Scientific Name: Acerodon jubatus
Species Authority
Intra-specific Authority: (Eschscholtz, 1831)
Common Name/s: English – Golden-capped Fruit Bat, Golden-crowned Flying Fox
Spanish – Zorro Volador Filipino
Synonym/s: Acerodon lucifer
Assessment Information [top]
Red List Category & Criteria: Endangered A2cd ver 3.1
Year Assessed: 2008
Assessor/s Mildenstein, T., Cariño,A., Paul, S., Heaney, L., Alviola, P., Duya, A., Stier, S., Pedregosa, S., Lorica, R., Ingle, N., Balete, D., Garcia, J.J., Gonzalez, J.C., Ong, P., Rosell-Ambal, G. & Tabaranza, B.
Evaluator/s: Hutson, A.M., Racey, P.A. (Chiroptera Red List Authority) & Stuart, S.N. (Global Mammal Assessment Team)
Justification:
Listed as Endangered because of a serious population decline, estimated to be more than 50% over the last three generations (thirty years in total), inferred from observed reduction in the extent of its lowland forest habitat, and due to the effects of hunting.
History: 1996 - Endangered (Groombridge 1994)
1994 - Endangered (Groombridge 1994)
Geographic Range [top]
Range Description: This species is endemic to the Philippines, where it is widespread with the exception of in the Palawan faunal region and on the Batanes and Babuyan island groups (Heaney et al. 1998). It generally occurs at an altitude range of 0-1,100 m asl. It is only found in large roosts with Pteropus vampyrus. P. vampyrus roosts have been, and are often still assumed to have, A. jubatus present, but the presence of A. jubatus at many roosts has not been confirmed. Historic confirmed records exist for the following islands: Basilan, Biliran (forgaging from a roost on Maripipi - Rickart et al. (1993)), Bohol, Bongao, Boracay, Cabo (in Igat Bay, in Zamboanga del Sur Province, off Mindanao), Cebu, Dinagat, Jolo, Leyte, Luzon, Marinduque, Maripipi, Mindanao, Mindoro, Negros, Panay (formerly regarded as Acerdon lucifer, now extinct, though animals from Boracay (not A. lucifer) visit the north of the island to feed), Polillo, Sibutu and Siquijor.
Recent surveys by the Bat Count Project (source Bat Count Project 2002 and 2003 - T.L. Mildenstein, A.B. Cariño and S.C. Stier in litt. 2007 - unless alternative source given) on the presence and absence of A. jubatus at various bat colonies on islands in the Philippines report its presence at the following sites in which it was found roosting together with larger numbers of P. vampyrus: 1) Bohol Island: Raja Sikatuna Protected Landscape, Bilar; 2) Boracay Island: a colony that feeds on nearby Panay; 3) Cebu: a possible roost at Dalaguete (Pangutalan pers. comm. 2006); 4) Leyte: a colony occurs on Mount Pangasugan; 5) Luzon: Subic Forest Watershed Reserve, Subic Bay; Northern Sierra Madre Natural Park, Divilacan; Ilocos Norte province, Pangasinan province, Baler in Aurora province, and Calamba in Laguna province (P. Alviola pers. obs. 2005); and a possible roost on Mount Banahaw (D. Balete pers. obs. 2003); 6) Mindanao: Occidental Mindoro (Bilog na Sapa); Mutia, Calamba and Mount Malindang, Misamis Occidenta (Ramayla pers. obs.); Mount Hamguitan, Eastern Mindanao (D. Balete pers. obs. 2005); Malagos Forest Watershed Reserve, Davao (N.R. Ingle pers. obs. 2004; Gomez in litt. 2007; and Bat Count Project 2002 and 2003); and possible roost sites, where the presence of the species requires confirmation, in: Magum and Mati, Davao Oriental; Malita, Davao del Sur; and Mount Hilong-hilong, in the lowland dipterocarp forest of Cantilan and Carrascal, Surigao del Sur (Gomez in litt. 2007); 7) Mindoro: a roost occurs at Sablayan and possibly on the eastern side of the island (Saulog and Garcia 2005); 8) Negros: Calinawan, Enrique Villanueva and Sibulan, Negros Oriental; Mambukal, Minoyan, Murcia and Mount Patag, Negros Occidental; and a possible roost in the Manlukahoc area (E. Alcala pers. comm. 2006); and 9) Polillo: a roost occurs on privately owned land (Alviola pers. comm. 2006).
The Bat Count Project has surveyed the following colonies of Pteropus vampyrus and did not find any A. jubatus (though it is unclear that the species occurred in any of these roosts historically (T.L. Mildenstein in litt. 2006)): 1) Cebu: Tabunan and Dalaguete; 2) Mindanao: Bongo Island, Maguindanao Province; and Pinol and Maitum, Sarangani Province; 3) Negros Oriental (southeast Negros): Sagay, Vallehermosa and San Jose; and 4) Panay: Batbatan Island and Culasi, Antique Province. The Siquijor populations are possibly extinct (Lepiten 1995); this species has been reported absent from there recently (T.L. Mildenstein and A.B. Cariño in litt. 2007).
Countries: Native:
Philippines
Population [top]
Population: During the late 1800s and early 1900s there were many anecdotal reports of 100,000 bats in presumed mixed species colonies. Although there are a few mixed colonies that number between 10,000 and 30,000 individuals (from Bat Count surveys - T.L. Mildenstein in litt. 2006), generally, recent observations of mixed colonies have reported maximum sizes of 5,000 and fewer individuals, generally, recent observations have been of colonies with a maximum of 5,000 individuals of mixed species, and usually much smaller numbers have been reported (Heaney and Heideman 1987; Heaney and Utzurrum 1991; Mudar and Allen 1986; Rickart et al. 1993; Utzurrum 1992). There are, however, several colonies that exceed 5,000 individuals of mixed species.
Historically, most colonies of large fruit bats have been assumed to include Acerodon jubatus, but the actual presence of A. jubatus in many colonies has not been confirmed. Current surveys have shown that many fruit bat colonies do not have any A. jubatus at all, and when A. jubatus is present, it has only been found in mixed colonies roosts with Pteropus vampyrus (and sometimes also with Pteropus hypomelanus). Since most mixed colonies are known only through observation, it it has not been determined what proportion of animals in these many colonies are A. jubatus (T.L. Mildenstein in litt. 2006). A. jubatus numbers in a current colony are a small proportion of the total colony size, rarely approaching 20% of the individuals in the roost and in most cases around 5% (T.L. Mildenstein in litt. 2006). Based on species composition of sites that are hunted, only 5% of animals are A. jubatus - T.L. Mildenstein and A.B. Cariño in litt. 2007).
This species is known to be forest-dependent (Mildenstein et al. 2005; Stier and Mildenstein 2005), and it has been determined that 90% of the Philippines original old-growth forest cover has been destroyed (Kummer 1992), although roughly 10-15% secondary forest is estimated to remain. Much of this extant forest occurs above 1,000 m asl, where A. jubatus is unlikely to occur. In a mixed roost of A. jubatus and P. vampyrus on Mindanao, A. jubatus was observed in the forest (away from the forest edge), whereas P. vampyrus were at the periphery, and this might reflect a sensitivity of A. jubatus to disturbance (Gomez in litt. 2007).
Work by the Bat Count Project has shown that populations are small and the number of remaining populations is fewer than were thought to exist historically. Bat Count has also shown that the total colony size (for both A. jubatus and P. vampyrus) correlates closely with available natural forest cover within a foraging range of 15 km², indicating roosting populations are habitat-limited (T.L. Mildenstein, S.C. Stier and A.B. Cariño in litt. 2007). Of the 23 roosts sampled by Bat Count, only nine of these were found to contain A. jubatus during several survey days for each roost. For most other roosts surveyed by Bat Count Philippines, the presence of the species was not documented, (and repeat visits are necessary to confirm absence), but it is not known whether A. jubatus occurred in these roosts historically (T.L. Mildenstein, S.C. Stier and A.B. Cariño in litt. 2006).
L. Heaney (pers. comm. 2006) estimates the total population of A. jubatus to be around one or two percent of what it was 200 years ago and that, if current trends continue, no old-growth lowland forest will remain by 2030. Thus, much of the future population trend for this species will depend on: 1) the extent of regenerating secondary forest; and 2) the ability of A jubatus to persist in secondary forest. A rough estimate of the total population of A. jubatus is around 10,000 individuals (and probably no more than 20,000) (T.L. Mildenstein and A.B. Carino in litt. 2007).
Population Trend: Decreasing
Habitat and Ecology [top]
Habitat and Ecology: This is amongst the heaviest of the world's bats at up to 2.6 pounds (1.2 kg). Currently, it is always found roosting with Pteropus vampyrus (and sometimes Pteropus hypomelanus), but it is uncertain if it has always occurred in mixed roosts). It typically roosts in trees, but also in mangroves, usually on small islands (Hoogstraal 1951, Rabor 1986, Heaney et al. 1998). There is generally high roost site fidelity (T.L. Mildenstein pers. comm. 2006), and roost sites are often located on steep slopes and cliff edges in areas that are difficult to access by humans. A. jubatus is commonly found in trees on the periphery of the roost in areas that are less likely to be disturbed (Mildenstein in litt. 2006).
Foraging occurs in primary and high-quality second-growth forest (Stier and Mildenstein 2005, Mildenstein et al. 2005). The species may occasionally leave this type of habitat, using streams where fig trees grow on banks; they rarely forage in orchards on agricultural trees (Mildenstein et al. 2005). On Mindanao, farmers believe that A. jubatus is a pest in fruit orchards, but it is possible that these individuals are misidentified P. vampyrus which are known to use orchards regularly (T.L. Mildenstein in litt. 2007).
In captivity young are produced only once every two years (Cariño 2004). This may not reflect productivity in the wild, which in other species has been found to be quite different to productivity in captivity (T.L. Mildenstein in litt. 2006), and is probably higher in captivity than in the wild.
Systems: Terrestrial
Threats [top]
Major Threat(s): Acerodon jubatus is a known forest specialist (Mildenstein et al. 2005, Stier and Mildenstein 2005) and it has been determined that more than 90% of the Philippines’ original old-growth forest cover has been destroyed (Kummer 1992). The species is threatened by severe habitat loss and hunting throughout its range (including within protected areas). Remaining total forest cover in the Philippines is roughly in the region of 16-20%, possibly slightly higher - including high-elevation mossy forest and secondary forest (L. Heaney in litt. 2007). However, the area of good quality lowland forest, upon which the species depends, is much less than this.
In Samar and Pangasinan (Luzon), open-cast mines are removing forest cover (M. Pedregosa pers. comm. 2006) and in southwestern Negros, a roost of this species occurs in a copper and gold mining claim area (E. Alcala pers. comm. 2006). The roost on Polillo which occurs on privately owned land is also under threat from human disturbance (P. Alviola pers. comm. 2006) and the population on Boracay is threatened by infrastructure development for tourism (M. Lorica pers. comm. 2006).
Many flying fox colonies have moved from their original roosting sites due to hunting pressure (Mildenstein and Cariño in litt. 2007). A colony which may include A. jubatus in Davao Oriental (Mindanao) has transferred from its original roost due to hunting pressure by loggers who take flying foxes for food (information from a guide during an interview by the Philippine Eagle Foundation (Gomez in litt. 2007)).
This species is hunted throughout its range. Three roost sites (Boracay; Subic Bay, Luzon; and Mambukal, Negros) are formally protected from hunting by local government, while at most other roost sites, A. jubatus experiences regular hunting pressure (Mildenstein in litt. 2006). Whether or not the roost site is protected from hunting, a large amount of hunting occurs away from the roosts during night-time foraging, which commonly occurs in unprotected forests kilometres from the roost. Generally A. jubatus looks similar to the species with which it roosts, and hunters are not aware of which species they are taking (T.L. Mildenstein and A.B. Cariño in litt. 2007). Hunters use lines with hooks (D. Balete pers. comm. 2006), shot guns, rifles, and air guns (T.L. Mildenstein and A.B. Cariño in litt. 2007). In Mindanao, Muslim communities are not known to hunt bats and there may be more roosts in this region that do not experience heavy hunting pressure (T.L. Mildenstein, A.B. Cariño and S.C. Stier in litt. 2007), but most of the roosts surveyed in this region are of Pteropus vampyrus only (T.L. Mildenstein, A.B. Cariño and S.C. Stier in litt. 2007).
An ethnobiological survey of wildlife hunters on Negros Island (Cariño et al. 2006) found that from a total of 150 respondents, 20 reported hunting bats and birds using traditional traps, and 60 reported using air guns. Hunting and eating bats as ‘pulutan’ (any snack eaten while consuming alcohol) is enjoyed. Individual bats can be sold on Negros for 15-30 pesos (0.30-0.60US$) depending on seasonal demand for pulutan. In 2004, the species was reported for sale in Davao in Calinan province (Mindanao) (N. Ingle pers. comm. 2004). A. jubatus, along with other species, is reportedly harvested for food from the mixed species roost at the prison at Sablayan (Mindoro) (H. Garcia pers. comm. 2006); this species is also consumed by locals and enters commercial trade. In general, hunters and fruit bat buyers think of A. jubatus as quite odourous compared to P. vampyrus. In Bataan province (Luzon), A. jubatus is not usually sold because of this (T.L. Mildenstein, A.B. Cariño and S.C. Stier in litt. 2007).
International trade data showed that previously thousands of individuals of fruit bats were exported annually (Mickleburgh et al. 1992), but it is not clear that many of these were A. jubatus. In any case, even if this was a threat, because of CITES listing, better enforcement of legislation, and increased efforts by customs in both Guam and the Philippines, international trade in Philippines fruit bats to Guam has now ceased.
Conservation Actions [top]
Conservation Actions: The species is protected under the Philippine Wildlife Act (Republic Act No. 9147, 2001). A. jubatus has been included in Appendix I of CITES since 1995 (the species had previously been included in Appendix II since 1990). Whilst the majority of the species' roosts are within formally designated protected areas, most receive very little protection (T.L. Mildenstein in litt. 2006). Although officially afforded protection against hunting throughout most of its range in the Philippines (N. Ingle pers. comm. 2006), there is little enforcement of the legislation. Three roosts, located on Boracay (off Panay Island), Subic (Luzon), Mambukal (Negros Occidental), are exempt from hunting pressure as much as these lie within popular tourist areas in which hunting is minimal and the bats are often used as an attraction (T.L. Mildenstein pers. comm. 2006). It remains uncertain whether effective enforcement of legislation is occurring at the Davao colony (Mindanao) (A.B. Cariño and N. Ingle pers. comm. 2006). On Boracay, developers have agreed not to build in the vicinity of roosts (Lorica pers. comm. 2006), although, the construction of a road within the roost site might adversely affect them. Community education and awareness efforts are being undertaken at Subic and Calinawan, and these efforts include addressing problems caused by hunting pressure (A.B. Cariño pers. comm. 2006).
There is a need for much great, and more focused, conservation efforts throughout its range, including the establishment and management of protected areas, and the control of hunting. A captive-breeding project is underway, but well-established captive-breeding facilities are needed.
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