Justification of Red List Category
This large forest eagle is classified as Vulnerable on the basis of an estimated small population which is slowly declining through habitat loss and, locally at least, hunting.
Based on a territory mapping exercise in the extensive Crater Mountain Wildlife Management Area (comprising, at the time, of c.85% montane forest and c.15% cultivation), Watson and Asoyama (2001) estimated a suitable density of one pair (= two mature individuals) per 150 km2 of forest (accounting both for density and occupancy). Bryan et al. (2015) suggested an area of suitable rainforest habitat of c.250,000 km2 exists on New Guinea, suggesting a total population size of 1,600 pairs. However, since the Crate Wildlife Management Area contains habitat not suitable, and the species has also been recorded (albeit at low densities) in monsoon forest, the population is perhaps higher. Consequently, the population size of this species is estimated at 1,600-2,000 pairs, or 3,200-4,000 mature individuals.
Based on data between 2000 and 2021 (Global Forest Watch 2022, based on methods and data from Hansen et al. ), forest cover is estimated to have been reduced in this species' range by c.7-9% in the three generation period (c.30 years; Bird et al. 2020) to 2021. Given this species' forest dependence, this is thought to have caused a reduction in population size at least equal. Hunting remains a key threat to this species in areas close to villages (Watson and Asoyama 2001) and this is thought to have additive impacts, such that the population is suspected of declining at an ongoing rate of 10-19% over three generations.
Harpyopsis novaeguineae is widely distributed on New Guinea (Papua, Indonesia and Papua New Guinea). It occurs at very low population densities and occurs at most forested locations from the coast to at least 3,200 m (Beehler and Pratt 2016).
It is most common in undisturbed rainforest, but has been recorded from forest clearings and gallery forest from sea-level to at least 3,200 m (Coates 1985, Beehler and Pratt 2016). It also occurs in very low numbers within monsoon forest in the Trans-Fly (Mayr and Rand 1937, Bishop 2005). It feeds mainly on mammals, mostly marsupials and rats, but also pigs and dogs, and sometimes takes birds, lizards and snakes (Coates 1985, Beehler et al. 1992, B. Beehler in litt. 2007). It often hunts on the ground but also takes arboreal prey and extracts animals from tree-cavities (Coates 1985, Beehler et al. 1986). Only one active nest has been examined, containing a single chick, and it is possible that this species breeds less than annually (Coates 1985). The species requires extensive forest and is thought to be fairly intolerant of logged forest, however, there have been reports of the species inhabiting selectively logged forests in the upper Watut of Papua New Guinea (B. Beehler in litt. 2012) and in forest that had been logged 10 years previously (I. Woxvold pers. comm. 2016).
It is hunted in most if not all forests of New Guinea, especially the highlands, for its tail and flight feathers which are used in ceremonial head-dresses. Hunting pressure is most intense and the species is significantly less common close to densely inhabited areas, especially in mid-montane altitudes (Beehler 1985, Coates 1985, Watson and Asoyama 2001). There are only three records in four years from the heavily hunted Ok Tedi area (Gregory 1995a), but it is widespread in low numbers in the YUS Conservation Area in forests that are hunted (B. Beehler in litt. 2012) and persists despite hunting at Karimui (Freeman and Freeman 2014). It may also suffer from competition with human hunters for large mammalian prey (A. Mack in litt. 1999). There are fewer records from logged forest, where it is probably less common, and habitat is also being slowly lost to subsistence gardens and infrastructure projects. Logging roads also open up previously inaccessible areas to hunting, but in many areas (e.g. southern Papua New Guinea), logging occurs in areas of low human population density (I. Woxvold pers. comm. 2016).
Conservation Actions Underway
CITES Appendix II. It occurs in several protected areas, such as the Crater Mountain Wildlife Management Area. It is fully protected by law in Papua New Guinea, but these laws are rarely enforced.
75-90 cm. Very large, powerful eagle of forest canopies. Grey-brown upperparts including an erectile occipital ruff, barred wings and tail, pale brown upper breast, shading paler ventrally. Similar spp. In size, it is matched only by the short-tailed White-bellied Sea-eagle Haliaeetus leucogaster and the uniformly very dark brown Gurney's Eagle Aquila gurneyi. In plumage, it is similar to the smaller Long-tailed Buzzard Henicopernis longicauda and Doria's Hawk Megatriorchis doriae but has an unstreaked breast. Voice Repeated, deep, resonating calls and grunts, often at night. Hints Can be heard and occasionally seen in any large forest with limited shotgun hunting.
Text account compilers
Beehler, B.M., Bishop, K.D., Burrows, I., Diamond, J.M., Dutson, G., Kisokau, K.M., Mack, A. & Woxvold, I.
BirdLife International (2023) Species factsheet: Harpyopsis novaeguineae. Downloaded from http://www.birdlife.org on 22/03/2023. Recommended citation for factsheets for more than one species: BirdLife International (2023) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 22/03/2023.