Cockatiel

Cockatiel
Male
Female
Conservation status
Least Concern (IUCN 3.1)[1]
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 Weiro, is the smallest 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 assigned it to the Cockatoo subfamily Calyptorhynchinae (commonly known as Dark Cockatoos). It is, therefore, 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.

Taxonomy and etymology

Originally described by Scottish writer and naturalist 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. 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. This is only evident after the first molting, typically occurring about six to nine months after hatching: the male 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 will typically remain mostly gray, though also with an orange cheek patch. Additionally, the female 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

1927 Brehms Tierleben painting

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

Cockatiels are native to Australia, where they are found largely in arid or semi-arid country, but always near water. Largely nomadic, the species will move to where food and water is available.^[2] They are typically seen in pairs or small flocks.^[2] Sometimes, hundreds will flock around a single such body of water. To many 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.

Lifespan

The Cockatiel's lifespan in captivity is generally given as 15–20 years,^[6] though it is sometimes given as short as 10–15 years, and there are reports of Cockatiels living as long as 30 years, the oldest confirmed specimen reported being 36 years old.^[7] Diet and exercise are major determining factors in cockatiel lifespan.

Colour mutations

Fifteen different Cockatiel colour mutations are currently established in aviculture, including Grey, Pied, Pearled, Cinnamon, Whitefaced, Lutino, Albino (aka. Whitefaced Lutino) and Yellowcheeked Cockatiels.

Aviculture

Cockatiels are generally regarded as good pets. Like most other pets, the manner in which the animal is raised, handled, and kept along with inherited "personality" traits have a profound effect on the temperament of the animal. Some birds are quite gregarious and sociable while others can be shy, retreating to the back of the cage when an unfamiliar figure appears. If handled often and if they have a patient owner, cockatiels become tame very quickly compared to some other parrot species.

Gallery

Wild Cockatiels	A Wildtype (natural Grey coloured) Cockatiel showing excitement or interest by its erected crest.	A young pet ADMpied Cockatiel.	Near-completely clear (notice the small grey coloured feathers near the edge of its wing and it is rarer than most cockateils.) ADMpied Cockatiel.
3 week old Albino Cockatiel chick.	Cockatiel plumage glowing under a blacklight.	Cockatiels are social birds	A normal, gray, pet cockatiel offering his head to be petted.
Two cockatiels interacting.	Female Lutino Cockatiel

See also

• Cockatiel (aviculture)
• Cockatiel colour genetics

Footnotes

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
• 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
• Martin, Terry (2002). A Guide To Colour Mutations and Genetics in Parrots. ABK Publications. ISBN 0-9577024-6-9. 
• Hayward, Jim (1992). The Manual of Colour Breeding. The Aviculturist Publications. ISBN 0-9519098-0-0. 

External links

• Cockatiels at the Open Directory Project
• Inte ONSMAN's MUTAVI Research and Advice Group
• Clive Hesford's Cockatiel Parakeet section from The Genetics of Colour in the Budgerigar and other Parrots website