Data Zone
Justification of Red List category
Ramphiculu merrilli is listed as Near Threatened under Criteria C1+2a(ii). There is high uncertainty in the species' population size and distribution, and its ability to disperse between suitable habitat patches, though it likely occurs in several isolated and disjunct subpopulations. Although the overall population is potentially below 10,000 individuals, there is only a suspected continuing decline in the number of mature individuals, and the species is consequently listed as Near Threatened.
Population justification
There is little information about the population size of Ramphiculus merrilli. The species has been considered uncommon (Allen 2020), but its elusive nature likely means it often goes undetected (Gibbs et al. 2001) and is potentially more common than previously thought, even in basic forest (Hornskov 1995, Poulson 1995, Gibbs et al. 2001). It is reportedly common throughout Sierra Madre (Poulsen 1995, Española et al. 2013, Baptista et al. 2020), and (at least was) abundant on Patnanungan Island in the Polillo group (Gonzales and Dans 1995, in BirdLife International 2001). The species' status across large areas of Quezon, Camarines and Albay, where it was historically reported, is unknown (Española et al. 2013).
Bird surveys were carried out December 2009 to September 2010, covering 14 sites across Central Luzon, the Cordillera, Sierra Madre, South Luzon, and West Luzon (Española et al. 2013), therefore covering much of the known range of R. merrilli. The species was found in the highest abundance in Sierra Madre across sites in Isabela, Cagayan, and Aurora, and in at least one site in the other regions, though at much lower densities (Española et al. 2013). This study estimated site-specific species densities using distance sampling software (Thomas et al. 2010; see Española et al. [2013] for full methods), and used these to derive population estimates for five protected areas (Española et al. 2013). From this method, a R. merrilli population for Northern Sierra Madre National Park (NSMNP) of 9,194 (4,363-23,104) individuals was provided (Española et al. 2013). Population estimates for each of the remaining protected areas were between 20 and 1,591 individuals (Española et al. 2013). Estimations were not made for Balbalasang-Balbalan National Park or Mount Isarog Natural Park as species observations were too few for a reliable estimate of population size (Española et al. 2013). However, the rarity of the species in these two areas indicates a very low population size. Overall, this study provided a total estimate of only 4,383-24,695 individuals across all protected areas.
Several sites had wide confidence intervals in their density and/or population estimates, and the species' presence in several historical sites is unknown (Española et al. 2013). Along with the low detactability of the species (Gibbs et al. 2001), these uncertainties makes it difficult to provide an overall estimate of the population size. However, the population estimates from the Española et al. (2013) study presumably represent the highest densities of the species for each specific region, as they are in protected areas. The calculated densities for the remaining regions are fairly consistent, ranging from 0.1-1.2 individuals/km2, compared to 3.1 individuals/km2 for Sierra Madre. The next highest population estimate was 234 (35–1,591) individuals in Subic Bay Forest Reserve and Bataan Natural Park combined. Although the species' occupancy and density outside of reserves is uncertain, including across several historically occupied areas, the estimated densities for the smaller reserve areas suggest densities are likely low and occupancy is patchy. An overall population size of 5,000-30,000 mature individuals is therefore estimated.
Trend justification
Within the range of R. merrilli, there has been a c. 5% loss of forest cover over the past three generations (Global Forest Watch 2024, based on data from Hansen et al. [2013] and methods disclosed therein). However, the rate of forest loss alone may underestimate declines, particularly as the species largely occurs in small and isolated populations which are vulnerable to extinction debt (Española et al. 2013). For example, the species has apparently disappeared from areas in the Laguna province (Gonzalez 1995, Española et al. 2013), with degradation from selective logging implicated in the declines (Gonzalez 1995).
Population declines are suspected to be in the range of 5-19%, including cumulative impacts of habitat loss and modification, and hunting (Poulsen 2005, Baptista et al. 2020). In particular, future declines are expected due to the potential for local extinctions in several of the smaller reserves and the projected loss of habitat in Northern Sierra Madre National Park (Snelder et al. 2013).
Ramphiculus merrilli is endemic to Luzon and two of its satellites, Polillo and Catanduanes, Philippines, where it occurs as two subpsecies; faustinoi north of Quirino and nominate merrilli south of Quirino in the mountains of east and south Luzon, including Catanduanes and Polilo (Baptista et al. 2020). The species has been considered uncommon (Allen 2020), but its elusive nature likely means it often goes undetected (Gibbs et al. 2001) and is potentially more common than previously thought (Hornskov 1995, Poulson 1995, Gibbs et al. 2001). It is reportedly common throughout Sierra Madre (Poulsen 1995, Española et al. 2013, Baptista et al. 2020), and abundant on Patnanungan Island in the Polillo group (Gonzales and Dans 1995 in BirdLife International 2001). The species' status across large areas of Quezon, Camarines, and Albay where it was historically reported is unknown (Española et al. 2013).
This species is found in lowland and sub-montane forest, including primary and selectively logged forest up to 1,300 m (Poulsen 1995, Gibbs et al. 2001, Allen 2020). This species is often seen singularly, or in pairs, and is likely more common than reports suggest due to its elusive nature (Hornskov 1995, Poulson 1995, Gibbs et al. 2001). The species is frugivorous, though there is scarce information on its feeding habits (Gibbs et al. 2001, Baptista et al. 2020).
The species is primarily threatened from habitat loss and degradation, and is at greater risk due to potentially small and fragmented populations. Frugivorous species such as R. merrilli are expected to be at greater risk from extinction following habitat loss, with the risk increasing with the degree to which their feeding habits are specialised (Owens and Bennett 2000).
The highest densities of the species occur in Northern Sierra Madre National Park (NSMNP; Española et al. 2013). However, illegal logging is rampant within the park, with subsistence timber harvesting occurring at the forest edges, gradually degrading habitat quality (van der Ploeg 2011). There has been substantial degradation in certain areas of the park (Grantham et al. 2020), particularly east of Ilagan where high degradation has occurred as a result of roads connecting coastal towns. One study in 2010 modelled the potential impacts of habitat loss in combination with climate change for three different scenarios for NSMNP from 2010 to 2040 (Snelder et al. 2013). The 'worst case' scenario in this study assumes agricultural dominance within NSMNP, which is an unlikely scenario that likely results in an overestimation of habitat loss. However, their scenario modelling impacts accounting for road construction inside the park and agricultural dominance outside the park predicts 20% reduction in the species' distribution (according to Maxent distribution modelling) within NSMNP between 2010 and 2040 (Snelder et al. 2013). This study indicates that even in large protected areas, the species is not necessarily shielded from declines, and it may reasonably be expected that the population within NSMNP will undergo continuing declines into the future.
Additionally, the species is suspected to be under threat from hunting (Poulsen 2005, Baptista et al. 2020). There is little published information on the impacts from hunting, but 40% of Philippine birds are hunted for food and/or sport (Española 2013), with fruit-eating birds among the known targets for poachers in southern Luzon (Scheffers et al. 2012). Enforcement and monitoring of hunting and illegal logging is lacking, even in reserves, putting the species at risk even in protected areas (van der Ploeg 2011, Española 2013).
Conservation Actions Underway
None is known, but the species occurs in several protected areas.
Conservation Actions Proposed
Further surveys are required to accurately determine the population size, number of subpopulations, and the distribution of the species particularly outside of protected areas. Research is required on the movement of the species to determine the likelihood of local extinction in small habitat patches. Greater enforcement of laws to prevent illegal logging, especially within protected areas, is critical. Surveys are required to determine the extent to which the species is impacted by hunting, and greater awareness/enforcement if required to prevent impacts from hunting if necessary.
32–33 cm; 263 g. Large fruit-dove; general plumage deep green, shading to pale grey tinged with green on the head, neck and breast; throat whitish; grey of upper breast divided from creamy buff of lower breast and belly by narrow dark green band; flanks green; undertail-coverts and tibial feathers greenish with whitish tips; outer secondaries dark green with pale yellow edges to outer webs, primaries mostly greenish black; a patch on central secondaries formed by hair-like barbs, appearing purplish when viewed from side but bright crimson when viewed frontally; tail dark green with indistinct pale terminal band on outer feathers; underside of tail pale grey; bill red at base, dull yellow at tip; legs dark red. Sexes alike. Race faustinoi differs by having brownish-red patch on crown. Sounds: Advertising call is a series of very burry coos (duration c. 0·5–0·6 seconds, pitch 300–500 Hz) delivered at a rate of c. 1 note per second, e.g. “rrruuh...rrruuh...rrruuh...”.
Text account compilers
Richardson, L.
Contributors
Benstead, P., Mahood, S. & Taylor, J.
Recommended citation
BirdLife International (2024) Species factsheet: Cream-bellied Fruit-dove Ramphiculus merrilli. Downloaded from
https://datazone.birdlife.org/species/factsheet/cream-bellied-fruit-dove-ramphiculus-merrilli on 23/12/2024.
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 23/12/2024.