Australian Ringneck Parrot/Parakeet Barnardius (zonarius) barnardi

Previously two species were recognised: Port Lincoln (Barnardius zonarius) and Mallee Ringneck (Barnardius barnardi). Since these interbreed where ranges overlap, they are now one species called the Australian Ringneck, with 4 subspecies shown below. (Related to the Rosellas, they were previously put in that genus of Platycercus by some.)

Mallee Ringneck Parrot/ Barnard's Parakeet/Australian Ringneck Barnardius (zonarius) barnardi

Mallee Ringneck Parrot
Mallee Ringneck Parrot
Mallee Ringneck
Mallee Ringneck Parrots, also known as Mallee Parrots or Barnard's Parakeets, are native to south-eastern Australia.
Mallee Ringneck Parrot
Barnard Parakeet
Mallee Parrot
Similar to other Australian Ringnecks/Barnardius parrots below, the Mallee can be distinguished by its red brow (without black head). Females have slightly duller plumage than males.
Mallee Ringneck Parrot
Barnard Parakeet
Mallee Parrot

Conclurry Parrot/Australian Ringneck Barnardius zonarius (prev. barnardius) macgillivrayi

Conclurry Ringneck Parrot
Conclurry Ringneck Parrot
Conclurry Ringneck Parrot
The Conclurry Parrot is similar to the Mallee Ringneck but has paler plumage, more yellow on its belly and no red brow. Its range is north-western Queensland and Northern Territory.
Conclurry Ringneck Parrot
Conclurry Ringneck Parrot
Conclurry Ringneck Parrot
The male has brighter coloured plumage than the female.
Conclurry Ringneck Parrot
Conclurry Ringneck Parrot
Conclurry Ringneck Parrot
The broad blue-green tail edged in white betrays the relationship to the Rosellas.

Port Lincoln Parrot/Australian Ringneck Barnardius zonarius zonarius

Port Lincoln Parrot
Port Lincoln Parrot
Port Lincoln Parrot
The Port Lincoln Parrot has a black head with blue cheeks/chin and the pale yellow collar of Australian Ringnecks.
Port Lincoln Parrot
Port Lincoln Parrot
Port Lincoln Parrot
Its range is central, south-central and east of Western Australia.
Port Lincoln Parrot
Port Lincoln Parrot
Port Lincoln Parrot
Its range is central and south-central Australia and east of Western Australia.

Twenty-eight Parrot/Australian Ringneck Barnardius zonarius semitorquatus

Twenty-eight Ringneck Parrot
Twenty-eight Parrot
28 Parrot
The Twenty-eight Parrot, also known as the Yellow-collared Parrot, is similar to the Port Lincoln (of which it used to be thought a subspecies) but has a red band above the beak and has a green belly rather than yellow. The bird's call is said to sound like "twenty-eight". Its range is south-west of Western Australia.