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Location Philippines, Region III,Region IV
Central coordinates 121o 22.00' East  14o 51.00' North
IBA criteria A1, A2
Area 50,000 ha
Altitude 0 - 1,448m
Year of IBA assessment 2001

Haribon Foundation

Site description Mt Irid and Mt Angilo are located on the boundaries between the provinces of Bulacan, Quezon and Rizal, about 40 km to the north-east of Metro Manila, in the southern Sierra Madre mountains. Despite the close proximity to the city, there are very few roads into these rugged mountains, and they are sparsely populated. An extensive stand of what appeared to be old growth dipterocarp forest was located there (above 400 m) during a recent forest mapping survey (SOURCE?). Mt Irid rises to 1,448 m and Mt Angilo to 1,315 m, so there must be areas of montane forest around their peaks, but there are also likely to be substantial areas of lowland forest on the slopes.

Key Biodiversity This IBA is virtually unknown ornithologically, although there is an old record of Philippine Eagle near its western boundary. The extensive lowland and montane forests which are reported to remain there could prove to be important for the eagle, and to support populations of many of the other threatened and restricted-range birds of the Luzon Endemic Bird Area. The avifauna could prove to be similar to that of nearby Angat Dam (PH019) and the IBAs further north in the Sierra Madre.

Non-bird biodiversity: No mammal and herpetofaunal surveys have yet been conducted in this IBA.

Populations of IBA trigger species

Species Season Period Population estimate Quality of estimate IBA Criteria IUCN Category
Philippine Eagle Pithecophaga jefferyi resident  2001  present  A1  Critically Endangered 

IBA Monitoring

2015 very high favourable medium
Good - based on reliable and complete / representative data

Agriculture and aquaculture annual & perennial non-timber crops - agro-industry farming happening now majority/most of area/population (50-90%) very rapid to severe deterioration very high
Agriculture and aquaculture annual & perennial non-timber crops - shifting agriculture happening now some of area/population (10-49%) slow but significant deterioration medium
Climate change and severe weather storms and floods happening now whole area/population (>90%) slow but significant deterioration high
Energy production and mining mining and quarrying happening now some of area/population (10-49%) moderate to rapid deterioration high
Human intrusions and disturbance work and other activities happening now small area/few individuals (<10%) slow but significant deterioration low
Natural system modifications dams & water management/use - large dams likely in short term (within 4 years) majority/most of area/population (50-90%) very rapid to severe deterioration high
Transportation and service corridors roads and railroads likely in long term (beyond 4 years) majority/most of area/population (50-90%) very rapid to severe deterioration high

Pithecophaga jefferyi Philippine Eagle 1 1 individuals 100 favourable

Most of site (50-90%) covered (including the most critical parts for important bird species)  A management plan exists but it is out of date or not comprehensive  Substantive conservation measures are being implemented but these are not comprehensive and are limited by resources and capacity  medium 


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

Protection status Not officially protected.

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Recommended citation  BirdLife International (2015) Important Bird and Biodiversity Area factsheet: Mounts Irid-Angilo and Binuang. Downloaded from on 27/11/2015

To provide new information to update this factsheet or to correct any errors, please email BirdLife