Justification of Red List category
Although this species may have a restricted range, it is not believed to approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence <20,000 km² or Area of Occupancy <2,000 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 size has not been quantified, but it is not believed to 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). The population trend is not known, but the population is not believed to be decreasing sufficiently rapidly to approach the thresholds under the population trend criterion (>30% decline over ten years or three generations). For these reasons the species is evaluated as Least Concern.
There are no direct estimates of the species's population density or population size. On Espiritu Santo, it was recorded as present between 500 and 1,400 m asl, and common between 800 and 1,200 m in the West Santo mountains (S. Totterman pers. obs. 2010). During surveys in the Espiritu Santo uplands in 2002-2003, the species was uncommon at Wunarohaehare and common at Tsaraepae, where 20 were sometimes recorded on a single day (Kratter et al. 2006). It has been found to be common on Vanua Lava (Parr 2007). It appears to be rare on Ambae (none seen or heard in several days birdwatching in the montane forest [S. Totterman in litt. 2007]).
According to remote sensing data, there were approximately 3,540 km2 of forest with at least 50% canopy cover within the species's range in 2010 (Global Forest Watch 2021). Based on the minimum and first quartile recorded densities of congeners (1.1 and 14.5 individuals/km2, respectively), the area of tree cover stated above, and assuming that tree cover to be one to two thirds occupied, the population size is tentatively suspected to fall in the range 1,200 - 35,000 individuals, roughly equating to 800 - 23,000 mature individuals. Given that the species has been described as common in parts of Espiritu Santo and on Vanua Lava, the true population size is unlikely to fall very close to the minimum end of this range, and the best estimate is here placed in the range 2,500 - 23,000 mature individuals.
Its population structure is poorly known but it is precautionarily assessed as having separate subpopulations on each of the main islands. The species's range on Espiritu Santo has the largest area of tree cover, estimated at 2,500 km2 (approximately 70% of the total; Global Forest Watch 2021), which may translate to a population of 600-16,000 mature individuals according to the method used above, but is suspected to be larger than 1,000 mature individuals (G. Dutson in litt. 2021).
There are no data on population trends. Remote sensed data on tree cover loss indicates that forest loss within the species's range has been very slow over recent decades, with approximately 0.36% of tree cover with at least 50% canopy cover lost over 19 years from 2000-2019 (Global Forest Watch 2021). Hunting may be causing a population decline, but the impact is unknown.
Ducula bakeri is endemic to Vanuatu, where it occurs on eight of the larger northern islands: Ureparapara, Vanua Lava and Gaua (formerly known as Santa Maria) (all in the Banks group), Espiritu Santo, Maewo, Aoba (=Ambae), Pentecost and Ambrym (Diamond and Marshall 1977, Bregulla 1992). Maewo, Pentecost and Ambrym have only small areas of montane forest and this species is found only on the peaks (S. Totterman in litt. 2007).
It occurs in primary montane forests, mainly above 500 m (Gibbs et al. 2001), although it has been recorded as low as 200 m on Espiritu Santo (Kratter et al. 2006) and at sea level on Vanua Lava (S. Totterman in litt. 2007, Parr 2007). It has been found at mid elevation levels in disturbed forest, and higher elevations in primary forest (Barré et al. 2006). It is a locally nomadic frugivore.
A significant area of mid-montane forest has been cleared for cultivation, including for kava Piper methysticum, for domestic and export markets (G. Dutson pers. obs. 1998). Pentecost is a big kava producer with a sizeable human population (S. Totterman in litt. 2007). In addition, lowland forest is being degraded by logging and for cattle-ranching and plantations (G. Dutson pers. obs. 1998, in litt. 2021). However, logging has now largely ceased (G. Dutson in litt. 2021), and tree cover loss has been very slow in the species's range since 2000 (Global Forest Watch 2021).
As one of the largest edible birds on Vanuatu, it is a favoured hunting target for hill villagers (Bregulla 1992). However, its montane haunts and wary nature serve to lessen the impact of this threat, and traditional hunting is suspected to be waning in Vanuatu (G. Dutson in litt. 2021).
Conservation Actions Underway
It is protected by law and may be hunted only between 1 April and 30 June.
40 cm. Large, maroon and grey imperial-pigeon. Upperparts dark grey with paler blue-grey head. Neck and breast purplish-maroon, becoming chestnut on belly. In flight, chestnut underwing-coverts contrast against paler flight feathers. Similar spp. Pacific Imperial-pigeon D. pacifica has swollen black cere, paler grey head and underparts, chestnut only on vent and green-glossed dark grey upperparts. White-throated Pigeon Columba vitiensis has white throat-patch and green iridescence on otherwise black plumage. Voice Two to five deep booms. Hints Call is loud, far-carrying and unmistakeable. Look over mid-montane forest from vantage points. Usually seen singly or in pairs but groups of up to six have been seen in a fruiting tree.
Text account compilers
Diamond, J.M., Dutson, G., Toone, W.D., Totterman, S., O'Brien, M., Mahood, S., Ekstrom, J., Derhé, M., North, A. & Brusland, S.
BirdLife International (2023) Species factsheet: Ducula bakeri. Downloaded from http://datazone.birdlife.org/species/factsheet/vanuatu-imperial-pigeon-ducula-bakeri on 11/12/2023.
Recommended citation for factsheets for more than one species: BirdLife International (2023) IUCN Red List for birds. Downloaded from http://datazone.birdlife.org on 11/12/2023.