NT
Tooth-billed Bowerbird Scenopoeetes dentirostris



Taxonomy

Taxonomic source(s)
Christidis, L. and Boles, W.E. 2008. Systematics and Taxonomy of Australian Birds. CSIRO Publishing, Collingwood, Australia.
del Hoyo, J., Collar, N.J., Christie, D.A., Elliott, A., Fishpool, L.D.C., Boesman, P. and Kirwan, G.M. 2016. HBW and BirdLife International Illustrated Checklist of the Birds of the World. Volume 2: Passerines. Lynx Edicions and BirdLife International, Barcelona, Spain and Cambridge, UK.

IUCN Red List criteria met and history
Red List criteria met
Critically Endangered Endangered Vulnerable
- - -

Red List history
Year Category Criteria
2022 Near Threatened A2bc+3c+4bc
2016 Least Concern
2012 Least Concern
2009 Least Concern
2008 Least Concern
2004 Least Concern
2000 Lower Risk/Least Concern
1994 Lower Risk/Near Threatened
1988 Lower Risk/Least Concern
Species attributes

Migratory status not a migrant Forest dependency medium
Land-mass type Average mass -
Range

Estimate Data quality
Extent of Occurrence (breeding/resident) 31,300 km2
Severely fragmented? no -
Population
Estimate Data quality Derivation Year of estimate
Population size 19000-460000, 239500 mature individuals poor estimated 2020
Population trend decreasing - inferred 1996-2022
Rate of change over the past 10 years/3 generations (longer of the two periods) 20-29% - - -
Rate of change over the future 10 years/3 generations (longer of the two periods) 20-29% - - -
Rate of change over the past & future 10 years/3 generations (longer of the two periods) 20-29% - - -
Generation length 8.6 years - - -
Number of subpopulations 3-5 - - -
Percentage of mature individuals in largest subpopulation 1-89% - - -

Population justification: The abundance of Tooth-billed Bowerbirds was calculated from the density and distribution of birds and the area of climatically suitable habitat at different altitudes (Williams et al. 2010a).

Trend justification: There is much uncertainty with the rate of decline in this species. Annual monitoring between 2000 and 2016 (at 1,970 plots at 62 different locations, spanning 0-1,500 m altitude) detected a highly significant rapid decline from 460,000 to 20,000 mature individuals (equivalent to a >95% decline over three generations [25.8 years; Bird et al. 2020]) at both mid- and high-altitude sites. Similarly, reporting rates for 2-ha 20-min surveys declined by 51% from 1999–2018, again with most of the decline in the first ten years (BirdLife Australia 2020). There was also a significant decline in reporting rate of 30%–42% between the first BirdLife Australia Atlas (1977–1981) and the second (1998–2001; Barrett et al. 2002, Garnett et al. 2003). However, many of these reductions are attributable to Cyclones Larry (2006) and Yasi (2011) which severely damaged many court sites, probably killed many birds, and diminished the frequency of calls, and thus detection rates for many years afterwards - declines caused by these events are considered temporary and there were signs of recovery post 2008 in the data. Moreover, there was little change in the reporting rates from 500-m radius area searches from 1999–2018 (BirdLife Australia 2020), no difference between 2000–2007 and 2013–2019 in the proportion of weeks in which the species was recorded (from 33% and 34%) at the School for Field Studies Centre near Danbulla (740–780 m; A. Freeman, M. Craig unpublished, in Williams et al. 2021) and visits within the last five years to almost all known historic locations found none had been vacated. Evaluating all trends over the past three generations, Williams et al. (2021) concluded that the population is suspected to have declined at a rate of 20-29% over the past three generations, principally because of climate change, which is reducing population sizes in a large number of Wet Tropics species (William and de la Fuente 2021). Given the ongoing nature of this threat, the population is suspected to decline at a similar rate in the future, although there are many uncertainties with these estimations.


Country/territory distribution
Country/Territory Presence Origin Resident Breeding visitor Non-breeding visitor Passage migrant
Australia extant native yes

Important Bird and Biodiversity Areas (IBA)
Country/Territory IBA Name
Australia Daintree
Australia Paluma
Australia Wooroonooran

Habitats & altitude
Habitat (level 1) Habitat (level 2) Importance Occurrence
Artificial/Terrestrial Pastureland suitable resident
Forest Subtropical/Tropical Moist Lowland major resident
Altitude 500 - 900 m Occasional altitudinal limits 20 - 1220 m

Threats & impact
Threat (level 1) Threat (level 2) Impact and Stresses
Climate change & severe weather Habitat shifting & alteration Timing Scope Severity Impact
Ongoing Whole (>90%) Slow, Significant Declines Medium Impact: 7
Stresses
Indirect ecosystem effects, Ecosystem degradation
Climate change & severe weather Storms & flooding Timing Scope Severity Impact
Ongoing Unknown Unknown Unknown
Stresses
Ecosystem degradation, Species mortality
Climate change & severe weather Temperature extremes Timing Scope Severity Impact
Ongoing Whole (>90%) Slow, Significant Declines Medium Impact: 7
Stresses
Species mortality

Recommended citation
BirdLife International (2024) Species factsheet: Tooth-billed Bowerbird Scenopoeetes dentirostris. Downloaded from https://datazone.birdlife.org/species/factsheet/tooth-billed-bowerbird-scenopoeetes-dentirostris on 22/11/2024.
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 22/11/2024.