Justification of Red List Category
This species is listed as Critically Endangered because population modelling predicts an extremely rapid decline owing to nest predation by the introduced Sugar Glider Petaurus breviceps in its Tasmanian breeding range. Habitat loss and alteration are also thought to be contributing to declines.
Garnett et al. (2011) estimate that the current population probably contains around 2,000 mature individuals and is declining. It is placed in the band 1,000-2,499 mature individuals.
A population viability analysis model predicted that the population will decline by an average of 87% (79-95%) over three generations (12-18 years) (Heinsohn et al. 2015). The most likely scenario predicts a population decrease by 94.7% in three generations due to predation by Sugar Gliders Petaurus breviceps. The models represent a conservative, best-case scenario - other likely causes of mortality such as habitat loss and collisions with man-made structures were not included. Predation by Sugar Gliders is likely to be so severe that even successful breeding on offshore islands free of the predator will be insufficient to prevent an overall population decline.
This species breeds in Tasmania, Australia, mostly along the south-eastern coast from St Helen's to Southport with a small breeding population in the north near Deloraine. After breeding, birds disperse throughout Tasmania before migrating north to mainland Australia. In most years, a large portion of the population winters in central Victoria, with a smaller number of birds wintering further afield (D. Saunders in litt. 2007). However during periods of extreme drought in central Victoria, Swift Parrots undertake large-scale movements (up to 1,000 km) to drought refuge habitats in wetter coastal areas of New South Wales (D. Saunders in litt. 2007). Small flocks are recorded in Queensland and the Australian Capital Territory on a regular basis (D. Saunders in litt. 2007). The range in South Australia appears to have contracted, with only irregular recent records of small flocks or individual birds from the south-east of the state. Population size and trends are poorly known.
In 1987-1988, the breeding population was estimated at 5,000 birds, including 1,320 breeding pairs, and in 1995-1996, at 940 breeding pairs (Brereton 1996). Annual surveys across the non-breeding range fluctuate depending on the distribution of the birds across the landscape and flock sizes (Garnett et al. 2011). In 2010 mainland surveys recorded 2,158 birds, including immatures, the highest count for many years (C. Tzaros and D. Ingwersen in litt. 2010). Garnett et al. (2011) estimate that the population probably contains around 2,000 mature individuals and is declining, however a population viability analysis model predicted that the population will decline by an average of 87% (79-95%) over three generations (12-18 years) (Heinsohn et al. 2015).
When breeding, it is almost always associated with its main food source, flowering Tasmanian blue gum Eucalyptus globulus. Flowering may be sufficient to support breeding in only three years out of every 10. In poor years, swamp (black) Gum E. ovata is used as food source (Brereton et al. 2004). Overall, the availability and flowering of the feed trees can severely affect the availability of breeding habitat (Tzaros et al. 2009). Most breeding birds are found in remnant forest patches of less than 0.01 km2. They nest in hollows of both live and dead eucalypt trees (D. Saunders in litt. 2007). The most common tree species used for nesting are stringybark E. obliqua, white peppermint E. pulchella and Tasmanian blue gum E. globulus, white gum E. viminalis, gum-topped stringybark E. delegatensis and dead stags (D. Saunders in litt. 2007). Several pairs often nest in close proximity, in the same or neighbouring trees. On the mainland, it occurs in eucalypt forest and woodlands, mainly box-ironbark habitats on the inland slopes of the Great Dividing Range and in coastal forests. Critical food resources occur within this habitat, principally nectar from prolific flowering species such as red ironbark E. tricarpa, grey box E. microcarpa, yellow gum E. leucoxylon and mugga ironbark E. sideroxylon on the western slopes, and Swamp Mahogany E. robusta and spotted gum Corymbia maculata in coastal areas. Lerp (sugary secretions from sap sucking insects on leaves; D. Saunders in litt. 2007) is also a favoured food source and is occasionally preffered over blossom, even when abundant blossom is available where birds are present (M. Roderick, D. Ingwersen pers. obs.). During the winter the birds are semi-nomadic and visit a network of traditional sites in reaction to flowering events and lerp availability (Kennedy and Tzaros 2005). Their wintering distribution varies greatly between years, depending on climatic conditions and the resulting food availability (Saunders and Heinsohn 2008). However it will also repeatedly use the same sites between years and often remain in winter foraging habitats for extended periods within a season (D. Saunders in litt. 2007). In some years, urban landscapes containing indigenous or non-local flowering eucalypts are also readily used (C. Tzaros in litt. 2003). The importance of larger trees as a food source has been shown in this species's breeding range (Brereton et al. 2004) and wintering range (Kennedy and Tzaros 2005), as such trees tend to offer a more reliable and abundant source of nectar. Individuals can travel up to 5,000 kilometres between their mainland wintering grounds and their Tasmanian breeding sites, making theirs the longest migration undertaken by any parrot in the world (Tzaros et al. 2009).
Nest predation by Sugar Gliders Petaurus breviceps introduced to Tasmania poses a severe threat (Stojanovic et al. 2014) and is estimated to cause severe declines over the next three generations (Heinsohn et al. 2015). Surveys revealed that Sugar Gliders predated nests and the probability of a nest surviving the 60-day nesting period when Sugar Gliders were present was 0.17 (Stojanovic et al. 2014). On mainland Tasmania almost 79% nests were predated and 65% of adult females were killed by Sugar Gliders. Predation was most severe in locations with low forest cover. Owing to the fact that Swift Parrot breeding distribution varies widely between years the extent of nest predation is also expected to vary annually depending on the distribution of Sugar Gliders and forest cover. Sugar Gliders have not been reported from Bruny Island, a Swift Parrot breeding site.
Habitat loss and alteration within breeding and drought refuge habitats remains a key threat. In Tasmania, breeding habitat is significantly reduced and fragmented through clearance of E. globulus for agriculture, residential development, plantation timber, sawlog production and clear-felling for woodchips. In 2017, a large area of key nesting habitat has been logged for timber extraction (D. Stojanovic in litt. 2017). Over 50% of the original grassy E. globulus forest in Tasmania has been cleared (Brereton et al. 2004). Selective logging has resulted in the removal of larger trees from the remaining forest patches. Such patches are typically unfenced and exhibit poor regeneration (Brereton et al. 2004). Competition for remaining nest-sites with Common Starlings Sturnus vulgaris could be a problem along forest edges. Even with protection of remaining habitat (80% private land), maintenance and recovery may be limited by the dependence of breeding on an irregular nectar supply. It also suffers high mortality through collision with windows, vehicles and fences. On the mainland, clearance and degradation of habitat for agriculture, forestry and residential and commercial development has had the biggest impact (D. Saunders in litt. 2007). Much of the preferred lowland habitat on the most fertile and productive sites has been cleared or substantially modified (C. Tzaros in litt. 2003). Drought refuge habitats continue to be cleared and fragmented for coastal developments (D. Saunders in litt. 2007). Remnants, including much of what currently exists in the conservation reserve system, have been heavily cut-over and degraded, and this practice is continuing in many areas, including hardwood production forests. This practice is considered to result in poor and unreliable nectar-sources through the reduction of large mature trees. Competition from large nectarivores honeyeaters and the introduced Bumblebee Bombus terrestris may be exacerbated by forest fragmentation. In winter, the species relies heavily on public land that has been exploited for timber, honey and minerals (Kennedy and Tzaros 2005).
Global warming threatens to alter habitat phenology and climatic conditions such that habitat availability may be significantly reduced (D. Saunders in litt. 2007). The species is also threatened by disturbance, Psittacine beak and feather disease and illegal bird capture and trade (D. Saunders in litt. 2007). Furthermore, the species seems to be very susceptible to Allee effects, where survival and reproductive success decline with decreasing population density, which might even accelerate the population decline (Crates et al. 2017).
Conservation and Research Actions Underway
CITES Appendix II. Management actions completed or underway include regular population surveys in Tasmania and throughout the mainland range, utilising a large network of volunteers (Saunders et al. 2007) (coordinated by the Swift Parrot Recovery Team and the Threatened Bird Network), addition of areas of critical habitat to the conservation reserve system in Victoria, development and refinement of guidelines for forestry in E. globulus and box-ironbark forests (at identified priority sites), development of community awareness programmes and revegetation and habitat rehabilitation. BirdLife Australia are calling for an immediate halt to logging activities in important breeding habitat for the species (Vine 2015).
Conservation and Research Actions Proposed
Establish an annual monitoring programme to determine trends and breeding distribution under different climatic conditions. Urgently conduct research to determine methods of reducing Sugar Glider predation on Swift Parrot nests. Conduct research on nesting distribution, breeding success and population viability. Identify nesting and foraging sites and migration routes and map these using GIS. Monitor the extent of habitat loss and alteration surrounding known sites. Develop a habitat phenology monitoring project. Place all areas of public land that support Swift Parrots under secure conservation management, particularly those in timber reserves, transport corridors and local government land. Promote revegetation and land reclamation that recreates woodland habitat. Establish incentive, conservation and management agreement and community projects each year for the protection, restoration or conservation management of habitat. Provide recommendations for the revision of threatened fauna manuals and forestry prescriptions when licence agreements are due for renewal in each state. Provide conservation information to key Local Government Areas. Engage the public in research, monitoring, management and advocacy. Produce spatial and temporal climate change models, review the potential influence of climate change on the species and identify future management strategies. Establish and maintain a collision database. Produce and distribute collision prevention brochures. Produce media releases each year for increased public awareness. Develop a monitoring protocol for Psittacine beak and feather disease and distribute information to all fauna rescue and state conservation organizations.
25 cm. Slim parrot with pointed wings and long, pointed tail. Adult male predominantly bright green with blue patch on crown and red frontal band, throat and undertail-coverts. Red blotches on flanks. Adult female slightly duller, most with prominent cream underwing-bar. Juvenile has pale orange bill and dark brown iris. Similar spp. Distinguished from Musk Lorikeet Glossopsitta concinna by red underwing-coverts, and from Scaly-breasted Lorikeet Trichoglossus chlorolepidotus by latter's scaly yellow underbody markings. Voice Often calls loudly however can also be quiet and cryptic. Calls have mellow piping tone, that differs from the harsher lorikeet calls. Hints Search areas of flowering blue gums in eastern Tasmania in summer, and eucalypts with lerps on the leaves or flowers within the mainland range during autumn-winter, especially box-ironbark forest.
Text account compilers
Symes, A., Taylor, J., Dutson, G., Allinson, T, Garnett, S., Hermes, C., Benstead, P., McClellan, R., Ashpole, J, North, A.
Tzaros, C., Saunders, D., Roderick, M., Bryant, S.
BirdLife International (2021) Species factsheet: Lathamus discolor. Downloaded from http://www.birdlife.org on 18/10/2021. Recommended citation for factsheets for more than one species: BirdLife International (2021) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 18/10/2021.