Allied Owlet-nightjar Aegotheles affinis


Justification of Red List Category
Very little is known about this newly-split and elusive owlet-nightjar, and based on currently available information it is not possible to estimate the range size, population size or trend. It is therefore classified as Data Deficient.

Population justification
The global population size has not been quantified, but the species is thought to be uncommon (Cleere 2010).

Trend justification
It is not possible to derive a reliable estimate of the population trend from available information, although the species is unlikely to be in rapid decline, given rates of forest loss in the vicinity of its known locations. Deforestation rates of c.11-15% over 30 years (1972-2002) have been estimated in the Western Highlands and Southern Highlands of Papua New Guinea (Shearman et al. 2009), reducing to 1% loss over the highlands between 2002-2014 (Bryant and Shearman 2015). Overall forest loss in West Papua has been estimated at 2.4% over 10 years (2000-2010) (Miettinen et al. 2011). The species is thought to have a three-generation trend period of c.16 years, thus it is unlikely that its population trend has approached a decline of 30% over three generations.

Distribution and population

Aegotheles affinis is represented by two subspecies: the nominate A. a. affinis is known only from the Vogelkop Mountains in West Papua province, Indonesia, while A. a. terborghi (sometimes also considered as a subspecies of A. bennettii: Beehler and Pratt 2016) is known from a single specimen collected in 1964 and one sighting in 2016 in the Karimui Basin in Eastern Highlands province, Papua New Guinea (Diamond 1967, Banwell 2016). It is very poorly-known, although it inhabits forest and is thought to be uncommon (Cleere 2010). Few specimens of any owlet-nightjars have been collected in the region between the known localities of affinis and terborghi and future surveys may fill this apparent range gap (Dumbacher et al. 2003).


A. a. affinis has been recorded at up to c.900 m in the Vogelkop Mountains (Rand and Gilliard 1967), while the two records of A. a. terborghi came from 1,100 m  and 1,530 m (Diamond 1967, Banwell 2016), with a range of 800 - 1,500m (and perhaps lower) being cited by Pratt and Beehler (2015). The habitat appears to be hill forest.


This species is likely to be threatened to some degree by industrial logging and forest clearance for subsistence gardens.

Conservation actions

Research Actions Proposed
Research is required into its calls, population size and distribution.
Research its tolerance of degraded habitats including logged forest and subsistence gardens.


Text account compilers
Butchart, S., Dutson, G., Ekstrom, J., Symes, A., Taylor, J. & North, A.

Recommended citation
BirdLife International (2022) Species factsheet: Aegotheles affinis. Downloaded from http://www.birdlife.org on 06/12/2022. Recommended citation for factsheets for more than one species: BirdLife International (2022) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 06/12/2022.