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.
Red List criteria met
Red List history
IUCN Red List criteria met and history
||not a migrant
Population justification: The abundance of Fernwrens is calculated from the density and distribution of birds using data from standardised transect surveys along elevational gradients and the area of climatically suitable habitat at different altitudes in 2016 (Williams et al. 2021). The population is estimated at 450,000-1,000,000 mature individuals, with a best estimate of 660,000 mature individuals.
Trend justification: There appears to have been a substantial decline in population size in the last ten years, as predicted from climate change modelling (Williams et al. 2003). Annual monitoring undertaken 2000–2016 (1,970 plots, 62 different locations, 0–1,500 m altitude) revealed a highly significant decline of 57% in the total population over the ten years to 2016 from an estimated 1.54 million to 660,000 individuals. There were never many at low altitudes (<450 m), and the species appears to have disappeared at some lower sites (360–400 m) where it was present in the late 1990s (J. Grant unpublished, in Williams et al. 2021). Numbers increased at medium altitudes (450–850 m) until 2006 but declined after 2008-2012. At higher altitudes (>850 m), which has the smallest area, numbers rose until 2006 and stayed steady until monitoring stopped in 2016 (Williams & de la Fuente 2021). However, ongoing climate change is suspected to have the same impact on higher altitudes as it did at medium altitudes in the next three generations and so the rate of decline is broadly estimated to be the same.
Important Bird and Biodiversity Areas (IBA)
BirdLife International (2023) Species factsheet: Oreoscopus gutturalis. Downloaded from
http://datazone.birdlife.org/species/factsheet/fernwren-oreoscopus-gutturalis on 04/12/2023.
Recommended citation for factsheets for more than one species: BirdLife International (2023) IUCN Red List for birds. Downloaded from
http://datazone.birdlife.org on 04/12/2023.