This species has an extremely small wild population (<30 mature individuals) and is now known to breed at only one site, where it appears to have undergone an extremely rapid recent decline. Reasons for this recent decline are unclear, though the species has suffered from previous loss, fragmentation and degradation of winter habitat, and changes to fire regime in the breeding habitat. Likely causes of the recent decline are an outbreak of Psittacine Beak and Feather Disease in 2014 and the effects of a ten-year drought on productivity of saltmarsh plants in the winter habitat that reduced the breeding condition of females. It is also likely that the lack of habitat burns in the preferred breeding habitat has reduced the availability and quality of preferred food plants. The species is therefore classified as Critically Endangered.

This species breeds only in south-western Tasmania, Australia. The current known breeding population is only found at one small site, at Melaleuca, but the historical distribution was more extensive and unsuccessful attempts were made to re-establish a population at Birch’s Inlet. Birds migrate to the mainland after breeding, sometimes stopping over on King Island, and overwintering at coastal sites in south-eastern South Australia and Victoria. Annual winter counts in Victoria, South Australia and Bass Strait from 1979 to 1990 varied between 67 and 122, with no significant change in numbers (Starks et al. 1992). Numbers recorded in mainland surveys have since declined, for example 48 birds recorded from 19 sites in 2007 (Saunders 2008). The overall population, which was estimated to number around 150 individuals in 2005 (M. Holdsworth in litt. 2005), has since undergone a rapid decline (confirmed by data from both breeding and wintering sites): surveys in early 2010 found fewer than 50 birds at Melaleuca and no birds at any other historical breeding areas (Sims 2010). The wild population was therefore estimated to contain fewer than 50 individuals in 2010, and extinction in the wild has been predicted to take place within 3-5 years (Sims 2010). More recently, the total post-breeding wild population at Melaleuca was only 35, including 18 juveniles (M. Holdsworth in litt. 2016). Based on mean annual survival estimates (Holdsworth et al. 2011) the return of mature individuals in 2016/17 was predicted to be 20-25. Low breeding participation of females appears to be a limiting factor in some years, with some females not breeding every year (Sims 2010). Only 12 and 13 young are known to have fledged at Melaleuca in 2008/09 and 2009/10 respectively, and urgent action was taken in 2010/11 to secure the captive population by the collection of 21 of 27 young as founders in that year (Garnett et al. 2011). In recent years the output of fledglings has recovered somewhat with an average of 25/year (14-39/year). The captive insurance population has expanded in recent years and by April 2016 consisted of about 325 individuals held at ten facilities under a cooperative breeding programme and is considered to be secure (A. Everaardt in litt. 2016). Re-establishment of the Orange-bellied Parrot at Birch's Inlet was attempted during the period 1999-2009 with a total of 410 captive-bred birds being released, which produced 71 wild-bred fledglings. However, the reintroduction attempt failed because mean annual adult survival of released birds was 0.30 - half that of wild birds (0.65) - and the low fertility rate of 0.55 mimics the low fertility of the captive population (0.57), which is significantly less than in wild birds (0.86). Breeding output at this site was further limited by nest competition and depredation. 

Surveys in early 2010 found fewer than 50 birds at Melaleuca and found no birds at any other historical breeding areas. The wild population was therefore estimated to contain fewer than 50 individuals and mature individuals in 2010. The total wild population at the end of the 2015/16 season was only 35 (M. Holdsworth in litt. 2016) and has decreased to 14 in 2017. The sex ratio is highly skewed (12 males and 2 females) (D. Stojanovic in litt. 2017). Captive breeding programmes have been carried out since 1986 to restock the wild population, with more than 300 individuals in different breeding centres in Australia and Tasmania (BirdLife Australia in litt. 2016).

The Orange-bellied Parrot breeds in a mosaic of eucalypt forest and rainforest bordering extensive moorland plains. Nesting occurs in tree hollows and the species feeds on the seeds of a range of grasses and sedges in moorlands. There is some evidence that early in the breeding season birds prefer to forage in areas burnt seven to 15 years earlier, whilst later in the breeding season they prefer areas burnt three to five years earlier (Garnett et al. 2011). After breeding, Orange-bellied Parrots migrate to saltmarshes, dunes, beaches, pastures and shrublands close to the coast (<5 km), where there they feed on the ground or in low vegetation, almost exclusively on seeds, mainly of salt-tolerant coastal and saltmarsh plants (Loyn et al. 1986, Garnett et al. 2011).

The primary reason for the species's rarity is thought to be its specialist habitat requirements, and fragmentation and degradation of winter habitat by grazing, agriculture and urban and industrial development. Changes have also occurred in the breeding habitat, where there has been reduction of fire, which would normally produce favourable habitat structure for the species. Up until the 1990s, fire was regularly used by small-scale tin miners to reduce vegetation cover to aid mining and protect assets, coincidentally producing high quality foraging habitat for the species. Management of the area is now subject to stricter use of fire by the land manager and due to a combination of lack of resources and risk aversion, habitat management burns have rarely been implemented. This has resulted in a gradual decline in the habitat quality for the species. Disease is an important threat to the tiny population. An outbreak of Psittacine Beak and Feather Disease (PBFD) in 2015 infected 19 out of 26 wild Orange-bellied Parrot nestlings tested (Anon. 2015). One adult also tested positive for the disease. This contributed to a decline in the wild population from 35 to 23 mature individuals in 2016. Competition with introduced seed-eating finches may have affected winter food availability, while some former breeding habitat may have been vacated because of a change in the fire regime and competition with introduced Common Starlings Sturnus vulgaris, which fill nest-hollows with nesting material, rendering them unsuitable. The introduced Sugar Glider Petaurus breviceps is also implicated as a predator of incubating females, eggs and nestlings during the Birch's Inlet release and is a known threat to other species including the Swift Parrot (Stojanovic et al. 2014). Sugar Gliders are absent from Melaleuca and therefore may have had an influence on the contraction of the breeding range. Deaths from random events, such as predation by foxes and cats, or disease, are significant threats to such a tiny population. Ongoing degradation of remaining saltmarsh habitat on the mainland is a significant threat (C. Tzaros and M.A. Weston in litt. 2003). A ten-year drought reduced productivity of saltmarsh plants in the winter habitat, reducing the breeding condition of females. Windfarm developments may kill about one bird per year (Smales et al. 2005). Due to the low population size, the species is highly susceptible to genetic Allee effects, which might lead to further population reductions (Crates et al. 2017).

Conservation and Research Actions Underway
CITES Appendix I. A recovery team was established in 1980, a wide range of research projects are ongoing, and awareness-raising and education programmes are conducted. Much feeding habitat in Tasmania (including King Island), Victoria and South Australia has been reserved or is managed. Breeding, migration and winter counts are made annually, and almost 100% of the wild population is colour-banded. A captive breeding programme has been established and the population of about 350 birds is held at 10 institutions under a cooperative captive breeding effort. The captive population is predominantly derived from six founders collected in the 1980s (perhaps leading to low egg fertility as a result of inbreeding depression) but more recently has been bolstered by the inclusion of 21 new founders collected in 2010. Captive-bred birds that have been released have apparently migrated successfully between their breeding and wintering grounds (Loyn et al. 2005, Anon. 2014), but few birds released on the breeding grounds return in the following breeding season (Troy and Gales 2016), suggesting that most released birds fail to migrate or survive to the following year. As the population is severely male biased (six males per one female), a higher proportion of females is released in spring to correct the sex ratio imbalance (Stojanovic et al. 2017). The survival rate and reproductive success of captive-reared birds are far lower than for wild birds (Holdsworth 2006, Holdsworth et al. 2011, Stojanovic et al. 2017). Moreover, the plumage of captive-bred birds is in poorer condition, which might prove to be energetically costly, especially during migration (Stojanovic et al. 2017). Of  53 captive birds released in 2014 and 2015, just six survived to return to Melaleuca. An additional 27 captive bred individuals were released at Melaleuca in 2015. The behaviour of released birds has been monitored, and differs in many respects from those of wild parrots (Penrose 2016).

Conservation and Research Actions Proposed
Survey all saltmarsh in wintering range using satellite imagery. Monitor genetic heterozygosity. Model breeding and feeding habitat to assess availability. Re-establish saltmarsh in areas where it is likely to benefit the species. Monitor and manage Psittacine Circoviral Disease in the captive population. Control human disturbance at Victorian sites and Melaleuca, Tasmania. Control predators at mainland sites. Control feral cats at King Island site. Create new winter habitats. Protect key wintering sites in South Australia. Develop and implement a media strategy. Continue to manage wild breeding population, but revise and reduce supplementary feeding. Capture enough wild parrots to maximise genetic variability in captive population and maintain a healthy, genetically viable, captive population, increasing it to 400 individuals (Garnett et al. 2011, Stojanovic et al. 2017). Increase the number of captive-bred birds released into the wild. Carry out an active fire management program and protection of nests from competitors and predators.