Data Zone
Justification of Red List category
Spectacled Flowerpecker is known from very few records, having only been discovered in 2009, but these records are widely distributed within remaining lowland forest on Borneo. It is not possible to determine the likely population size, with the very infrequent sightings since first publicised even in intensively watched research sites suggesting it could be very rare indeed, but the great spread of records conversely hinting that it may simply be very hard to detect. All records indicate that the species is highly dependent on intact or largely intact forest, which is being lost at a moderately rapid rate such as to be able to infer there is a continuing decline in the number of individuals, even without being able to quantify such a decline. As such, it is plausible that the species could qualify as either Critically Endangered (under criterion C2a(i or ii) should the population be estimated on rates of encounter from known sites), or as plausibly Least Concern if the population were to be suspected to exceed 10,000 mature individuals on the basis that the species is chronically overlooked, and could occur across the full extent of potential habitat remaining at reasonable densities.
With so few records, assessing the species on the basis that there must be many thousands more is unsound, and as such the species is assessed here as Data Deficient. Increasing the certainty with which the population can be estimated would permit the species to be assessed against one of the other Red List Categories. As a Data Deficient species, further prompt research into the status of Spectacled Flowerpecker is required.
Population justification
The population size is unknown. It is suspected that the species could be present at low densities throughout remaining lowland forest on the island of Borneo, however the highly sporadic nature of sightings indicates perhaps that it is nomadic in addition to being difficult to detect (Saucier et al. 2019). With so few records to date, it is difficult to extrapolate that there is a large population, although if further records confirm the persistent presence in multiple, widely spaced areas, a very small population size becomes less likely.
Trend justification
With only a handful of records from scattered locations in lowland Borneo, it is not possible to estimate a population trend. However the species appears to be highly dependent on largely intact lowland forest, supporting a range of mistletoe species (Saucier et al. 2019) and this habitat is being lost at a moderately rapid rate to both clearance for agriculture and to selective logging (Edwards et al. 2009, Saucier et al. 2019). In the vicinity of the sites at which the species has been recorded (Saucier et al. 2019), the rate of forest loss is estimated at a minimum of 7% in the past ten years (Global Forest Watch 2020). From this we can infer that there is a continuing decline in the number of mature individuals, as there is no evidence that the species can persist in heavily logged forest or in plantations (D. Edwards in litt. 2020, Saucier et al. 2019), but it is not possible to infer the rate of decline. If the distribution of mature mistletoe of certain species, likely a scarce resource (Saucier et al. 2019), is the key determinant of the occurrence of the species, then both the potential population and rate of decline will be very different to that predicted from forest loss data (D. Edwards in litt. 2020).
Spectacled Flowerpecker has now been recorded from widely spaced locations in the lowlands of Borneo; in Malaysia at Danum Valley (Edwards et al. 2009) and Maliau Basin (Sykes and Loseby 2015) in Sabah, and in Lanjak Entimau Wildlife Sanctuary, Sarawak (Saucier et al. 2019); in Brunei at Labi Hills Forest Reserve (Sykes and Loseby 2015) and Belalong Canopy Walkway (Ong 2018); and in Indonesia at Bukit Batikap in Central Kalimantan (Boyd et al. 2016).
The sightings to date are all from areas of mature lowland forest between 30-350 m in elevation (Saucier et al. 2019). No sightings have been made in areas with significant deforestation and it is suspected to be absent in heavily selectively-logged forest (Saucier et al. 2019). Typical of the family it is associated with mistletoes, having been observed foraging within several species from at least two families (Saucier et al. 2019). It certainly appears to be difficult to observe, with almost all records coming from locations where the canopy is within viewing range, for example via a canopy walkway (Edwards et al. 2009, Ong 2018) or through a quirk of topography (Saucier et al. 2019).
Breeding biology, phenology and the extent and type of any movements are presently unknown.
Degradation of lowland forest in Borneo through selective logging, and clearance for conversion to agriculture (primarily for oil palm plantations, but also rubber and in places livestock) are the primary, and potentially only threats to the species. However these threats are operating at a significant rate in lowland Borneo and this is only partly captured via remote sensing applications using satellite imagery. With the likely population size and true distribution of the species currently unknown, the impact on the species is also unknown, but is likely to be significant and certain to be negative.
Conservation Actions in place
The records of the species have all come from sites with some degree of formal protected areas status: Danum Valley Protection Forest Reserve; Maliau Basin Protection Forest Reserve, Lanjak-Entimau Wildlife Sanctuary, Sarawak, Labi Hills (Sungai Ingei Conservation) Forest Reserve, Ulu Temborong National Park, and Bukit Batikap Protection Forest.
Conservation Actions needed
Further research is required into the distribution and status of the species. Targeted searches at previous and new sites will help to establish to what extent the species is resident and hence to estimate likely densities, which can then inform the plausible range of the population size.
Without the need to complete this research, it is clear that the retention of Borneo's lowland dipterocarp forest will go a long way to secure the future of the species. There is an urgent need to secure zones of intact forest within which even selective logging is prevented, alongside extractive uses at different intensities. A complementary forest policy between the countries concerned is required, such that no large area becomes devoid of primary lowland forest.
Area-based management plans for protected areas in which the species has been recorded should make explicit mention of the need to retain intact forest below 350 m elevation for this species's persistence.
c. 8.5 cm. Monochrome flowerpecker unlikely to be encountered away from the canopy of tall lowland dipterocarp forest below 350 m above sea level. The white 'spectacles' are distinctive within Dicaeum, and in conjunction with the soft blue grey upperparts, breast and belly sides contrasting against a clean white throat and belly it is unlikely to be mistaken should you be fortunate enough to encounter one. Voice is a fairly typical high-pitched, rising and falling trill of 12-18 rapid notes (Edwards et al. 2009, Saucier et al. 2019).
Text account compilers
Martin, R.
Contributors
Edwards, D.
Recommended citation
BirdLife International (2025) Species factsheet: Spectacled Flowerpecker Dicaeum dayakorum. Downloaded from
https://datazone.birdlife.org/species/factsheet/spectacled-flowerpecker-dicaeum-dayakorum on 03/01/2025.
Recommended citation for factsheets for more than one species: BirdLife International (2025) IUCN Red List for birds. Downloaded from
https://datazone.birdlife.org/species/search on 03/01/2025.