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Eastern rosella

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Eastern rosella
P. e. diemenensis (male)
P. e. diemenensis (female)
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Psittaciformes
Family: Psittaculidae
Genus: Platycercus
Species:
P. eximius
Binomial name
Platycercus eximius
(Shaw, 1792)

The eastern rosella (Platycercus eximius) is native and endemic to south-eastern Australia. It was first introduced to New Zealand in cages, which then both intentionally released and accidentally escaped into the wild[2] and has been found establishing mainly in the North Island[3] (notably in the northern half of the island, Taranaki, Waikato and in the Hutt Valley) and in the hills around Dunedin in the South Island[4][5] since the early 20th century.[6]

Taxonomy

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P.eximius (Eastern Rosella) is located under the genus Platycercus and subgenus Violania along with other three species members: P.venustus (Northern Rosella), P.adscitus (Pale-headed Rosella) and P.icterotis (Western Rosella).[7]An early analysis of rosella phylogeny stated that the taxa of eastern rosella and pale-headed rosella are most closely related to each other compared to the other two rosella species.[8][9]Then, the hybrids of the two taxa have been recorded in northeastern New South Wales and southeastern Queensland, as both species have been recorded habituating in the same ecological area ranges, differ from the other two species [9] However, a mitochondrial study published in 2017 found that the eastern rosella was the earlier offshoot of the lineage that split into the pale-headed and northern rosellas and those non-sister taxa were hence able to hybridize.[8]

The three subspecies of eastern rosella are:[10]

  • P. e. eximius, which is mainly found in Victoria and southern New South Wales, Australia. The black feathers on the back have green margins, and its rump is pale green.
  • P. e. elecica, which is found in northeast New South Wales and southeast Queensland. For males, the black feathers on the back have golden-yellow margins, but greenish yellow in the female. For both sexes the rump is bluish-green. This subspecies is also called the golden-mantled rosella, often abbreviated to GMR.
  • P. e. diemenensis, mostly found in eastern Tasmania. White cheek patches are larger and the red on the head is darker.

Description

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The length of eastern rosella is 30 cm (12 in). Its cheeks are white, and it has a red colored head. The beak is white, and the irises are brown. Its upper breast is red, and its lower breast is yellow and fades to pale green over the abdomen. The black feathers on the back and shoulders have yellowish and greenish margins which gives the scalloped look that differs between the sexes and subspecies. Moreover, the wings and lateral tail feathers are bluish while the tail is dark green. Meanwhile, their legs are grey. For the females, it is the same with males which is duller in coloration and has an underwing stripe, but is not present in the adult male. The colour of their young is duller than the females and has an underwing stripe.[10]

Distribution

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The eastern rosella (Platycercus eximius) has become naturalised in New Zealand.[3] By the 1970s the population, probably originally from cage escapees, was strongly established throughout Auckland , Northland, and the far north, extending into west Waikato, as far south as Kawhia and Te Kuiti, and east to the Coromandel Peninsula. The species is also found in the Wellington-Hutt Valley Region, established in the 1960s from escaped cage birds, later colonising the foothills of the Tararua Range, to Eketahuna in the east, and Ōtaki in the west (range up to 1985).[11] There have been sightings in Newthe the Plymouth, Taupo, Gisborne, Tiritea, Banks Peninsula, Nelson area, and Stewart Island. The first occurrence of these parrots in New Zealand was about 1910 when a small shipment of eastern rosellas, as well as a few crimson rosellas (P. elegans), that had been refused entry into New Zealand by the Customs Department was released off Otago Heads by the ship that brought them, as she was returning to Sydney. The two species crossed, and by 1955 no pure crimson rosellas remained in the Dunedin area.[12] The population of rosellas in Dunedin has always remained low, partially due to them being trapped and sold as caged birds.

Habitat

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In New Zealand, the eastern rosella occupies along the edges or remnant patches in open woodland and forest areas, surrounding the shelter belts, gumlands, and orchards as well as cultivated exotic crops and town areas including gardens and golf courses. In Wellington, they also commonly inhabit open areas in cities or urban areas, as well as agricultural lands, which are the same preferred areas reported in both New Zealand and Australia.[13] [14]

Breeding and Nesting

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In Australia, eastern rosella usually breeds from August to January-February.[14] As eastern rosella is known as a cavity nester, they often build their nests mainly in the hollows of tree trunks, limbs, fallen logs or tree stumps, gateposts, and nest boxes. Occasionally, they also nest in other locations like wall cavities in buildings as well as rabbit burrows. Female eastern rosella will lay 5 to 6 eggs on average, at intervals of 1 to 3 days.[15] The eggs are usually laid in mid-November and mid-December [16] and soon after they are laid, they will be incubated for about 18 to 22 days, until they reach the fledging period, which happens about 30 to 33 days.[15] The fledging period usually begins in early December and ends in early February. [16] Usually, female eastern rosellas are said to lay two broods, with up to twelve offspring in every season.[17]

The characteristic of eastern rosella as a cavity nester contributes to its successful breeding, as they will minimize the amount of energy they spend while building their nest and thermoregulation activity. Cavity-nesting tends to result in a bigger clutch size and less predator threats.[18] Nevertheless, being an introduced species in New Zealand, the establishment of eastern rosella as a cavity nester affects the native cavity-nesting species as the distribution of these types of species depends on the availability of nest sites.[19] Presently, eastern rosella and other widely distributed cavity-nesting species in New Zealand such as common myna (Acridotheres tristis) appear to be a threat to native ones, due to expansion and geographical distribution.[20] In Northland of New Zealand, eastern rosella was outlined as the most distributed parrot, which results in a great competition in nest cavities and food resources with kākāriki species. Moreover, from the 1950s to 1960s, the reduction in the number of yellow-crowned parakeet (Cyanoramphus aurlceps) that habituated in some forests in the Northlands was said to be the result of the arrival of eastern rosella in that particular area which outcompete the nesting sites and food resources.[21]

When choosing a suitable location to breed, the presence of water sources close to the nesting site is one of the preferences for eastern rosella. Being near the water sources is advantageous for them not only to ease them to get access to water, but also to minimize their energy expenditure and time spent searching for it.[22] In addition, the eastern rosella prefers nesting in areas with presence of other accessible nests, as this increases the probability of finding the right breeding site.[22] The availability of several nests in the same area serves as alternatives, making it easier for them to rebuild a new nest if the old one is damaged or taken over.[23] Additionally, having a few unutilized nests around decreases the chance of the predator locating the right nest.[24] However, poor alternative nesting sites of eastern rosella like burrows, gate posts and tree stumps [13] which are usually located in lower areas, do expose themselves to flooding.[19] This affects the growth of their chicks and sometimes could lead to death.[13]



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  • The eastern rosella may be easily recognised by its distinctive back plumage.
    The eastern rosella may be easily recognised by its distinctive back plumage.
  • Juvenile P. e. diemenensis
    Juvenile P. e. diemenensis
  • Egg of Platycercus eximius - MHNT
    Egg of Platycercus eximius - MHNT
  • Eastern rosella chicks
    Eastern rosella chicks

References

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  1. ^ BirdLife International (2016). "Platycercus eximius". IUCN Red List of Threatened Species. 2016: e.T22685126A93059555. doi:10.2305/IUCN.UK.2016-3.RLTS.T22685126A93059555.en. Retrieved 12 November 2021.
  2. ^ Wright, D.; Clout, M. (2001). The eastern rosella (Platycercus eximius) in New Zealand. DOC science internal series 18. Department of Conservation, Wellington.
  3. ^ a b Falla, R.A.; Sibson, R.B.; Turbot, E.G. (1966). A Field guide to the birds of New Zealand. Collins. ISBN 0-00-212022-4.
  4. ^ "3. Cockatoos and rosellas –". Introduced land birds. Te Ara Encyclopedia of New Zealand.
  5. ^ Woon, J.A.; Powlesland, R.G.; Edkins, C. (2002). "Observations of the eastern rosella (Platycercus eximius) in the Wellington region" (PDF). Notornis. 49: 91–94.
  6. ^ Oliver, W.R.B. (1955). New Zealand birds (2nd ed.). Wellington.{{cite book}}: CS1 maint: location missing publisher (link)
  7. ^ Shipham, A., Schmidt, D. J., Joseph, L., & Hughes, J. M. (2017). A genomic approach reinforces a hypothesis of mitochondrial capture in eastern Australian rosellas. The Auk: Ornithological Advances, 134(1), 181-192.
  8. ^ a b Shipham A, Schmidt DJ, Joseph L, Hughes JM (2017). "A genomic approach reinforces a hypothesis of mitochondrial capture in eastern Australian rosellas". The Auk. 134 (1): 181–92. doi:10.1642/AUK-16-31.1. hdl:10072/338495.
  9. ^ a b Cannon, C.E. (1984). "Rosellas, Platycercus spp., and their hybrids in the eastern Queensland – New South Wales border region" (PDF). Australian Zoologist. 21: 175–83.
  10. ^ a b Forshaw, Joseph M. (2006). Parrots of the World; an Identification Guide. Illustrated by Frank Knight. Princeton University Press. ISBN 0-691-09251-6.
  11. ^ Robertson, H.A. (1985). Reader's Digest Complete Book of New Zealand Birds. ISBN 9780949819628. OCLC 610863778.
  12. ^ Oliver, W.R.B. (1955). New Zealand Birds (2nd ed.). Reed. OCLC 697764998.
  13. ^ a b c Higgins, P. J. (1999). ‘Handbook of Australian, New Zealand and Antarctic Birds. Vol. 4: Parrots to Dollarbird.’ (Oxford University Press: Melbourne.)
  14. ^ a b Wright, D.; Clout, M.N. (2001). The eastern rosella (Platycercus eximius) in New Zealand. Department of Conservation. pp. (5-27).
  15. ^ a b Higgins, P.J. (1999). Platycercus eximius eastern rosella in: Handbook of Australian,New Zealand and Antarctic Birds (4th ed.). Melbourne: Oxford University Press. pp. 341–356.
  16. ^ a b Wyndham, E.; Brereton, J. le Gay (1982). 'Ageing and sexing Eastern Rosellas'. Corella. pp. 89–91.
  17. ^ Brereton, J. le Gay. (1963). 'The life cycles of three Australian Parrots: some comparative and population aspects'. Living Bird. pp. 21–29.
  18. ^ Lack,D.(1954). "The Natural Regulation of Animal Numbers." (Clarendon Press: Oxford, UK.)
  19. ^ a b Nilsson, S. G. (1984). The evolution of nest-site selection among hole-nesting birds: the importance of nest predation and competition. Ornis Scandinavica 15, 167–175. doi:10.2307/3675958
  20. ^ Robertson, C. J. R., Hyvonen, P., Fraser, M. J., and Prichard, C. R. (2007). ''Atlas of Bird Distribution in New Zealand.'' (Ornithological Society of New Zealand: Wellington.)
  21. ^ Ogle, C.C. (1982). Wildlife and wildlife values in Northland. New Zealand Wildlife Service Fauna Survey Report 30. New Zealand Wildlife Service, Wellington.
  22. ^ a b Galbraith, J. A., Clout, M. N., & Hauber, M. E. (2014). Nest-site use by an introduced parrot in New Zealand. Emu-Austral Ornithology, 114(2), 97-105.
  23. ^ Rendell, W. B., and Robertson, R. J. (1994). Defense of extra nest-sites by a cavity nesting bird, the Tree Swallow (Tachycineta bicolor). Ardea 82, 273–285.
  24. ^ Martin, T. E. (1988). On the advantage of being different: nest predation and the coexistence of bird species. Proceedings of the National Academy of Sciences of the United States of America 85, 2196–2199. doi:10.1073/pnas.85.7.2196

Further reading

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Wikimedia Commons has media related to Platycercus eximius.
Wikispecies has information related to Platycercus eximius.
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