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

Justification of Red List category
This bulbul qualifies as Endangered because it is predicted to undergo a very rapid population reduction in the immediate future based on the decline observed in the past and a decline in the extent of its remaining forest habitat.

Population justification
The population is estimated to number 2,500-9,999 mature individuals, based on information in BirdLife International (2001). This estimate equates to 3,750-14,999 individuals, rounded here to 3,500-15,000 individuals.

Trend justification
The species may currently be beneftting from forest regeneration on Siquijor, where it lacks competition from other bulbul species (D. Allen in litt. 2012), but rapid habitat loss through logging and conversion to agriculture continues throughout the species's range, suggesting that rapid population declines have taken place, and that these may increase in severity.

Hypsipetes siquijorensis is endemic to the Philippines, where it occurs in three subspecific populations on four widely separated islands: cinereiceps on Tablas and Romblon, siquijorensis on Siquijor and monticola on Cebu (Collar et al. 1999). This fragmented range suggests that it may be an old, relict species. It was formerly common to abundant, but has evidently declined. Fieldwork conducted during the early 1990s only produced records at single sites on Romblon and Tablas, and four sites on Siquijor. However, it was described as numerous wherever suitable habitat remained, and a population of several thousand birds was estimated for Siquijor (Evans et al. 1993). Some surveys on Tablas have revealed that it may remain fairly common in areas that still retain native forest (A. Pierce verbally 2001), but it may be very restricted on this island and Romblon (D. Allen in litt. 2016). Although considered extinct on Cebu for many years it was recently rediscovered at Tabunan (A. Pierce verbally 2001), though remains rare (D. Allen in litt. 2016) and in need of conservation effort.

It inhabits forest, forest edge and secondary growth. It tolerates degraded habitat, but at lower densities, and only when adjacent to forest. I. s. monticola may be restricted to hill forest, as it has never been seen in open habitats.

Despite its tolerance of degraded habitats, deforestation is the principal threat to this species. Interspecific competition with the Philippine Bulbul I. philippinus on Cebu and Yellow-vented Bulbul Pycnonotus goiavier on Cebu and Tablas appears be a problem (D. Allen in litt. 2012), probably exacerbated by habitat fragmentation. In 1992, only a few small tracts of degraded cover remained on Tablas. Siquijor retains only four forest patches totalling less than 8 km², and logging and encroachment continue unabated. Cebu has retained just 0.03% (c.15 km²) of its original cover, and even the most degraded secondary habitats are scarce.The species is likely to be benefitting from large areas of regenerating forest on Siquijor

Conservation Actions Underway
On Siquijor, the remaining four patches of forest are in state-controlled reserves but the protection afforded in real terms is uncertain. On Tablas (in Romblon province), there is one reserve (the Calatrava-San Andres-San Agustin Watershed Forest Reserve) which offers some protection. The species was rediscovered within the tiny Central Cebu National Park which was declared a Strict Protection Zone in 1996. It is also reported to occur at Alcoy in the south of the island. An education video on the birds of Siquijor has been produced (D. Allen in litt. 2012).

Conservation Actions Proposed
On Siquijor, Romblon and Cebu, promote improved management of the existing reserves to prevent further habitat deterioration. Designate further protected areas as appropriate, particularly on Tablas. Promote forest restoration and regeneration on Tablas. On Cebu, investigate the potential for targeted conservation, including captive breeding, of subspecies monticola (I. Sarenas in litt. 2016).

c.22 cm. Long-tailed and rather drab bulbul. Mid-brown head and upperparts, brownish-grey underparts, paler and greyer on throat and upper breast, with rather broad but poorly defined dark brown streaking on breast. Race siquijorensis has conspicuous dark cap, contrasting with rest of upperparts. Race cinereiceps has duller cap which does not contrast strongly with rest of body. Dark brown or blackish bill and legs. Similar spp. Philippine Bulbul Hypsipetes philippinus is larger, and has longer tail and browner, more uniform plumage. Voice The three subspecies differ in many of their vocalisations (A. Pierce verbally 2001). All three have territorial songs consisting of various phrases repeated in rapid 3 second bursts, e.g. for I. s. cinereceps, song described as hi-ho-hi-ghrrek-ghrrreghk-si-rrediyeray!. Other calls include varied, short chee or chree notes, and squeaky toy sounds (A. Pierce verbally 2001). Hints Frequently encountered in vociferous pairs.

Text account compilers
Gilroy, J., Westrip, J., Taylor, J., Benstead, P.

Contributors
Allen, D., Sarenas, I., Hutchinson, R., Pierce, A.

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Recommended citation
BirdLife International (2024) Species factsheet: Streak-breasted Bulbul Hypsipetes siquijorensis. Downloaded from https://datazone.birdlife.org/species/factsheet/streak-breasted-bulbul-hypsipetes-siquijorensis on 22/11/2024.
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 22/11/2024.