Data Zone
Justification of Red List category
This species's population is suspected to be small, with potentially none of the three subpopulations numbering more than 1,000 mature individuals. It is also suspected to be declining because of ongoing forest loss. For these reasons, it is assessed as Near Threatened.
Population justification
Population numbers and trends are difficult to assess from so few recent records, but the species has been considered to be rare (K. D. Bishop in litt. 1994, D. Gibbs in litt. 1994, G. Dutson pers. obs. 1998). Ferguson-Lees and Christie (2001) estimated the global population to be in "the low hundreds". However, a visit to Bougainville led Hadden (2008) to suspect that the species may be reasonably common in the forest interior throughout the island, given the mist-net capture of two individuals in relatively few net-hours. Based on density estimates of congeners (first quartile and median: 0.5 and 2 individuals per km2, the area of tree cover with at least 50% canopy cover within the species's mapped range (c.8,850 km2; Global Forest Watch 2022, using Hansen et al. [2013] data and methods disclosed therein) and assuming 25-40% of forest within the species's range is occupied, the population size is tentatively inferred to fall within the range 1,100-7,080 individuals, roughly equating to c.725-4,700 mature individuals and placed in the band 700-5,000 mature individuals. Assuming a separate subpopulation on each island, Bougainville, which contains approximately 55% of the total forest cover within the species's range (Global Forest Watch 2020), is inferred to comprise 385-2,750 mature individuals. Given the paucity of records despite extensive effort by ornithologists and birdwatchers (see, for example, eBird [2021]), and the suspicion from Ferguson-Lees and Christie (2001) that the total population of this species was in the low hundreds, it is precautionarily accepted that there are likely to be a best estimate of 1,001-2,000 mature individuals, with a best estimate of 500-1,000 mature individuals in the largest subpopulation. Generating accurate population data on this species should be considered a priority.
Trend justification
The species appears to have declined in the past, on Choiseul at least (K. D. Bishop in litt. 1994, D. Gibbs in litt. 1994, G. Dutson pers. obs. 1998). Based on remote sensing data showing a small amount of deforestation within the species's range from 2006-2020 (Global Forest Watch 2022, using Hansen et al. [2013] data and methods disclosed therein), the species is suspected to be declining. Five percent of forest with at least 50% canopy cover was lost within the species's range over three generations (14 years; Bird et al. 2020) between 2006 and 2020. The species is highly forest dependent and known to be rare in degraded forest and is consequently suspected to have declined over a similar rate over the past three generations, here placed in the band 1-9%. Assuming a constant rate of ongoing deforestation, the species is tentatively suspected to undergo a decline of 1-9% over the next three generations (14 years).
Accipiter imitator is endemic to Bougainville, Papua New Guinea, and Choiseul and Santa Isabel, Solomon Islands. It is known from few records, but may be overlooked because of its unobtrusive forest habits, and it perhaps lacks a distinctive call. During many weeks of fieldwork on all three islands in the 1980s and 1990s, it was seen only once on Bougainville (Hadden 1981) and there was a series of records from Tirotonga village on Isabel. One specimen was also taken there, and another at a lowland site along the Garanga River, also on Isabel (Kratter et al. 2001, LeCroy et al. 2001), but some of the other field records and local reports, including those of all-black individuals, have been queried (Webb 1992, 1995, Debus 1995). The species was recorded at one site on Choiseul in 2014 (Boseto and Pikacha 2015) and on a ridge leading to the summit of the Kubonitu-Sasari massif, Isabel in 2018 (DeCicco et al. 2019).
This species has been collected and sighted in lowland forest or forest edge, and in mossy montane forest to 1,100 m (Webb 1992, 1995, Debus 1995, Dutson 2011, DeCicco et al. 2019). One was seen feeding on a Chestnut-bellied Monarch Monarcha castaneiventris (Webb 1997). Its ecology is poorly known and its niche separation from A. albogularis is unknown, but its shorter wings and tail and longer legs suggest that it is better adapted to interior forest (Schodde 1977).
As a lowland and hill species with almost all records from old-growth forest, it is likely to be threatened by forest loss and degradation which is ongoing on all three islands (Global Forest Watch 2022, using Hansen et al. [2013] data and methods disclosed therein).
Conservation Actions Underway
CITES Appendix II. No conservation measures are known to have been taken.
28-33 cm. Small, pied hawk with black- and white-throated and possibly all-black morphs. Adult jet-black above, the throat and breast either black or white. Reddish-brown iris. Immatures mottled rufous with fine black barring on underparts. Similar spp. White-throated birds very similar to Pied Goshawk A. albogularis which is dark grey above, often with rufous collar, paler grey undersides to wing and tail and orange iris. Immature has dark streaks and drop-marks on the underparts. Voice Wailing reo. Possibly also a chatter. Hints Check all pied hawks on the three islands.
Text account compilers
Wheatley, H., Berryman, A.
Contributors
Bishop, K.D., Dutson, G., Gibbs, D. & Van der Ploeg, J.
Recommended citation
BirdLife International (2024) Species factsheet: Imitator Goshawk Accipiter imitator. Downloaded from
https://datazone.birdlife.org/species/factsheet/imitator-goshawk-accipiter-imitator on 21/12/2024.
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 21/12/2024.