About Platycercus eximius (Shaw, 1792)
The eastern rosella (Platycercus eximius) measures 30 cm (12 in) in length. It has a red head, white cheeks, a white beak, and brown irises. Its upper breast is red, while the lower breast is yellow, fading to pale green across the abdomen. Black feathers on the back and shoulders have yellowish and greenish margins that create a scalloped appearance, which varies between sexes and subspecies. The wings and lateral tail feathers are bluish, the central tail is dark green, and the legs are grey. Females have duller coloration than males and possess an underwing stripe that is absent in adult males. Juveniles are duller than females and also have an underwing stripe.
The eastern rosella has become naturalized in New Zealand. Its introduction dates to around 1910, when a small shipment of eastern rosellas and a few crimson rosellas (P. elegans) was denied entry by New Zealand Customs. The ship released the birds off Otago Heads while returning to Sydney; approximately 12 additional birds escaped in Dunedin after their cages were damaged in a gale. By the 1970s, eastern rosellas were well-established across Auckland, Northland, and the far north of the North Island, extending into western Waikato as far south as Kawhia and Te Kūiti, and east to the Coromandel Peninsula. The species was also present in the Wellington-Hutt Valley Region, and by 1985 it had begun colonizing the foothills of the Tararua Range, extending east to Eketāhuna and west to Ōtaki. Sightings have also been reported from New Plymouth, Taupō, Gisborne, Tiritea, Banks Peninsula, the Nelson area, and Stewart Island. In the South Island's Otago region, the eastern rosella population has remained relatively small, in contrast to the widely distributed North Island populations that currently cover most of the island. The New Zealand meta-population of eastern rosella originated from three main establishment sites: Dunedin, Auckland, and Wellington.
In Otago, eastern rosellas were widespread across Dunedin by the 1930s, and were sighted throughout Otago between the 1940s and 1950s. From 1950 to the 1970s, sightings in Otago declined and the population was recorded to be decreasing. This population drop was attributed to strychnine-grain poisoning targeting rabbits, as well as human trapping of wild birds for aviary collections. Since the 1980s, increased sightings of the species indicate the eastern rosella population around Dunedin has recovered.
In Auckland, eastern rosellas were mostly spread across mid to upper Northland in the 1960s. By the 1970s, the species had spread into Waikato, then later into Coromandel, the Bay of Plenty, and Taranaki. Records of eastern rosellas in mid-Coromandel and Waiheke Island from 1975-1976 suggest the species spread to the Coromandel Peninsula from Waikato. During early expansion into Taranaki, the species was more commonly recorded in Waikato than Manawatū, indicating the Taranaki eastern rosella population expanded southward from Auckland. Recent observations confirm the species is continuously present across western North Island.
Population growth of eastern rosellas in Wellington allowed further spread into northern Wellington, Manawatū, and Waitapa, confirmed by their establishment and regular sightings in these areas. No eastern rosellas have been sighted on Kapiti or Mana Islands. A wild breeding population exists around Waikanae, with breeding sites located in bush areas near the beach.
Eastern rosellas generally prefer to live in lowland areas. In New Zealand, they occupy edges or remnant patches of open woodland and forest, around shelter belts, former gumlands, and orchards. They are also frequently seen in areas with cultivated exotic crops and in urban town areas. In more urban settings, the birds inhabit well-maintained lawns, such as those in gardens and golf courses. Across both Australia and New Zealand, eastern rosellas favour open areas and agricultural lands.
