• Summary
• Text account
• Data table and detailed info
• Distribution map
• Reference and further resources

Justification of Red List category
This bulbul qualifies as Vulnerable, as it has undergone a rapid decline as a result of hybridisation with spreading Chinese Bulbul populations. Declines have been further compounded by habitat loss.

Population justification
The global population has been estimated at c.10,000-100,000 breeding pairs (Brazil 2009). It is precautionarily placed in the band 10,000-19,999 mature individuals. This equates to 15,000-29,999 individuals in total, rounded here to 15,000-30,000 individuals.

Trend justification
Hybridisation with spreading Chinese Bulbul P. sinensis populations was suspected to be on-going and, together with continuing habitat change, is likely to be causing an on-going and rapid population decline in this species. Slowed hybridisation events in recent years may however require further investigation.

Pycnonotus taivanus is endemic to Taiwan, China (BirdLife International 2001). It is found in eastern Taiwan, China in the coastal plains and hills of Haulien county and Taitung county, in the Huatung valley and as far west as Litao and north to Chungta and Hojen, in southern Taiwan, China at Hengchun and Kenting in southern Pingtung county, and as far north as Fangshan and Fengkang on the south-west coast of Taiwan, China. Although it is considered locally very common in parts of its range (Fang Woeihorng in litt. 2012), with recent counts of over 100 at several sites, its population and range are thought to be declining and the genetic purity of several sub-populations is in doubt. Indeed, genetically pure birds may be limited to the coastal mountains and Tungho and Luye in Taitung county.

It occurs in a wide variety of habitats, including secondary forest, scrub, agricultural areas and gardens. Developed areas in coastal lowlands may also be occupied (Fishpool et al. 2020). Large flocks form in autumn and winter, but it is territorial in the breeding season, which lasts from March through to July. Its diet includes fruit, flowers and insects.

The key threat is hybridisation and competition with the closely related Chinese Bulbul P. sinensis, which was spreading as a consequence of habitat alteration and leading to genetic dilution (Gilbert et al. 2012; Fishpool et al. 2020). The ranges of both species increasingly overlap, as both species occur in agricultural habitats, resulting in frequent hybridisation (Fang Woei-Horng in litt. 2007). This process was accelerated by releases of P. sinensis for religious purposes. Releasing of this type has however reduced in recent years leading to fewer hybridisation events (L. L. Severinghaus in litt. 2020). Existing hybrids between P. taivanus and P. sinensis are subsequently showing reduced frequency in morphology relating to the later, albeit this may be due backcrossing and requires further monitoring. Habitat alteration for agriculture and urbanisation additionally threaten the species throughout its range, and extinction has already occurred in Ilan county, where it has been completely replaced by Chinese Bulbul (Fang Woei-Horng in litt. 2007). 

Conservation Actions Underway
It has been legally protected in Taiwan, China since 1995. It is common in Kenting National Park.

Conservation Actions Proposed
Research the distribution and spread of hybrids within the wild population, in order to aid the development of conservation measures. Examine the possibility of establishing a refuge for genetically pure individuals with a buffer zone in which all hybrids and P. sinensis are removed. Carefully examine the feasibility of a captive-breeding programme and, if established, closely monitor and coordinate it. Alert the government and the public of Taiwan, China of the potential for extinction of this species in order to establish support for conservation measures, particularly the maintenance of a refuge, and to discourage further releases of P. sinensis.

18 cm. Green-grey bulbul. Black cap and moustachial stripe. Greyish-white ear-coverts chin and belly, and darker grey breast. Grey rump and green-grey back. Grey upperwing-coverts, primaries and tail broadly fringed yellow-green. Similar spp. Chinese Bulbul P. sinensis has white stripe through eye extending to hind crown. Black cheeks and ear-coverts with white spot on ear-coverts.

Text account compilers
Fernando, E., Everest, J.

Contributors
Benstead, P., Fang, W., Gilroy, J., Severinghaus, L. & Taylor, J.

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Recommended citation
BirdLife International (2024) Species factsheet: Styan's Bulbul Pycnonotus taivanus. Downloaded from https://datazone.birdlife.org/species/factsheet/styans-bulbul-pycnonotus-taivanus on 23/11/2024.
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 23/11/2024.