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Location Philippines, Region III
Central coordinates 120o 29.00' East  14o 31.00' North
IBA criteria A1, A2
Area 23,688 ha
Altitude 0 - 1,420m
Year of IBA assessment 2001

Haribon Foundation

Site description The Mariveles Mountains are in southern Bataan province, near the entrance to Manila Bay (PH010), and rise steeply from sea level to 1,420 m. An area of forest is shown there on recent forest cover maps, which is reported to include both lowland and montane forest, including mossy forest. This includes old reforestation plantations in the former Lamao Arsenal and old growth forest at the peak of Mt Mariveles.

Key Biodiversity Many of the threatened and restricted-range birds of the Luzon Endemic Bird Areas have been recorded in or near to this IBA, but there is little recent information on their status there. This is the only site in the Philippines where Ijima's Leaf-warbler has been recorded, although this species is difficult to locate and identify and presumably also winters elsewhere in the islands. It is also notable for the records of the highly threatened Isabela Oriole. This species, Luzon Striped-babbler and Furtive Flycatcher appear to have an unusual disjunct distribution, being recorded from the Bataan peninsula and the Sierra Madre in eastern Luzon. However, this may prove to be a result of gaps in the coverage of some other parts of Luzon by ornithologists. A subspecies of Elegant Tit, Parus elegans gilliardi, is only known from the Bataan peninsula.

Non-bird biodiversity: Baseline surveys of the mammals and herpetofauna have yet to be conducted in the area.

Populations of IBA trigger species

Species Season Period Population estimate Quality of estimate IBA Criteria IUCN Category
Nisaetus philippensis resident  2001  present  A1  Not Recognised 
Green Racquet-tail Prioniturus luconensis resident  2001  present  A1  Endangered 
Ceyx melanurus resident  2001  present  A1  Not Recognised 
Isabela Oriole Oriolus isabellae resident  2001  present  A1  Critically Endangered 
Celestial Monarch Hypothymis coelestis resident  2001  present  A1  Vulnerable 
Izu Leaf-warbler Phylloscopus ijimae winter  2001  present  A1  Vulnerable 
Philippine Cockatoo Cacatua haematuropygia resident  2001  present  A1  Critically Endangered 

Protected areas

Protected area Designation Area (ha) Relationship with IBA Overlap with IBA (ha)  
Mariveles Watershed Forest Reserve 321 protected area contained by site 321  


IUCN habitat Habitat detail Extent (% of site)
Forest   major
Artificial - terrestrial   -

Protection status The Mariveles Watershed Forest Reserve was established through R.A. 3092 in July 1996. It is proposed as a Natural Park under the NIPAS.

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Recommended citation  BirdLife International (2016) Important Bird and Biodiversity Area factsheet: Mariveles mountains. Downloaded from on 24/10/2016

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