• Summary
• Text account
• Data table and detailed info
• Distribution map
• Reference and further resources

Justification of Red List category

Although the species has a restricted range, it is not believed to approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence <20,000 km² combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). The population trend is suspected to be stable, and hence does not approach the thresholds for Vulnerable under the population trend criterion (>30% decline over ten years or three generations). Although the population size is suspected to be small, it is thought thought to be declining and thus does not approach the thresholds for Vulnerable under the population size criterion (<10,000 mature individuals with a continuing decline estimated to be >10% in ten years or three generations, or with a specified population structure). For these reasons the species is evaluated as Least Concern.

Population justification
No population estimate is known, but given its very small range (380 km²) the total population is presumed to be small, and the population is precautionarily suggested to be in the range 1,000-2,499 mature individuals.

Trend justification
It was previously described as uncommon and declining (Pratt et al. 1980, 1987), however the species is probably tolerant of some habitat modification and the impacts of existing levels of land-use change and habitat degradation may be minimal. Additionally, forest loss is minimal in this species' range (amounting to <1% in the three generations to 2021 [Global Forest Watch 2023, based on data from Hansen et al. [2013] and methods disclosed therein]), it may favour habitat edges or ecotones (R. Davis in litt. 2020) and eBird records suggest that it is commonly encountered in secondary and degraded habitat (eBird 2023). The population is therefore provisionally suspected to be stable in the absence of any known substantial threats.

Caprimulgus phalaena is endemic to the island of Palau, where it is thought to be uncommon (Holyoak 2001, Cleere 2010).

It is found in mangroves, edges of lowland forest or damp, shady forest (Holyoak 2001, Cleere 2010). It may favour habitat edges or ecotones (R. Davis in litt. 2020). It roosts on the ground in leaf litter or perched length ways along branches (N. Cleere in litt. 2016). It hunts low along the ground and on invertebrates including moths, beetles, grasshoppers, locusts, flying ants and wasps (N. Cleere in litt. 2016). The breeding biology is unknown (Pratt and Etpison 2008).

The species is probably tolerant of some habitat modification, and the impacts of existing levels of land-use change and habitat degradation may have only had minimal impacts. Its ground-nesting habitat may render it highly vulnerable to predation by cats, dogs and rats (R. Davis in litt. 2020). The potential arrival of invasive predators such as Brown Tree Snake Boiga irregularis could present a future threat, although this is highly uncertain.

Conservation Actions Underway
No targeted conservation actions for this species are known.

Conservation Actions Proposed
Survey to quantify the population size.

21-23 cm. A fairly small, brown nightjar with chestnut-brown on the mantle, back and central tail feathers. Cryptically patterned with white tips to all but the central tail feathers and a small white patch on the outer primaries in the male; in the female these areas are chestnut-brown. The undertail and underwing coverts are almost entirely black. Similar species. C. indicus is considerably larger and greyer, has rufous-barred undertail and underwing coverts and larger white patches in the wing and tail. Voice. Apparently not confirmed.

Text account compilers
Vine, J.

Contributors
Cleere, N. & Davis, R.

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Recommended citation
BirdLife International (2025) Species factsheet: Palau Nightjar Caprimulgus phalaena. Downloaded from https://datazone.birdlife.org/species/factsheet/palau-nightjar-caprimulgus-phalaena on 02/01/2025.
Recommended citation for factsheets for more than one species: BirdLife International (2025) IUCN Red List for birds. Downloaded from https://datazone.birdlife.org/species/search on 02/01/2025.