Pycnonotus simplex has been split into Cream-vented Bulbul P. simplex and Cream-eyed Bulbul P. pseudosimplex after Shakya et al. (2019) discovered that white-eyed birds on Borneo hitherto considered variants of red-eyed P. simplex are genetically distinct and more closely related to Ashy-fronted Bulbul P. cinereifrons of Palawan, while Bornean P. simplex are sister to white-eyed P. simplex of the Thai-Malay Peninsula. Since they are sympatric with red-eyed birds, white-eyed Bornean birds must constitute a species, P. pseudosimplex.
Apart from the molecular difference the new form differs by its iris colour (score 3), ‘in being yellower on the throat and vent, creating greater contrast with the darker breast and flanks’ (1), and in seemingly small morphometric characters, with a shorter, shallower bill—when data on males (the paper does not discriminate by sex) are compared, P. pseudosimplex has a mean bill depth of 4.06 SD 0.31 (n=7) vs 4.66 SD 0.23 (n=5) resulting in an effect size of ₋2.21 (score 2).
Shakya, S. B., Lim, H. C., Moyle, R. G., Rahman, M. A., Lakim, M., & Sheldon, F. H. 2019. A cryptic new species of bulbul from Borneo. Bulletin of the British Ornithologists’ Club 139(1): 46-55.
|Migratory status||not a migrant||Forest dependency||Medium|
|Land mass type||Average mass||25 g|
|Extent of Occurrence breeding/resident (km2)||4,040,000|
|Number of locations||-|
|Value||Data quality||Derivation||Year of estimate|
|No. of mature individuals||unknown||not applicable||not applicable||0|
|Decline (3 years/1 generation past)||-||-||-|
|Decline (5 years/1 generation past)||-||-||-|
|Decline (10 years/1 generation past)||-||-||-|
|Decline (10 years/3 generation future)||-||-||-|
|Decline (10 years/3 generation past and future)||-||-||-|
|Number of subpopulations||-||-||-|
|Percentage in largest subpopulation||-||-||-|
Population justification: The global population size has not been quantified, but the species is described as fairly common or very common across much of its range (Fishpool and Tobias 2019).
Trend justification: While the population trend has not been assessed directly, the population is thought to be in decline as a result of rapid ongoing deforestation and habitat loss (del Hoyo et al. 2005). Lowland forest has disappeared at a rapid rate in recent decades throughout much of its range, including Sumatra, Java and Borneo (Hansen et al. 2013, Fishpool and Tobias 2019, Global Forest Watch 2019). This species is particularly at risk as a result of its strong reliance on well-developed forest habitats, although its use of foothill and submontane heath-like habitats help to offset the decreasing trend suspected in P. simplex populations (Fishpool and Tobias 2019).
|Thailand||Khao Nor Chuchi|
|Thailand||Hala Sector, Hala-Bala Wildlife Sanctuary and Bang Lang National Park|
|Thailand||Bala Sector, Hala-Bala Wildlife Sanctuary|
|Thailand||Chaloem Pra Kiet (Pa Phru to Daeng)|
|Malaysia||Trus Madi Range|
|Malaysia||Selangor Heritage Park|
|Malaysia||Krau Wildlife Reserve|
|Malaysia||Maliau Basin Conservation Area|
|Malaysia||Pondok Tanjung Forest Reserve|
|Malaysia||South-east Pahang peat swamp forest|
|Malaysia||Tabin Wildlife Reserve|
|Malaysia||Taman Negara National Park|
|Malaysia||Tanjung Datu-Samunsam Protected Area|
|Malaysia||Central Titiwangsa Range|
|Habitat (level 1)||Habitat (level 2)||Importance||Occurrence|
|Artificial/Terrestrial||Subtropical/Tropical Heavily Degraded Former Forest||suitable||resident|
|Forest||Subtropical/Tropical Moist Lowland||major||resident|
|Forest||Subtropical/Tropical Moist Montane||suitable||resident|
|Altitude||0 - 1100 m||Occasional altitudinal limits|
|Threat (level 1)||Threat (level 2)||Impact and Stresses|
|Biological resource use||Logging & wood harvesting - Unintentional effects: (subsistence/small scale) [harvest]||Timing||Scope||Severity||Impact|
|Ongoing||Majority (50-90%)||Slow, Significant Declines||Medium Impact: 6|
|Purpose||Primary form used||Life stage used||Source||Scale||Level||Timing|
|Pets/display animals, horticulture||-||-||International||Non-trivial||Recent|
BirdLife International (2022) Species factsheet: Pycnonotus simplex. Downloaded from http://www.birdlife.org on 26/06/2022. Recommended citation for factsheets for more than one species: BirdLife International (2022) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 26/06/2022.