The cockatiel (; ''Nymphicus hollandicus''), also known as weiro (also spelt weero), or quarrion, is a medium-sized

parrot Parrots, also known as psittacines (), are birds of the roughly 398 species in 92 genera comprising the order Psittaciformes (), found mostly in tropical and subtropical regions. The order is subdivided into three superfamilies: the Psittacoid ...

that is a member of its own branch of the

cockatoo A cockatoo is any of the 21 parrot species belonging to the family Cacatuidae, the only family in the superfamily Cacatuoidea. Along with the Psittacoidea (true parrots) and the Strigopoidea (large New Zealand parrots), they make up the ord ...

family

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsew ...

Australia Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...

. They are prized as household

pet A pet, or companion animal, is an animal kept primarily for a person's company or entertainment rather than as a working animal, livestock, or a laboratory animal. Popular pets are often considered to have attractive appearances, intelligence, ...

s and

companion parrot A companion parrot is a parrot kept as a pet that interacts abundantly with its human counterpart. Generally, most species of parrot can make excellent companions, but must be carefully managed around other common pet species like dogs and cats a ...

s throughout the world and are relatively easy to breed. As a caged bird, cockatiels are second in popularity only to the

budgerigar The budgerigar ( ; ''Melopsittacus undulatus''), also known as the common parakeet or shell parakeet, is a small, long-tailed, seed-eating parrot usually nicknamed the budgie ( ), or in American English, the parakeet. Budgies are the only spe ...

. The cockatiel is the only member of the

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

''Nymphicus''. It was previously unclear whether the cockatiel was a crested

parakeet A parakeet is any one of many small to medium-sized species of parrot, in multiple Genus, genera, that generally has long tail feathers. Etymology and naming The name ''parakeet'' is derived from the French wor''perroquet'' which is reflec ...

or small cockatoo; however, more recent molecular studies have assigned it to its own subfamily, ''Nymphicinae''. It is, therefore, now classified as the smallest of the

Cacatuidae A cockatoo is any of the 21 parrot species belonging to the family (biology), family Cacatuidae, the only family in the superfamily Cacatuoidea. Along with the Psittacoidea (true parrots) and the Strigopoidea (large New Zealand parrots), the ...

(cockatoo family). Cockatiels are native to Australia, favouring the Australian wetlands, scrublands, and bushlands.

Taxonomy and etymology

Originally described by Scottish writer and naturalist Robert Kerr in 1793 as ''Psittacus hollandicus'', the cockatiel (or cockateel) was moved to its own genus, ''Nymphicus'', by Wagler in 1832. Its genus name reflects the experience of one of the earliest groups of

Europe Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a Continent#Subcontinents, subcontinent of Eurasia ...

ans to see the birds in their native

habitat In ecology, the term habitat summarises the array of resources, physical and biotic factors that are present in an area, such as to support the survival and reproduction of a particular species. A species habitat can be seen as the physical ...

; the travellers thought the birds were so beautiful that they named them after mythical

nymphs A nymph ( grc, νύμφη, nýmphē, el, script=Latn, nímfi, label=Modern Greek; , ) in ancient Greek folklore is a minor female nature deity. Different from Greek goddesses, nymphs are generally regarded as personifications of nature, are typ ...

. The

specific name Specific name may refer to: * in Database management systems, a system-assigned name that is unique within a particular database In taxonomy, either of these two meanings, each with its own set of rules: * Specific name (botany), the two-part (bino ...

''hollandicus'' refers to New Holland, a historic name for Australia. Its biological relationships were for a long time uncertain; it is now placed in a

monotypic In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unispec ...

subfamily In biological classification, a subfamily (Latin: ', plural ') is an auxiliary (intermediate) taxonomic rank, next below family but more inclusive than genus. Standard nomenclature rules end subfamily botanical names with "-oideae", and zoologi ...

Nymphicinae, but was sometimes in the past classified among the

Platycercinae Platycercinae is a subfamily of birds belonging to the family Psittaculidae that inhabit Oceania. It consists of two tribes, the ground parrots and allies ( Pezoporini) and the many species of broad-tailed parrot ( Platycercini). Genera Tribe P ...

, the broad-tailed parrots. This issue was settled with molecular studies. A 1984 study of protein allozymes signalled its closer relationship to cockatoos than to other parrots, and

mitochondrial A mitochondrion (; ) is an organelle found in the cells of most Eukaryotes, such as animals, plants and fungi. Mitochondria have a double membrane structure and use aerobic respiration to generate adenosine triphosphate (ATP), which is use ...

12S

rRNA Ribosomal ribonucleic acid (rRNA) is a type of non-coding RNA which is the primary component of ribosomes, essential to all cells. rRNA is a ribozyme which carries out protein synthesis in ribosomes. Ribosomal RNA is transcribed from ribosoma ...

sequence In mathematics, a sequence is an enumerated collection of objects in which repetitions are allowed and order matters. Like a set, it contains members (also called ''elements'', or ''terms''). The number of elements (possibly infinite) is calle ...

data places it among the

Calyptorhynchinae Described by French naturalist Anselme Gaëtan Desmarest in 1826, the genus ''Calyptorhynchus'' has two species of cockatoos. They are all mostly black in colour, and the taxa may be differentiated partly by size and partly by small areas of red, ...

(dark cockatoos)

. The unique,

(meaning long-tailed parrot) morphological feature is a consequence of the decrease in size and accompanying change of

ecological niche In ecology, a niche is the match of a species to a specific environmental condition. Three variants of ecological niche are described by It describes how an organism or population responds to the distribution of resources and competitors (for ...

. Sequence analysis of

intron An intron is any nucleotide sequence within a gene that is not expressed or operative in the final RNA product. The word ''intron'' is derived from the term ''intragenic region'', i.e. a region inside a gene."The notion of the cistron .e., gene. ...

7 of the

nuclear Nuclear may refer to: Physics Relating to the nucleus of the atom: * Nuclear engineering *Nuclear physics *Nuclear power *Nuclear reactor *Nuclear weapon *Nuclear medicine *Radiation therapy *Nuclear warfare Mathematics *Nuclear space *Nuclear ...

''β''-

fibrinogen Fibrinogen (factor I) is a glycoprotein complex, produced in the liver, that circulates in the blood of all vertebrates. During tissue and vascular injury, it is converted enzymatically by thrombin to fibrin and then to a fibrin-based blood clo ...

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

. The cockatiel is now biologically classified as a genuine member of

on account of sharing all of the cockatoo family's biological features, namely, the erectile crest, a

gallbladder In vertebrates, the gallbladder, also known as the cholecyst, is a small hollow organ where bile is stored and concentrated before it is released into the small intestine. In humans, the pear-shaped gallbladder lies beneath the liver, although ...

powder down The down of birds is a layer of fine feathers found under the tougher exterior feathers. Very young birds are clad only in down. Powder down is a specialized type of down found only in a few groups of birds. Down is a fine thermal insulator and ...

, suppressed cloudy-layer (which precludes the display of blue and green structural colours), and facial feathers covering the sides of the beak, all of which are rarely found outside the family Cacatuidae. This biological relation to other cockatoos is further supported by the existence of at least one documented case of a successful

hybrid Hybrid may refer to: Science * Hybrid (biology), an offspring resulting from cross-breeding ** Hybrid grape, grape varieties produced by cross-breeding two ''Vitis'' species ** Hybridity, the property of a hybrid plant which is a union of two dif ...

between a cockatiel and a

galah The galah (; ''Eolophus roseicapilla''), also known as the pink and grey cockatoo or rose-breasted cockatoo, is the only species within genus ''Eolophus'' of the cockatoo family. Found throughout Australia, it is among the most common of the co ...

, another cockatoo species.

Description

The cockatiel's distinctive

crest Crest or CREST may refer to: Buildings *The Crest (Huntington, New York), a historic house in Suffolk County, New York *"The Crest", an alternate name for 63 Wall Street, in Manhattan, New York *Crest Castle (Château Du Crest), Jussy, Switzerla ...

expresses the animal's emotional state. 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. When the cockatiel is tired, the crest is seen positioned halfway upwards, with the tip of the crest usually curling upward. In contrast to most cockatoos, the cockatiel has long tail feathers roughly making up half of its total length. At , the cockatiel is the smallest of the cockatoos which are generally larger at between . 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 ears, often referred to as "cheddar cheeks". 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. Cockatiels are relatively vocal birds, the calls of the male being more varied than that of the female. Cockatiels can be taught to sing specific melodies, to the extent that some cockatiels have been demonstrated synchronizing their melodies with the songs of humans, and speak many words and phrases. They have also learned to imitate certain human or environmental sounds without being taught how to do so.

Sexual dimorphism

Most wild cockatiel chicks and juveniles look female, and are virtually indistinguishable from the time of hatching until their first

moulting In biology, moulting (British English), or molting (American English), also known as sloughing, shedding, or in many invertebrates, ecdysis, is the manner in which an animal routinely casts off a part of its body (often, but not always, an outer ...

. They display horizontal yellow stripes or bars on the

ventral Standard anatomical terms of location are used to unambiguously describe the anatomy of animals, including humans. The terms, typically derived from Latin or Greek language, Greek roots, describe something in its standard anatomical position. Th ...

surface of their tail feathers, yellow spots on the ventral surface of the primary flight feathers of their wings, a grey coloured crest and face, and a dull orange patch on each of their cheeks. However some modernday mutations are sexlinked and the male and female chicks are easily distinquishable as soon as their feathers come in. Adult cockatiels with common coloring (grey body with yellow head) are

sexually dimorphic Sexual dimorphism is the condition where the sexes of the same animal and/or plant species exhibit different morphological characteristics, particularly characteristics not directly involved in reproduction. The condition occurs in most ani ...

, though to a lesser degree than many other avian species. This is only evident after the first moulting, 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 grey 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 grey with a yellowish tint, and a less vibrant orange cheek patch. Additionally, the female commonly retains the horizontal barring on the underside of her tail feathers. The colour in cockatiels is derived from two

pigment A pigment is a colored material that is completely or nearly insoluble in water. In contrast, dyes are typically soluble, at least at some stage in their use. Generally dyes are often organic compounds whereas pigments are often inorganic compo ...

melanin Melanin (; from el, μέλας, melas, black, dark) is a broad term for a group of natural pigments found in most organisms. Eumelanin is produced through a multistage chemical process known as melanogenesis, where the oxidation of the amino ...

(which provides the grey colour in the feathers, eyes, beak, and feet), and

psittacofulvin Psittacofulvin pigments, sometimes called psittacins are responsible for the bright-red, orange, and yellow colours specific to parrots. In parrots, psittacofulvins are synthesized by a polyketide synthase enzyme that is expressed in growing feath ...

s (which provide the yellow colour on the face and tail and the orange colour of the cheek patch). The grey colour of the melanin overrides the yellow and orange of the psittacofulvins when both are present. The melanin content decreases in the face of the males as they mature, allowing the yellow and orange psittacofulvins 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 vocalisation of adult males is typically louder and more complex than that of females. But like most things this isn't a hard and fast rule.

Colour mutations

Worldwide there are currently 22 cockatiel colour

mutation In biology, a mutation is an alteration in the nucleic acid sequence of the genome of an organism, virus, or extrachromosomal DNA. Viral genomes contain either DNA or RNA. Mutations result from errors during DNA or viral replication, mi ...

s established in

aviculture Aviculture is the practice of keeping and breeding birds, especially of wild birds in captivity. Types There are various reasons that people get involved in aviculture. Some people breed birds to preserve a species. Some people breed parrots a ...

, of which eight are exclusive to Australia. Mutations in captivity have emerged in various colours, some quite different from those observed in nature. Wild cockatiels are grey with visible differences between males and females. Male grey cockatiels typically have yellow heads while the female has a grey head. Juveniles tend to look like females with pinker beaks. The pied mutation first appeared in California in 1949. This mutation is a blotch of colour on an otherwise solid-coloured bird. For example, this may appear as a grey blotch on a yellow cockatiel. Lutino colouration was first seen in 1958. These birds lack the grey of their wild counterparts and are white to soft yellow. This is a popular colour; due to inbreeding, these cockatiels often have a small bald patch behind their crests. The cinnamon mutation, first seen in the 1950s, is very similar in appearance to the grey; however, these birds have a warmer, browner colouring. Pearling was first seen in 1967. This is seen as a feather of one colour with a different coloured edge, such as grey feathers with yellow tips. This distinctive pattern is on a bird's wings or back. The albino colour mutation is a lack of pigment. These birds are white with red eyes. Fallow cockatiels first appeared sometime in the 1970s. This mutation shows as a bird with cinnamon colouring with yellow sections. Other mutations include emerald/olive, dominant and recessive silver, and mutations exclusive to Australia: Australian fallow, faded (west coast silver), dilute/pastel silver (east coast silver), silver spangle (edged dilute), platinum, suffused (Australian olive), and pewter. Other mutations, such as face altering mutations, include whiteface, pastelface, dominant yellow cheek, sex-linked yellow cheek, gold cheek, cream face, and the Australian yellow cheek. Cockatiel colour mutations can become even more complex as one bird can have multiple colour mutations. For example, a yellow lutino cockatiel may have pearling – white spots on its back and wings. This is a double mutation. An example of a quadruple mutation would be cinnamon cockatiel with yellowface colouring with pearling and pied markings. File:Female Pearl Cockatiel.jpg, Female pearl cockatiel File:Tiel kiss.png, Two different-coloured male cockatiels File:Daisy Flower Lutino Cockatiel.jpg, Female lutino cockatiel File:Eddie, a 1.5 year old male cockatiel.png, 1.5 year old male lutino cockatiel

Distribution and habitat

Nymphicus hollandicus -perching on wires -Australia-6a

Cockatiels are native to Australia, where they are found largely in

arid A region is arid when it severely lacks available water, to the extent of hindering or preventing the growth and development of plant and animal life. Regions with arid climates tend to lack vegetation and are called xeric or desertic. Most ar ...

semi-arid A semi-arid climate, semi-desert climate, or steppe climate is a dry climate sub-type. It is located on regions that receive precipitation below potential evapotranspiration, but not as low as a desert climate. There are different kinds of semi-ar ...

country but always close to water. Largely nomadic, the species will move to where food and water is available. They are typically seen in pairs or small flocks. Sometimes, hundreds will flock around a single body of water. Wild cockatiels typically eat seeds, particularly ''

Acacia ''Acacia'', commonly known as the wattles or acacias, is a large genus of shrubs and trees in the subfamily Mimosoideae of the pea family Fabaceae. Initially, it comprised a group of plant species native to Africa and Australasia. The genus na ...

'',

wheat Wheat is a grass widely cultivated for its seed, a cereal grain that is a worldwide staple food. The many species of wheat together make up the genus ''Triticum'' ; the most widely grown is common wheat (''T. aestivum''). The archaeologi ...

sunflower The common sunflower (''Helianthus annuus'') is a large annual forb of the genus ''Helianthus'' grown as a crop for its edible oily seeds. Apart from cooking oil production, it is also used as livestock forage (as a meal or a silage plant), as ...

and ''

Sorghum ''Sorghum'' () is a genus of about 25 species of flowering plants in the grass family (Poaceae). Some of these species are grown as cereals for human consumption and some in pastures for animals. One species is grown for grain, while many othe ...

''. 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 Australia Western Australia (commonly abbreviated as WA) is a state of Australia occupying the western percent of the land area of Australia excluding external territories. It is bounded by the Indian Ocean to the north and west, the Southern Ocean to th ...

n deserts, and

Cape York Peninsula Cape York Peninsula is a large peninsula located in Far North Queensland, Australia. It is the largest unspoiled wilderness in northern Australia.Mittermeier, R.E. et al. (2002). Wilderness: Earth’s last wild places. Mexico City: Agrupación ...

. They are the only cockatoo

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

which can sometimes reproduce in the end of their first year.

Breeding

Breeding is triggered by seasonal rainfall. Cockatiels nest in tree hollows near a source of fresh water, often in eucalyptus trees. The hen lays 4-7 eggs - one every other day, which she incubates for 17–23 days. The chicks fledge after 5 weeks.

Life span

The cockatiel's life span in captivity is generally given as 16 to 25 years, though it is sometimes given as short as 10 to 15 years, and there are reports of cockatiels living as long as 32 years, the oldest confirmed specimen reported being 36 years old. File:Nymphicus hollandicus MWNH 0584.JPG, Egg, Collection

Museum Wiesbaden The Museum Wiesbaden is a two-branch museum of art and natural history in the Hessian capital of Wiesbaden, Germany. It is one of the three Hessian State museums, in addition to the museums in Kassel and Darmstadt. History The foundation of ...

File:PictureofSnowy2.jpg, One-day-old cockatiel chick File:Young cockatiel.jpg, Young fledged cockatiel File:Bird-4years.jpg, 4.5-year-old male cockatiel

References

External links

*
Inte Onsman's MUTAVI Research & Advice Group

Cockatiels – National Cockatiel Society

Cockatiel Information Forum and Bulletin Board
– Talk Cockatiels
Videos, images and sounds
– Internet Bird Collection {{Taxonbar, from=Q514809 Calyptorhynchinae Endemic birds of Australia Domesticated birds Parrots of Oceania Talking birds Birds described in 1792 Articles containing video clips Taxa named by Robert Kerr (writer)