Cockatiels

The **cockatiel** (*Nymphicus hollandicus*), also known as **weiro bird**, or **quarrion**, is a small parrot that is a member of its own branch of the cockatoo family endemic to Australia. They are prized as household pets and companion parrots throughout the world and are relatively easy to breed. As a caged bird, cockatiels are second in popularity only to the budgerigar.

The cockatiel is the only member of the genus ***Nymphicus***. It was previously considered a crested parakeet 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 (cockatoo family). Cockatiels are native to Australia, favouring the Australian wetlands, scrublands, and bushlands.

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 Europeans to see the birds in their native habitat; the travellers 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 relationships were for a long time uncertain; it is now placed in a monotypic subfamily Nymphicinae, but was sometimes in the past classified among the Platycercinae, 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 12S rRNA sequence data places it among 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.

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 (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 between a cockatiel and a galah, another cockatoo species.

The cockatiel's distinctive erectile crest 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 30 to 33 cm (12 to 13 in), the cockatiel is the smallest of the cockatoos which are generally larger at between 30 and 60 cm (12 and 24 in).
Wild cockatiels, Australia
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 and speak many words and phrases. They have also learned to imitate certain human or environmental sounds without being taught how to do so.