around 2 months. Puberty (adolescence) is reached around 9 months of age while adulthood is reached around 12 months in males &/or 15 months in females.

Male cockatiels are very protective and nurturing of their offspring and are known to be very capable of raising their newborns if the mother is unable to.

Some female cockatiels also lay eggs without fertilization (as do chickens; both infertile). In this case, the owner should just leave the eggs alone until the bird stops sitting on them, after which the eggs can be removed. To prevent laying, one can keep the cockatiel in more darkness per day, such as by covering it up for the night earlier and leaving it covered longer in the morning. Like all parrots, cockatiels of either gender can grow to see their owner or a toy as a mate, engage in courtship and mating behavior including territoriality, and females may lay infertile eggs.

The Cockatiel has recently been shown to be capable of hybridizing with the Galah, producing offspring described by the media as 'Galatiels'.

Gallery

• A Cockatiel with an erect crest
  A Cockatiel with an erect crest
• Female hand-raised Cockatiel of typical colouring, age 15
  Female hand-raised Cockatiel of typical colouring, age 15
• A young pet Cockatiel.
  A young pet Cockatiel.
• 
  Cockatiels mating
• 
  A captive-bred lutino Cockatiel
• Whiteface lutino Cockatiel chick, age three weeks
  Whiteface lutino Cockatiel chick, age three weeks

See also

• Whiteface Lutino Cockatiel
• Parrot harness

References

• 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

• Template:IUCN2006 Database entry includes justification for why this species is of least concern

• Brown, D.M. & Toft, C.A. (1999): Molecular systematics and biogeography of the cockatoos (Psittaciformes: Cacatuidae). Auk 116(1): 141-157.

• Flegg, Jim (2002): Photographic Field Guide: Birds of Australia. Reed New Holland, Sydney & London. ISBN 1-876334-78-9