Tuesday, 26 June 2012

parrots

Justification  After no confirmed records since 1990, despite several dedicated searches and publicity campaigns, this species was rediscovered in 2005 in the Pilbara region of Western Australia, and a dead juvenile bird was found in Diamantina National Park, Queensland in 2006. It may occur at low density elsewhere in its former range, because it is easily overlooked. It is likely to have declined as a result of a number of threats, and the remaining population may be very small and possibly subject to extreme fluctuations. Following the 2005 and 2006 records, an expert committee concluded that given the spread of sightings it was not tenable to retain an extremely small population estimate, and the species has therefore been downlisted to Endangered.
Taxonomic source(s)  Christidis, L.; Boles, W. E. 1994. The taxonomy and species of birds of Australia and its territories. Royal Australasian Ornithologists' Union, Melbourne., Christidis, L.; Boles, W. E. 2008. Systematics and taxonomy of Australian birds. CSIRO Publishing, Collingwood, Australia., Sibley, C. G.; Monroe, B. L. 1990. Distribution and taxonomy of birds of the world. Yale University Press, New Haven, USA.
Synonym(s)  Geopsittacus occidentalis Sibley and Monroe (1990, 1993), Geopsittacus occidentalis occidentalis Sibley and Monroe (1990, 1993)




Identification  22-25 cm. Short-tailed, dumpy parrot. Sexes alike. Adult predominantly green, grading to yellow underparts, with extensive fine black markings. Mainly dark grey upperwing with narrow, pale yellow wing-bar. Grey-green underwing with broad wing-bar. Juvenile probably similar but duller. Similar spp. Distinguished from Budgerigar Melopsittacus undulatus by larger size, shorter tail, terrestrial nature and furtive nocturnal habits - but note that quite a few records of Night Parrots are from the day time, especially if flushed. Superficially similar Ground Parrot Pezoporuswallicus has longer tail and different range and habitat. Voice Said to have low, two-note or drawn-out whistle, audible at a distance; and a frog-like croak.

Distribution and population  Pezoporus occidentalis is endemic to Australia, where historical records are spread throughout the arid and semi-arid zones. There were comparatively few confirmed records from the 20th century. At least five dedicated searches and two broad-scale publicity campaigns in the 1990s failed to confirm the existence of any population, with only one authenticated record from near Boulia, north-western Queensland, in 1990. However, three birds were then reported at Minga Qwirriawirrie Well near the Fortescue Marshes in the Pilbara region of Western Australia in April 2005 (Davis and Metcalf 2008). Subsequent searches in 2005 and 2006 failed to relocate the species, but this may have been because there had been recent rain, and so birds were not concentrating at the waterhole (M. J. Bamford and B. M. Metcalf in litt. 2005). There were three possible sightings at two sites 145 km apart in the East Pilbara in 2010 (Ramsay 2010). A dead bird was found by Queensland Park and Wildlife Service Rangers in Diamantina National Park, Queensland in November 2006, less than 200 km from the1990 record, having apparently collided with a fence some weeks before (Birds Australia in litt. 2007, McDougall et al. 2009). It was positively identified by Queensland Museum and appeared to be an immature, implying a breeding event in the two years prior to September 2006 (McDougall et al. 2009). Flood rains in the Channel Country have prevented access to the area for follow-up surveys (Birds Australia in litt. 2007). It seems quite likely that this cryptic species occurs at a low density elsewhere in its former range as there have been unverified sight records from inland regions of all mainland states and the Northern Territory. However, there has almost certainly been a historical decline in abundance given the sharp decline in reporting since the 1880s, most likely as a result of predation by non-native mammals.




Population justification  Its remaining population is assumed to be very small, and was formerly precautionarily estimated to number fewer than 50 mature individuals based on the paucity of records. In 2010 an expert committee re-assessed this as untenable, given records from Western Australia in 2005 and Queensland in 2006, and estimated that there might be 50-250 birds in total (Garnett et al. 2011). The number of mature individuals is therefore placed in the band 50-249, but may prove to be larger. Trend justification  The population is suspected to be in decline owing to a combination of threats, including predation by alien invasive predators. 

Ecology 
Most specimens have been obtained from hummock grasslands Triodia-Plechtrachne or chenopod shrublands. It may persist in chenopod shrublands during dry years, moving into grassland after there is sufficient rain to set seed. The 1990 specimen and associ­ated reports were in Astrebla Mitchell grassland with scattered chenopods (Garnett et al. 1993, Boles et al. 1994), the 2006 specimen in sparse shrubland of gidgee Acacia cambagei, crimson turkey bush Eremophila latrobei and blunt-leaf cassia Senna artemisioides var. helmsii (McDougall et al. 2009) and there have been unconfirmed reports from mallee shrubland and in openEucalyptus woodland with an understorey of grasses (Menkhorst and Isles 1981, Garnett et al. 1993). The 2005 record involved birds drinking at a water hole which may have been drawn from their typical habitat to drink (M. J. Bamford and B. M. Metcalf in litt. 2005). It has been suggested that the species has a similar metabolism to rodents as it is active at night. This behaviour may help it retain water, most of which is obtained through its diet. Therefore, drinking may only occur in dry circumstances making the species difficult to locate in wet years (M. J. Bamford and B. M. Metcalf in litt. 2005). The two nests recorded have both been at the end of tunnels into dense vegetation and contained three-six eggs or young (Higgins 1999).




Threats  
The sharp decline in reporting after the 1880s suggests a historical decline in abundance. One early account suggests the decline at Innaminka and Alice Springs coincided with the arrival of feral cats. Similarly ‘many were brought in by cats at Alice Springs Telegraph Station’ in 1892 (Ashby 1924, in Garnett et al. 2011). Current threats are extrapolated from their presumed effects on medium-sized, arid-zone mammals, and include predation by feral cats and foxes Vulpes vulpes, altered fire regimes, competition for food, degradation of habitat near water by stock or rabbits Oryctolagus cuniculus, and reduced availability of water as a result of over-use by feral camels Camelus dromedarius.


Conservation measures underway  Conservation Actions Underway
CITES Appendix I. Appeals for information leading to the rediscovery of the species have received much publicity in arid Australia, especially in the Northern Territory and Western Australia. A National Night Parrot Network has been formed in direct response to the Diamantina specimen, to assist with information exchange and to encourage action by relevant organisations. Recent and ongoing searches in the Pilbara have concentrated on developing methods to find birds. A GIS analysis of existing records has been commenced with the aim of identifying ways to focus search efforts spatially and temporally.

Conservation Actions Proposed
Develop alternative detection techniques, particularly the use of a national team of dogs. Complete the current GIS analysis of recent and historic records against habitat to derive a population estimate for the species and identify priority areas to conduct searches. Develop captive-breeding and release techniques using Pezoporus w. wallicus. Encourage individuals or voluntary organisations to follow up any plausible reports providing appropriate logistic support. Develop a contingency plan for any site where birds are found, including a strategy for handling publicity, initiation of ecological studies, capture of birds to establish captive population, and initiation of fire management and predator control. 

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