CR
Baudin's Black-cockatoo Zanda baudinii



Justification

Justification of Red List Category
This species is experiencing very rapid declines exceeding a rate of 90% over the past three generations due to nest hollow shortages, displacement by other species, hunting and increasing declines in the quality of habitat caused by fires and drought. There is no reason to suggest these declines will cease with nest hollow shortages continuing to afflict the species with low productivity, and fire and drought impacts projected to worsen with ongoing anthropogenic climate change. With a relatively small population (likely comprising fewer than 4,000 mature individuals), future declines of this magnitude place Baudin's Black-cockatoo at considerable extinction risk; it is therefore listed as Critically Endangered.

Population justification
The population of this species is well monitored by annual counts of roost sites that combined are believed to constitute 90-95% of the species' total population size. From these counts, the total number of Baudin's Black-cockatoos was estimated at 10,000–15,000 individuals in 1995–2004 and 5,000–8,000 in 2017 of which 2,500–4,000 are estimated to be mature individuals (TSSC 2018). Following Johnstone et al. (2021), the best estimate is placed at 3,250 mature individuals.

Trend justification
This species is in steep decline. Monitoring of traditional roost sites in the northern Jarrah-Marri forest (the wintering area for c.95% of the population) has shown precipitous declines over the past three generations (Johnstone & Kirkby 2019, Peck et al. 2019, Johnstone et al. 2021). For example, the Araluen roost declined from 800 birds in 2006, to 0 in 2014 and 2015; at Wungong, numbers declined from 600 in 1998 and 2006, to fewer than 50 in monitoring 2014-2020; counts at Myara declined from 500 in 2007 to fewer than 100 in 2015 (R. Johnstone in litt. 2022). These declines are inferred to relate directly to abundance with these losses not compensated by gains elsewhere. Further evidence is provided from the Darling Scarp and Plateau region, where mixed flocks of Z. baudinii and Z. latirostris (thought to be approximately 70% the former) have been declining at a rate of c.8% per year (Peck et al. 2019). Consequently, the population is inferred to have declined by more than 90% over the past three generations (Johnstone et al. 2021). These declines are projected to continue: nest hollow shortages are causing ongoing poor productivity, while projections of heat, drought and fire all suggest less forest food and fewer sites with accessible drinking water will be available between now and 2062 (Johnstone et al. 2021). Declines are therefore suspected to occur at a similar rate (set here to 80-99%), with no amelioration of the threats facing the species apparent.

Distribution and population

Z. baudinii is endemic to higher rainfall parts of the south-west of Western Australia (Johnstone and Kirkby 2008) from Gidgegannup and Hoddy Well south-east to the Stirling and Porongurup Ranges and along the south coast to Waychinicup National Park (Johnstone and Storr 1998, Higgins 1999, TSSC 2018). Breeding occurs in summer primarily in the south, from Nornalup north to near Bridgetown but sometimes further north to Lowden and Harvey. In winter, many birds move to the Darling scarp south-east of Perth (Higgins 1999, Yeap et al. 2015) although some birds remain in southern areas (Rycken 2019, BirdLife Australia 2020).

Ecology

Z. baudinii occurs in temperate forest and woodland dominated by jarrah Eucalyptus marginata, karri E. diversicolor and marri Corymbia calophylla (Johnstone et al. 2010, TSSC 2018) as well as orchards (Chapman 2007), suburban parks and roadsides (Rycken 2019, Rycken et al. 2020) and rehabilitated mine sites (Lee et al. 2013). Favoured feed trees tend to occur on lower slopes (Biggs et al. 2011) and riparian areas (Rycken 2019). They use their long upper mandible to extract marri nut seeds without crushing the fruit (Cooper et al. 2002) as well as taking seeds of jarrah, proteaceous shrubs including Banksia spp., cultivated apples and pears, and insect larvae (Halse 1986, Johnstone and Kirkby 2008, Johnstone et al. 2010). They raise a single offspring from 1–2 eggs laid in hollows of mature eucalypts (Johnstone et al. 2010) with a success rate of c. 60% (Johnstone and Storr 1998).

Threats

Nest hollow shortage is considered the principal threat as suitable hollows are considered scarce, only forming in trees at least 120 years old (Whitford et al. 2015). Many suitable trees have been preferentially felled for their timber (Abbott and Whitford 2001, Chapman 2008) and continue to be lost to mining (Chapman 2008), and there is competition for remaining hollows from Z. latirostris, white cockatoos Cacatua spp., Polytelis anthopeplus,  Chenonetta jubata and European honey bees Apis mellifera all successfully displacing Baudin's Black-cockatoos (Johnstone and Kirkby 2008, Chapman 2008, TSSC 2018). Fire, both wildfire and controlled burns, destroys nest trees, may promote disease of nest and feeding trees and can reduce the availability of food from mature marri (Mastrantonis et al. 2019), a threat likely to intensify if the probability of fire continues to increase (Clarke et al. 2016). Plant diseases are also affecting food and nest trees (Johnstone and Kirkby 2019), an effect exacerbated by drought and heat waves (Matusick et al. 2018). Although the species has been fully protected since 1996 (Mawson and Johnstone 1997), illegal shooting by orchardists may still occur where they feed on apples and pears (Chapman 2007). Because the cockatoos can cause substantial economic damage (Halse 1986), efforts made to conserve the species historically have been less vigorous than for Z. latirostris (Ainsworth et al. 2016). The availability of freshwater for drinking may also limit numbers in dry years, given current trends in water availability in south-western waterways (Barron et al. 2012). Projections of heat (Herold et al. 2018), drought (Dey et al. 2019) and fire (Di Virgilio et al. 2019, Dowdy et al. 2019) all suggest future declines in forest food and sites with accessible drinking water.

Conservation actions

Conservation Actions Underway
CITES Appendix II. Protected under Australian law since 1996. Substantial parts of its range are within protected areas. Priority actions have been identified, primarily limiting illegal shooting and loss of mature trees (TSSC 2018). There is increasing enforcement of controls on shooting (Johnstone et al. 2021).

Conservation Actions Proposed
A census of breeding locations is urgently needed to determine robust estimates of total population size, the extent and quality of breeding habitat, and any trends in breeding sites/success. Obtain robust estimates of adult and juvenile survival rates across the range. Improve understanding of the dynamics of hollow creation and loss, including the role of fire and the influence of fire regimes and develop an adaptation strategy. Identify how to reduce the effect of competition for hollows with other native bird species (Johnstone et al. 2021). Assist orchardists in developing a non-lethal damage mitigation strategy (Chapman 2007). Manage areas of habitat to help retain hollow-bearing trees. Prevent illegal shooting in and around commercial orchard areas and strengthen compliance with laws to protect the species from shooting. Manage rivers and streams to guarantee adequate water supplies during periods of prolonged drought. Continue to raise awareness of the species' status amongst orchardists and promote non-lethal control methods. Develop and implement a feral bee control strategy.

Identification

55-60 cm, 540-790 g. Dull black cockatoo with broad and conspicuous buffish margins over body feathers. Large greyish-white ear-covert patch. Tail shows broad subterminal white panel, with central two feathers all black. The two sexes are very similar, but females have periophthalmic skin dark grey (not pink) and paler bill. Voice Typical call a quite high-pitched slurred squealing “kweEE-ah”.

Acknowledgements

Text account compilers
Vine, J., Berryman, A.

Contributors
Garnett, S. & Johnstone, R.


Recommended citation
BirdLife International (2022) Species factsheet: Zanda baudinii. Downloaded from http://www.birdlife.org on 04/10/2022. Recommended citation for factsheets for more than one species: BirdLife International (2022) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 04/10/2022.