Justification of Red List Category
One was recorded in 2005 in the Pilbara region, and a dead immature bird was found in Diamantina National Park, Queensland in 2006. Sometime prior to 2013, a population was located in southwestern Queensland and an unknown number (suspected to be small) of individuals were detected every month during a survey between August 2013 and January 2016 (Murphy 2016). This population is thought to be part of a larger regional-scale extant population (Night Parrot Recovery Team, pers. comm. 2016 in TSSC 2016). The species is categorised as Endangered based on a very small population size with no evidence of recent decline.
The size of the currently known population has not been estimated, but it is assumed here and in Garnett et al. (2011) that the number of mature individuals is in the band 50-249, but may prove to be larger.
The quality of the species's habitat is suspected to be in decline owing to a combination of pervasive threats.
Pezoporus occidentalis is endemic to Australia, where historic records and observations are scanty and anecdotal with few substantiated records since 1935. There are accepted historical records from remote arid and semi-arid inland regions of Western Australia, Northern Territory, South Australia and Queensland (Higgins, 1999). It is possible that the night parrot may continue to occur throughout much of this range (Garnett et al. 2011). Despite numerous unverified sightings, several dedicated searches and public campaigns there have been only two areas (western Queensland and the Pilbara in Western Australia) where reliable records (including near Boulia in 1990, in the Pilbara in 2005 [Davis and Metcalf 2008] and in Diamantina National Park in 2006 [Cupitt and Cupitt 2008, McDougall et al. 2009]) indicate that populations may persist (Night Parrot Recovery Team pers comm. 2016 in TSSC 2016). Sometime prior to 2013, a population was located in southwestern Queensland by naturalist John Young. An unknown number (suspected to be small) of individuals were detected every month during a survey between August 2013 and June 2016 (S. Murphy in litt. 2016). This population is thought to be part of a larger regional-scale extant population (Night Parrot Recovery Team pers. comm. 2016 in TSSC 2016). The location of the main occupied area, named the Pullen Pullen Nature Reserve, owned and managed by conservation charity Bush Heritage Australia, is adjacent to Diamantina National Park (TSSC 2016).
The variation between reports and observations may be due to actual variation in the species’ ecology across its range, or due to erroneous assumptions and/or from spurious observations. For example Higgins (1999) reported that the species may be nomadic, have very large home ranges, be sedentary under suitable conditions, be absent during dry seasons with little seed, be present when seed is plentiful, and move between samphire and spinifex according to seed availability but acknowledges both the lack of evidence to support these views and that the observations are inconclusive. Systematic acoustic monitoring (Murphy 2015, 2016) has shown that night parrots in southwestern Queensland regularly roosted in the same location despite exceptionally dry conditions when no Triodia (Spinifex) seed was available, corroborating the report that birds may remain sedentary under suitable conditions in some parts of the range. Similarly, night parrots were recorded drinking water in northeastern South Australia and northwestern Western Australia (Higgins 1999). GPS tag data of a single male in May 2016 revealed that this bird did visit free standing water, although preliminary biophysical modelling suggests that they may normally only need to do so during hot periods (S. Murphy in litt. 2016). At other times, Night Parrots are likely to satisfy water requirements from their diet, which may include succulent plants, such as Sclerolaena spp. Most habitat records are of Triodia (Spinifex) grasslands and/or chenopod shrublands (Garnett et. al. 2011) in the arid and semi-arid zones, and Higgins (1999) listed Astrebla spp. (Mitchell grass), shrubby samphire and chenopod associations, scattered trees and shrubs, Acacia aneura (Mulga) woodland, treeless areas and bare gibber as associated with sightings of the species. S. Murphy (pers. comm. in TSSC 2016) recorded a similar range of habitats used or traversed by individuals in southwestern Queensland: Cretaceous sandstone, claystone, and siltstone residuals; either dominated by Triodia longiceps on slopes and margins of duricrust plateaus or with Sclerolaena spp., Maireana spp. (Saltbush spp.), Ptilotus spp. (Mulla Mulla spp.), and small areas of T. longiceps; with occasional watercourses with Acacia cambagei (stinking gidgee). A GPS tagged bird in an exceptionally wet period in May 2016 spent considerable time feeding in highly productive alluvial habitats, dominated by a diverse suite of annual or short-lived perennial herbs, forbs and grasses (S. Murphy in litt. 2016). Such areas overlap considerably with high value beef cattle grazing areas. Photographs (Murphy 2015, 2016) of roost and suspected foraging locations in these habitats show isolated Spinifex and chenopod clumps on bare gibber, and scattered Sclerolaena plants growing in the margins of an erosion runnel on bare gibber. Roosting and nesting sites are consistently reported as within clumps of dense vegetation, primarily old and large Spinifex clumps, but sometimes other vegetation types (Higgins 1999, Murphy 2015). The habitat of the southwestern Queensland population is naturally fragmented, and is unlikely to promote fire behaviour that results in most habitat in this area being burned by one fire event (Murphy 2015, pers. comm. 2016 in TSSC 2016). At one location in April 2015 in southwestern Queensland, Murphy (2016) regularly detected a radio-tagged night parrot flying 7.2 km from its daytime roost, which was 13.5 km from the point of capture. The GPS tagged bird in 2016 made similar sized movements away from the roost area; mean minimum cumulative distance moved per night was 29.9 km (s.d. = 9.6 km; max. = 41.18 km; min. = 17.82 km). Nightly mean minimum convex polygon area was 783 ha (s.d. = 605 ha; max. = 1821 ha; min. = 305 ha). The total minimum convex polygon area for all GPS points over 5 nights was 3,344 ha (S. Murphy in litt. 2016).
The causes of the assumed decline of the species “....are essentially guesswork” (Garnett et al. 2011). Blyth (1996) proposed a list of threats considered realistic in the absence of direct evidence. Threats to the species are likely to vary across its range and might include predation by feral cats and foxes; soil disturbance, erosion and loss caused by herbivores (including livestock and over-abundant native and feral herbivores); degradation of habitat around water points by herbivores; competition for food by herbivores; fire; psittacine beak and feather disease, avian pox, and other diseases; illegal collection of birds or eggs; disturbance from bird watching activities; fences; and reduction in water availability through over-use of waterholes by camels and reduced waterhole maintenance (TSSC 2016). Biophysical modelling suggests that predicted temperature increases under various climate change scenarios would increase night parrots’ dependence on free-standing water dramatically (S. Murphy in litt. 2016). Thus, climate change, interacting with the spatial configuration of water points and habitats, and the concentration of feral predators at water points, may become a serious future threat.
Conservation Actions Underway
CITES Appendix I. The recent discovery of a small population in 2015 has led to an intensive conservation and research programme, directed towards the conservation actions proposed below.
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.
Text account compilers
Butchart, S., Bird, J., Garnett, S., McClellan, R., Benstead, P., Symes, A.
Metcalf, B., Bamford, M.J., Murphy, S., Burbidge, A.H., Joseph, L.
BirdLife International (2019) Species factsheet: Pezoporus occidentalis. Downloaded from http://www.birdlife.org on 19/10/2019. Recommended citation for factsheets for more than one species: BirdLife International (2019) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 19/10/2019.