Straw-headed Bulbul (BirdLife species factsheet) is a Sundaic lowland forest and secondary growth riparian specialist with the unfortunate curse of a golden voice. Currently listed as Vulnerable on the basis that the species is estimated to have undergone population declines of between 30-49% over a ten year period in the past, in the current period and suspected to do so in the future based on a decline in the extent or area of occupancy or in habitat quality, and on actual or potential levels of exploitation.
The species was long ago elevated to the status of one of most desirable songbirds, certainly in Indonesia, and is consistently the most expensive species in the markets (Nash 1993, Shepherd 2006, Harris et al. 2015). The relatively mild degree of habitat specialism of the species actually rendered it highly accessible to trappers, as being tied to watercourses allowed systematic trapping through each watershed (Wells 2007). Straw-headed Bulbul is now targeted wherever it is known to occur. From being common throughout its large range (southernmost Myanmar and Thailand, Peninsular Malaysia, Sumatra, Java and Borneo) in the 1950s it is now considered with some certainty to be extinct in Java, Nias and Sipora and is likely to very close to extinction on Sumatra (Eaton et al. 2015). The species was considered to be Endangered in Peninsular Malaysia in 2007 after suffering a ‘near-total collapse’ (Wells 2007), and on Borneo it is being trapped even in protected areas (including Danum Valley) (Eaton et al. 2015). Very few are thought to persist in Kalimantan and although small numbers are still appearing for sale (at $300+ per bird) it is unclear from whereabouts these birds are sourced, as other species have been observed being transported across the border from Sarawak (Eaton et al. 2015, J. Eaton in litt. 2016).
Of 119 localities mapped for the species in Indonesia in Threatened Birds of Asia (BirdLife International 2001) only 13 have any records after 1980, and then only (very few) records for Kalimantan since 2010, with birds trapped even in very remote areas (e.g. Brickle et al. 2010). The only location throughout the species’ range in which it has increased in recent years is Singapore, a population likely founded through escapes, and even here birds are being targeted (Anon. 2006). Straw-headed Bulbul has been fully legally protected in Malaysia since 2010, and seizures since that time have led to prosecutions and fines for the traders caught (Shepherd et al. 2013). It is listed on Appendix II of CITES. However illegal trade continues and there seems little enforcement in Indonesia, the driver of the trade, where the species is still not legally protected under national law (Shepherd et al. 2013). At present an ‘Association of Straw-headed Bulbul Breeders’ is supplying birds to the market in Indonesia (Jepson et al. 2011), but the effect of this group in the absence of effective enforcement may be to maintain an otherwise uneconomically viable market into which wild-caught birds can continue to be supplied. Chng et al. (2015) found that the average asking price of the 9 individuals in 2014 was $547.
While it is arguable that the global population decline over any 10-year period has exceeded 49% (the high end of Vulnerable) this has continued unrelentingly for several decades to the point of regional extinction in many locations. The most recent population estimate of 10,000-19,999 mature individuals in 2001 (with poor data quality) looks in hindsight to have been an overestimate, considering the species had disappeared from many locations even by that time.
Matters appear now to have proceeded to the point at which the species’ population in the wild is likely to have fallen below <2,500 mature individuals, and the number of mature individuals in each subpopulation may now be fewer than 250. If these statements are correct, the species will qualify as Endangered under criterion C2a(i).
Is there any information that would enable a more precise assessment of the current population size? It is suspected that the species would fall in the band 1,000 to 2,499 individuals, converted to a rounded figure of 600-1,700 mature individuals. This is based on a rough appraisal of the locations with populations currently persisting, primarily large Protected Areas in Malaysia and also the small population on Singapore and adjacent islands.
For the species to be considered Critically Endangered, the global population decline within a ten-year period prior to, including or into the future from now, would need to exceed 80%, or the current number of mature individuals would need to be fewer than 250 coupled with an ongoing decline in excess of 25% in 3 years.
Anon. 2006. Poaching of Straw-headed Bulbul. Bird Ecology Study Group, Nature Society (Singapore). http://besgroup.blogspot.co.uk/2006/10/poaching-of-straw-headed-bulbul.html. Accessed 24th August 2016.
Brickle, N.W., Eaton, J.A. and Rheindt. F. 2010. A rapid bird survey of the Menyapa mountains, East Kalimantan, Indonesia. Forktail 26: 31-41.
Chng, S. C. L., Eaton, J. A., Krishnasamy, K., Shepherd, C. R. & Nijman, V. 2015. In the market for extinction: an inventory of Jakarta’s bird markets. Petaling Jaya, Selangor, Malaysia: TRAFFIC.
Eaton, J.A., Shepherd, C.R., Rheindt, F.E., Harris, J.B.C., van Balen, S. (B.), Wilcove, D.S. and Collar, N.J. 2015. Trade-driven extinctions and near-extinctions of avian taxa in Sundaic Indonesia. Forktail 31: 1-12.
Jepson, P., Ladle, R. J. & Sujatnika (2011) Assessing market-based conservation governance approaches: a socio-economic profile of Indonesian markets for wild birds. Oryx 45: 482–491.
Nash, S.V. 1993. Sold for a Song. The Trade in Southeast Asian Non-CITES Birds. TRAFFIC International, Cambridge, UK.
Shepherd, C. R. 2006. The bird trade in Medan, North Sumatra: an overview. BirdingASIA 5: 16–24.
Shepherd, C. R., Shepherd, L. A. & Foley, K.-E. 2013. Straw-headed Bulbul Pycnonotus zeylanicus: legal protection and enforcement action in Malaysia. BirdingASIA 19: 92–94.
Wells, D. R. 2007. The birds of the Thai-Malay Peninsula, 2. London: Christopher Helm.