Data Zone
Justification of Red List category
This species is endemic to the northern half of Sulawesi, where it is commonest in remote montane forest. Although its population size has not been quantified, it is not believed to be small and there is little evidence that the species is declining rapidly enough to meet or approach the thresholds for being threatened. Accordingly, it is listed as Least Concern.
Population justification
There are no empirical data available from which to estimate this species' population size and even qualitative estimations of its abundance are obfuscated by its remote distribution and by virtue of it being an infrequently observed, nocturnal species for which, until relatively recently, the vocalisations were not known (Yong et al. 2012). Even so, it is described as 'uncommon' in Eaton et al. (2021) and is evidently not an abundant species, although may be regularly observed at known, accessible sites (eBird 2023). Although a population size is not estimated herein, there is more than 100,000 km2 of forest in its mapped range, such that even if a small percentage of this is occupied, the population size is unlikely to be small. With no known acting threats on the species, there is no evidence that the contemporary population size is significantly depleted from a historic baseline.
Trend justification
The only threat known to be acting on this species is habitat loss and degradation. In the past three generations (15 years: 2007-2022), forest cover has reduced by only 2-3% in this species' range, and some of these losses are attributable to natural phenomena including landslides (Global Forest Watch 2023, based on data from Hansen et al. [2013] and methods disclosed therein). This species appears dependent on primary forest, even if it strays over clearings and tracks when foraging (Yong et al. 2012, Eaton et al. 2021), and these minor losses are suspected of causing a very slow, ongoing decline. Nonetheless, these declines are unlikely to be occurring at a rate that exceeds 5% over three generations. The range of E. diabolicus is mostly contained to forest that is considered the least susceptible to exploitation in the future (see Voigt et al. 2021), and declines are therefore unlikely to accelerate in the future.
It appears to be confined to northern Sulawesi, Indonesia, where it is known from mountain ranges on the Minahasa Peninsula and in the island's centre. Sightings from elsewhere remain unconfirmed: for example those on Buton (see Sykes 2009) and southern Sulawesi (BirdLife International 2001). Berryman and Eaton (2020) did not detect it in the Mekongga range, where they extended the distribution of other nocturnal species, including Ninox ios, suggesting that its distribution may be genuinely confined to Minahasa and central Sulawesi, although more surveys here, and in East Sulawesi, are needed.
It inhabits tropical lowland and lower montane, evergreen rainforest, from 250 m to 2,500 m (Yong et al. 2012, Eaton et al. 2021), although most records are from above 1,000 m. It is presumed to be sedentary in primary forest, including clearings and tracks through them. It has been found incubating in March to October (Boon and Faustino 2005, Yong et al. 2012, eBird 2023).
The only threat known to be acting on this species is habitat loss and degradation because of encroaching agriculture. In the past three generations (15 years: 2007-2022), forest cover has reduced by only 2-3% in this species' range, and some of these losses are attributable to natural phenomena including landslides (Global Forest Watch 2023, based on data from Hansen et al. [2013] and methods disclosed therein). This species' range is mostly contained within forest that is considered the least susceptible to exploitation in the future (see Voigt et al. 2021), and declines are therefore unlikely to accelerate in the future.
Conservation Actions Underway
Recorded from several protected areas including Lore Lindu National Park (Yong et al. 2012) and Gunung Masarang Protection Forest (Warwer et al. 2019). Even unprotected areas of this species' range are secure however due to the remoteness of the terrain.
Conservation Actions Proposed
Confirm the true limits of this species' distribution, especially surveys to determine whether it occurs in East or South-East Sulawesi provinces. Determine whether there are any other threats to this species beyond habitat loss and degradation. Continue to monitor habitat trends using remote sensing data. Propose further forested areas supporting populations of this, and other species endemic to Sulawesi, for protection.
26-27 cm. Medium-sized, dark nightjar. Greyish-brown upperparts, spotted and speckled brown, buff and tawny. Blackish streaks on crown, continuous with mantle. Brown underparts, barred and spotted cinnamon and pale buff. White band on throat but no white visible in wings or tail. Female has buff band on throat. Similar spp. Great Eared-nightjar Lyncornis macrotis is much larger and paler, with longer ear-tufts and pale nuchal collar. Female Jungle Nightjar Caprimulgus indicus, female Savanna Nightjar C. affinis and juvenile Sulawesi Nightjar C. celebensis are similar, but smaller and paler. Voice Little known, but flight calls may include weak screams, loud whirrip notes and soft churrs.
Text account compilers
Berryman, A.
Contributors
Yong, D.
Recommended citation
BirdLife International (2024) Species factsheet: Heinrich's Nightjar Eurostopodus diabolicus. Downloaded from
https://datazone.birdlife.org/species/factsheet/heinrichs-nightjar-eurostopodus-diabolicus on 25/11/2024.
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 25/11/2024.