Data Zone
Justification of Red List category
The population size may be moderately small to large given uncertainties, but this species has a very large range and the population appears to be stable. For these reasons, the species is assessed as Least Concern.
Population justification
The population size of Gouldian Finches has been estimated using a number of methods: Legge et al. (2021) based their estimate on the product of three suspected AOO values: the minimum AOO is based on the number of 2x2 km squares encompassing all records since 1990, the best estimate is ten times this, and the maximum double the latter. These AOO values are applied to a density estimated for Mornington Wildlife Sanctuary, Western Australia (500–1,000 adult birds in 200 km2; Legge et al. 2021). Although using genetic techniques, the effective population size (Ne) was estimated to be 1,600 (611–20,000) in 2016 (Bolton et al. 2016), the ratio of Ne to the actual number of mature individuals can vary by two orders of magnitude (Palstra and Fraser 2012) and tends to decline as populations increase (Waples et al. 2018). On eBird (2021) the sum of the maximum number of birds in any count at 113 sites (each ≥10 km apart) reported during 2018–2019 was 3,915 mature individuals. Such counts are prone to some inflation from recounting the same individuals as they come and go from the field of view and >80% of birds in flocks are usually juveniles (Woinarski and Tidemann 1992, Franklin et al. 1998), so the number of mature individuals is much smaller than the numbers counted in flocks. Given these uncertainties, the estimate used here is set at 5,000-50,000 mature individuals, with a best estimate of 25,000.
Trend justification
Consistent with analyses undertaken in 2015 (TSSC 2016), there was zero trend in reporting rate from 2000–2019 for both 2-ha 20-min surveys and 500-m radius area surveys (BirdLife Australia 2020). Count data from standardised waterhole counts conducted at sites in the Northern Territory (1996–2004; O'Malley 2006) also showed no decline, while the known AOO expanded by 36% between 1999-2009 and 2010-2020, although there remains uncertainty whether this constitutes an expansion in range of survey effort.
The species occurs in northern Australia on Cape York Peninsula, the Einasleigh Uplands and then continuously from north-west Queensland and the northern Northern Territory to the Dampier Peninsula in the Kimberley region of Western Australia (Higgins et al. 2006, O'Malley 2006). Non-breeding birds disperse widely: banded juveniles have moved 200 km in a few weeks and vagrants have been recorded on the edge of the Simpson Desert 1000 km south of the normal distribution (Legge et al. 2021). Genetic analyses suggest no structuring of the population (Esparza-Salas 2007, Bolton et al. 2016). The irregular nature of observations across their range makes it difficult to distinguish newly encountered sites from genuine expansions of range but it appears to have been observed with increasing frequency since c.2015 in the Roper Valley, Phelp River Floodplain and South Western Gulf of Carpentaria in the Northern Territory to the Queensland Border west to Daly Waters and south of Top Springs (Legge et al. 2021).
It lives in open, tropical woodland with a grassy understorey, nesting almost exclusively in tree-hollows. Known breeding habitat in the Northern Territory and Western Australia is characterised by rocky hills with smooth-barked gums Eucalyptus brevifolia or E. tintinnans within two to four kilometres of small waterholes or springs that persist throughout the dry season (O'Malley 2006). In the non-breeding season, it may occur in a slightly wider variety of woodland habitats. Throughout the year, it feeds mostly on grass seeds, sometimes taking invertebrates (S. Legge in litt. 2007). Dry season feeding habitat is dominated by annual spear grasses or native sorghum Sarga species (O'Malley 2006). In the wet season birds shift to scattered patches of cockatoo grass Alloteropsis semialata, golden beard grass Chysopogon fallax or spinifex Triodia-dominated communities. Other important wet season grasses include giant spear grass Heteropogon triticeus, white grass Sehima nervosum, ricegrass Xerochloa laniflora and kangaroo grass Themeda triandra (O'Malley 2006). The range of the Gouldian finch can change substantially, possibly related to the high mobility of the species, or the fluctuations in range between years (S. Pryke in litt. 2012).
Regular extensive fires and over-grazing by cattle are known to reduce body condition and other health indices, particularly during the late dry season and early wet season (Legge et al. 2015). Cattle and other livestock cause changes in grass species composition and phenology, with the most severe impact probably due to a reduction in the abundance of grass species that set seed earliest in the wet season (J. Woinarski in litt. 2007). Wet season grasses that are essential to the species are grazed by cattle, horses and feral pigs, whilst cattle and buffalo can degrade waterholes used by the species through trampling and grazing of the surrounding vegetation (O'Malley 2006). Current fire regimes may be exacerbating the impact of herbivores, obliterating the mosaics of burnt and unburnt habitat the birds require. Fire is known to impact the seed productivity of key wet season grasses that the species relies on during the period of food scarcity that occurs early in the year, and the species also tends not to nest in burnt tree-hollows (O'Malley 2006). The modern fire regime in northern Australia is dominated by frequent, extensive, hot, late dry season wildfires over large tracts of land (O'Malley 2006). Research by Legge et al. (2015) showed indices of body condition to be lower for individuals exposed to extreme fire regimes, compared to their counterparts in less frequent and less intense fire regions. These differences in body condition suggest increased activity to find food, greater food uncertainty and prolonged food deprivation. Fire affects choice of nest site (Weier et al. 2016) and, in some areas, nest hollow availability, although these appear not to be limiting at most sites (Tidemann et al. 1999; Brazill-Boast et al. 2010, 2011). However, the threat of fire has been mitigated at some sites through active management (Legge et al. 2011, Evans and Russell-Smith 2020). Queensland populations breed in areas of low livestock grazing pressure and low to moderate fire frequency of a mosaic nature, including storm burns (R. Pierce unpublished). Historically, an air-sac mite Sternostoma tracheacolum (Tidemann et al. 1992, Bell 1996) also appeared to increase mortality in the wild and may have been a proximal cause of the decline in a population already stressed by environmental change, but its occurrence in wild populations has not been noted in recent decades. Trapping for aviculture was substantial in the past but has not occurred to any extent for 30 years. There may be ongoing localised threats to some breeding habitat from development such as mining. The impacts of climate change are hard to determine: the species is projected to have an increase in suitable climate space by the end of the century (Reside et al. 2012, 2015) but climate change is predicted to affect the timing and quantity of wet season rainfall, potentially increasing the frequency or intensity of wildfires, altering the abundance of important grass species and changing the availability of surface water during the dry season (O' Malley 2006).
Conservation Actions Underway
Management actions completed or under way include the implementation of a recovery plan, the establishment of regional operations groups, detailed research on fire, food and movements at Mornington Wildlife Sanctuary, Kimberley, the collation and maintenance of a database of all known sight records and a review of the patterns of the distribution, habitats, potential threats and conservation status of savanna granivorous birds. Attempts at reintroduction have so far had equivocal results (S. Garnett in litt. 2007). There is an ongoing monitoring programme at four sites (J. Woinarski in litt. 2007, S. Legge in litt. 2007) and captive-breeding populations exist (DSEWPC 2013).
11-12.5 cm. Gaudy finch with pointed, black tail. Adult is among the most colourful of birds. Grass-green upper body from lower nape to back and wings, browner remiges. Black, red, or rarely, orange-yellow head and throat, narrowly bordered posteriorly with black and pale blue. Pale blue rump. Purple breast. Bright yellow belly. Whitish bill with red tip. Female duller on underside. Juvenile ashy-grey on head and neck, paler below and olive-grey on upper body and wings. Similar spp. Adult unmistakable. Juvenile more olive and bulkier than other finches. Voice Sibilant sitt, repeated. Hints Gather at waterholes to drink in dry season.
Text account compilers
Vine, J., Garnett, S.
Contributors
Benstead, P., Brazill-Boast, J., Garnett, S., Legge, S., McClellan, R., North, A., Pryke, S., Symes, A., Taylor, J., Temple, H. & Woinarski, J.C.Z.
Recommended citation
BirdLife International (2024) Species factsheet: Gouldian Finch Chloebia gouldiae. Downloaded from
https://datazone.birdlife.org/species/factsheet/gouldian-finch-chloebia-gouldiae on 23/12/2024.
Recommended citation for factsheets for more than one species: BirdLife International (2024) IUCN Red List for birds. Downloaded from
https://datazone.birdlife.org/species/search on 23/12/2024.