Isabela Oriole
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The Isabela oriole (''Oriolus isabellae'') is a species of the oriole family
endemic Endemism is the state of a species being found only in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also foun ...
to
Luzon Luzon ( , ) is the largest and most populous List of islands in the Philippines, island in the Philippines. Located in the northern portion of the List of islands of the Philippines, Philippine archipelago, it is the economic and political ce ...
in the Philippines. It is an oriole identified by its yellowish green plumage and a very large gray bill. This species was presumed to be
extinct Extinction is the termination of an organism by the death of its Endling, last member. A taxon may become Functional extinction, functionally extinct before the death of its last member if it loses the capacity to Reproduction, reproduce and ...
for many years until its rediscovery in December 1993 near
Diffun Diffun, officially the Municipality of Diffun (; ), is a municipality in the province of Quirino, Philippines. According to the 2020 census, it has a population of 56,102 people. Commercial establishments proliferated along the provincial road ...
, Quirino, and in Mansarong in September 1994. Additional sightings were made in San Mariano, Isabela. and
Baggao Baggao, officially the Municipality of Baggao (; ; ), is a municipality in the province of Cagayan, Philippines. According to the 2020 census, it has a population of 87,753 people. Baggao is from Tuguegarao, from Manila, and from Alcala. E ...
,
Cagayan Valley Cagayan Valley (; ), designated as Region II, is an Regions of the Philippines, administrative region in the Philippines. Located in the northeastern section of Luzon, it is composed of five Provinces of the Philippines, Philippine provinces: ...
It It is found in moist lowland forest up to 440 masl. It is critically endangered with estimates of just 50 to 250 mature individuals remaining. It is threatened by habitat loss and hunting.


Description and taxonomy

It is described on
EBird eBird is an online database of bird observations providing scientists, researchers and amateur naturalists with real-time data about bird distribution and abundance. Originally restricted to sightings from the Western Hemisphere, the project e ...
as "A medium-sized bird of lowland forest, including secondary habitats and bamboo in northern Luzon. Yellow underparts blend into olive upperparts. Bill fairly long and silver. Forages for fruit and insects, sometimes in mixed-species flocks. Similar to White-lored Oriole, but slightly larger, with a silver rather than red bill and no white spot in front of the eye. Song consists of a medium-pitched, upslurred whistle, “hoowit!” This species is monotypic. The Isabela oriole is commonly confused with the much more common white-lored orioles and black-naped orioles. It is differentiated by its extremely large bill grey bill, uniform olive-yellow plumage and lack of white on its lores. The Isabela oriole is most closely related to the white-lored oriole. Both species are closely related to the
paraphyletic Paraphyly is a taxonomic term describing a grouping that consists of the grouping's last common ancestor and some but not all of its descendant lineages. The grouping is said to be paraphyletic ''with respect to'' the excluded subgroups. In co ...
Philippine oriole. The Isabela oriole is sometimes considered to form a
superspecies In biology, a species complex is a group of closely related organisms that are so similar in appearance and other features that the boundaries between them are often unclear. The taxa in the complex may be able to hybridize readily with each oth ...
with the dark-throated oriole and the Philippine oriole. Alternate names for the Isabela oriole include the green-lored oriole and olive-lored oriole.


Ecology and behavior

Feeds mostly on fruit but also insects such as larvae and caterpillars. Typically seen alone, in pairs or small groups in the middle storey to the canopy. It is seen in mixed flocks with other birds such as bar-bellied cuckooshrikes, black-and-white trillers, blackish cuckooshrikes and other forest birds. Breeding believed to occur during April to June. In 2022, the first record and photographs of a juvenile were released.


Distribution and habitat

The Isabela oriole is now confined to the lowland forests in the Northern Sierra Madre mountain range in Luzon. It is frequently seen in the canopy and middle storeys of forests and also forest edge or patches up to 440 masl. It has not been recorded in
Bataan Bataan (, , , ; ) , officially the Province of Bataan, is a province in the Central Luzon region of the Philippines. Its capital is the city of Balanga while Mariveles is the largest town in the province. Occupying the entire Bataan Peninsula ...
province since 1947 despite an intensive search done in 2014.


Conservation status

The Isabela oriole has a known population of about 50-250 mature individuals and is assessed as
Critically Endangered An IUCN Red List critically endangered (CR or sometimes CE) species is one that has been categorized by the International Union for Conservation of Nature as facing an extremely high risk of extinction in the wild. As of December 2023, of t ...
based on its extremely small and fragmented population. Organisations such as Buhay-Ilang, ORIS Project and the Mabuwaya Foundation are working to conserve them with educational programs and festivals celebrating this bird. The oriole is now a
Flagship species In conservation biology, a flagship species is a species chosen to raise support for biodiversity conservation in a given place or social context. Definitions have varied, but they have tended to focus on the strategic goals and the socio-economi ...
for the North Sierra Madre National Park. Since 2015, a research and conservation project for the Isabela Oriole has been implemented in
Baggao Baggao, officially the Municipality of Baggao (; ; ), is a municipality in the province of Cagayan, Philippines. According to the 2020 census, it has a population of 87,753 people. Baggao is from Tuguegarao, from Manila, and from Alcala. E ...
by the Mabuwaya Foundation. Information, education and communication, community consultations are held in Baggao with the local government, the
Department of Environment and Natural Resources The Department of Environment and Natural Resources (DENR; ) is the Executive Departments of the Philippines, executive department of the Philippine government responsible for the conservation, management, development, and proper use of the cou ...
and local residents. Plans are underway to declare the oriole site in Baggao a Critical Habitat and to encourage ecotourism. Under the Philippine law RA9147, it is completely illegal to hunt these birds or to capture and keep them as pets. As it is crically endangered species on the Philippine Red List, any violations have harsher punishments including "imprisonment of a minimum of six (6) years and one (1) day to twelve (12) years and/or a fine of One hundred thousand pesos (100,000.00) to One million pesos (1,000,000.00), if inflicted or undertaken against species listed as critical"


References

{{Taxonbar, from=Q1585174 Isabela oriole Birds of Luzon Endemic fauna of the Philippines Critically endangered fauna of Asia Isabela oriole Isabela oriole Endemic birds of the Philippines