NT
Golden Bowerbird Prionodura newtoniana



Justification

Justification of Red List category
This species has a small range and the population is thought to be declining at a rate of more than 20% over three generations as a result of climate change. For these reasons the species is assessed as Near Threatened.

Population justification
The abundance of Golden Bowerbirds is calculated from the density and distribution of birds and the area of climatically suitable habitat at different altitudes in 2016 (Williams et al. 2010a).

Trend justification
The declining trend is derived from annual monitoring undertaken from 2000–2016 (1,970 plots, 62 different locations, at 0–1,500 m; Williams and Fuente 2021), which suggest a 56.8% decline in the total population over the three generations to 2016 but a high interannual variability meant that it was not statistically significant. Also, contrary to models of climate change impact (Williams et al. 2003; Hilbert et al. 2004), the apparent decline was greatest at higher altitude (>850 m) sites with trends at mid-altitude (450–850 m) sites steady. Similarly, although reporting rates declined by 40% between the first Atlas 10 min grids (1977–1981) and in 500-m and 5-km area searches in the second Atlas (1988–2001; Garnett et al. 2003), there was no trend in rates from 500-m area searches between 1999 and 2018 (BirdLife Australia 2020). Regular visits to 82 bowers across the species's range since have noted only three as being abandoned, at 1485 m, 1195 m, and 635 m. However, monitoring of trends in bower occupancy has been complicated by the effects of Cyclones Larry (2006) and Yasi (2011) which destroyed many bower sites and then rendered some unsuitable because the regrowth was too dense (D. Chaplin, G.N. Harrington unpublished, in Williams et al. 2021). Detectability functions were also impacted (Williams and de la Fuente 2021). Evaluating all trends over the past three generations and accounting for fluctuations (particularly in detectability) caused by cyclones, Williams et al. (2021) concluded that the population is expected to have declined at a rate of 20-29% over the past three generations, however the nature of the monitoring and inferences mean that there is much uncertainty. Given the ongoing nature of the threats, the population is suspected to decline at a similar rate in the future.

Distribution and population

Golden Bowerbirds are endemic to higher altitudes in the Queensland Wet Tropics region, Australia with bowers found from Mt Finnigan in the north, south to Paluma and inland as far as the Herberton Range and the Windsor Tableland (Frith and Frith 2004; D. Chaplin and G. Harrington unpublished, in Williams et al. 2021).

Ecology

Golden Bowerbirds occur in upland rainforest at 350-1,530 m, with 90% of 119 known bowers above 900 m and 85% above 1,000 m (D Chaplin, GN Harrington unpublished, in Williams et al. 2021), the altitude above which they occur at the highest densities (Williams et al. 2010b), although some female-plumaged birds descend to lower altitudes in winter (Frith and Frith 2004). They feed on fruit and invertebrates gleaned primarily from the canopy (Frith and Frith 2004) and lay 1–2 eggs in a bulky cup nest usually built within a vertical crevice in a tree trunk (Frith and Frith 1998). Males maintain elaborate display bowers (Frith and Frith 2000a, 2000b).

Threats

Climate change is the only known threat and could be having both direct effects as a result of increased mortality during heat waves, which have been longer and hotter in the last two decades, and an indirect effect because the dry season has been longer, drier and hotter, which is likely to have reduced resource availability (Williams et al. 2010b, Williams and de la Fuente 2021).

Conservation actions

Conservation Actions Underway
Almost entire range within protected areas.

Conservation Actions Proposed
Understand constraints on population size and survival.  Identify reasons for sensitivity to climate change and options for countering them.  Develop strategies for maintaining remaining populations. Apply adaptation strategies as required.

Acknowledgements

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


Recommended citation
BirdLife International (2024) Species factsheet: Golden Bowerbird Prionodura newtoniana. Downloaded from https://datazone.birdlife.org/species/factsheet/golden-bowerbird-prionodura-newtoniana on 22/12/2024.
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 22/12/2024.