Data Zone
Justification of Red List category
This species occurs within a restricted elevational band across a very large but disjunct range, much of which is poorly surveyed and difficult to access. Recent records in Central African Republic suggest that the species is likely to occur within a larger area than previously thought and consequently is unlikely to have a small population. While the range is disjunct and perhaps fragmented, it is also large and the Extent of Occurrence greatly exceeds threatened thresholds, and although the Area of Occupancy has not been quantified due to the uncertainty over the proportion of range occupied, the area of known suitable contiguous habitat within suitable elevation with records of the species indicates that this is highly unlikely to approach the threatened thresholds. However, rates of forest cover loss within the mapped range of the species are accelerating and based on the most recent 5-year average and allowing for additional impacts from degradation and fragmentation this is suspected to result in a population reduction between 7 and 19% over the next three generations. It is judged that the species is likely to occur in a significant proportion of the additional suitable area where the occurrence is considered possible, and while a slow to moderate rate of population reduction is suspected, this is not sufficiently rapid to approach threatened thresholds. Consequently White-naped Pigeon is assessed as Least Concern.
Population justification
The global population size has not been quantified, but the species is described as rare (Gibbs et al. 2001). The known occupied range is large, and the recent documentation of the species from the Central African Republic indicates that if searched for it will be found to occupy a proportion of the very large area of habitat between eastern Democratic Republic of Congo and Central African Republic. The uncertainty means the population size cannot be estimated, but this new information suggests it is much larger than previously suspected.
It is assumed to occur in multiple subpopulations based on the large gaps in distribution and lack of evidence for regular long-range dispersal or movement. There is no movement data for the species. The large gap in distribution between the western and eastern parts of the range are assumed to represent separate subpopulations. Further apparent gaps in the distribution in the east indicate there could be further subdivisions, and in the west records come from at least three areas separated by areas of unsuitable habitat below the elevational limit of the species. Hence it is suspected that there are at least two subpopulations, and there may be up to 10, but more information is required to determine the true population structure.
Trend justification
The species is highly forest dependent, although is noted to use coffee-bush habitat adjacent to forest. Over the past three generations between 9.3% (2000 forest cover/30% canopy cover) and 11.9 % (2010 forest cover/75 % canopy cover) of forest cover has been lost from within the known and probable occurrence range of the species (Global Forest Watch 2022, using Hansen et al. [2013] data and methods disclosed therein). This is suspected to be causing a decline in the population size, but the relationship between abundance and forest area is uncertain. The use of modified forest habitat suggests it may have a small degree of tolerance to degradation and fragmentation, hence it is unclear that degradation beyond the rate of forest loss would drive additional declines above the rate of forest loss. Importantly, the recent documentation of the species from the Central African Republic indicates the true range of the species is much larger area. If this possibly extant range is included, the rate of forest cover loss is lower, between 5.3% (2000 forest cover/30% canopy cover) and 9.3% (2000 forest cover/75% canopy cover). No other threats have been reported for this species. As such, the rate of population reduction over the past three generations (12 years) is suspected to have fallen between 5% and 15%.
The rate of forest loss has increased in recent years within both the known and probable range and the possibly extant range (Global Forest Watch 2022, using Hansen et al. [2013] data and methods disclosed therein). Projecting the annual mean rate of forest loss based on the most recent five years over the next three generations gives a range of 11.7% (2000 forest cover/30% canopy cover) and 15.2% (2000 forest cover/75% canopy cover) for the known and probable range, and 7.1% (2000 forest cover/30% canopy cover) and 12.3% (2000 forest cover/75 % canopy cover) including possibly extant range (Global Forest Watch 2022, using Hansen et al. [2013] data and methods disclosed therein). The most rapid mean rate of reduction for a three-generation period that includes the present (2022) spans the years 2018-2030, and reflects that for the future three generations: between 11.8% (2000 forest cover/30% canopy cover) and 15.5% (2000 forest cover/75% canopy cover) for the known and probable range, and 7.0% (2000 forest cover/30% canopy cover) and 12.2% (2000 forest cover/75% canopy cover) including possibly extant range (Global Forest Watch 2022, using Hansen et al. [2013] data and methods disclosed therein). On the same basis as for the past rate of reduction, assuming that additional threats are not operating and that the impact of degradation and fragmentation is unlikely to be large, the population reduction over the future three generations and for the past and future three generations that include the current year is suspected to be between 7% and 19%.
If presence in Gabon (H. Rainey in litt. 2023) is confirmed the overall rate of forest loss within the range will be slightly lower.
Columba albinucha occurs in dense mid-altitude forests and forested slopes in eastern Democratic Republic of Congo (DRC), where it is reported to be locally common, Bangangai Game Reserve in South Sudan (on the border with the DRC; Hillman and Hillman 1986), Bwamba and Kibale in west Uganda (few records), Central African Republic, seemingly regularly encountered in Chinko Nature Reserve (GBIF.org 2022) and may be more widespread, and Cameroon, where it is known from the Rumpi Hills (three records in 1967; Urban et al. 1986), Mt Kupe and the Bakossi Mountains (Williams 1995, Bowden 2001), Santchou Sanctuary south of Dschang (Bowden 2001, Fotso et al. 2001), Mt Manenguba and there are also records from nearby Mt Nlonako (Dowsett-Lemaire and Dowsett 1999, Fotso et al. 2001, eBird 2022). There are also unpublished observations from Gabon, suggesting the range may be larger than documented (H. Rainey in litt. 2023). There are no confirmed records from within Rwanda (Vande Wegh 2018).
The eastern and western populations are separated by more than 1,000 km, though the species may occur further west in Central African Republic, and potentially further east in Cameroon. It has been suggested that the present range may be a relict from previously widespread cooler and wetter conditions (Baptista et al. 2020). The species is generally considered scarce throughout its range (del Hoyo et al. 1997).
The species inhabits dense forest and forested slopes (del Hoyo et al. 1997). Its altitudinal range in Uganda is 700-1,800 m, with upper limits of 1,500 m in DRC and 1,100 m in Cameroon. There do not appear to be any records from below 700 m. It feeds on fruit and berries taken from the canopy or middle levels in the forest, rarely descending to the ground. A bird in breeding condition has been collected in February, and the only recorded nest contained one egg and was found in secondary growth in a forest clearing (del Hoyo et al. 1997).
The species' scarcity, disjunct range and apparent high dependence on intact forest leaves it vulnerable to the effects of habitat loss (Baptista et al. 2020). The main threats to the species are therefore presumed to be forest clearance for small-holder cultivation and grazing and subsistence-level logging. The rate of forest loss within the confirmed range has been moderately rapid and has increased in recent years (Global Forest Watch 2022, using Hansen et al. [2013] data and methods disclosed therein). However, within the elevational range of the species there is a large area of minimally disturbed and apparently suitable habitat within which there has been minimal loss of forest cover.
Conservation Actions Underway
No conservation action is known for this species, but it does occur in a number of protected areas including National Parks in Cameroon, Democratic Republic of Congo and Uganda.
34 cm in length, 280–290 g. A medium sized Columba that is largely dark maroon, with plain wings and a large white rear crown and nape. Lacks the bright yellow orbital ring and feet of the partially sympatric Rameron Pigeon C. arquatrix, white nape distinguishes this from Cameroon Pigeon C. sjostedti with which it co-occurs in Cameroon. Apparently vocalisations are similar to C. arquatrix.
Text account compilers
Martin, R.
Contributors
Westrip, J.R.S. & Rainey, H.
Recommended citation
BirdLife International (2024) Species factsheet: White-naped Pigeon Columba albinucha. Downloaded from
https://datazone.birdlife.org/species/factsheet/white-naped-pigeon-columba-albinucha on 22/11/2024.
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 22/11/2024.