The Sulphur-bellied Bulbul (Ixos palawanensis) is a songbird

Songbird

A songbird is a bird belonging to the suborder Passeri of the perching birds . Another name that is sometimes seen as scientific or vernacular name is Oscines, from Latin oscen, "a songbird"...

 species

Species

In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...

 in the bulbul

Bulbul

Bulbuls are a family, Pycnonotidae, of medium-sized passerine songbirds. Many forest species are known as greenbuls. The family is distributed across most of Africa and into the Middle East, tropical Asia to Indonesia, and north as far as Japan. A few insular species occur on the tropical islands...

 family

Family (biology)

In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...

 (Pycnonotidae).

It is one of the species of Ixos

Ixos

Ixos is a songbird genus in the bulbul family, Pycnonotidae. It provisionally contains the following species:* Yellowish Bulbul, Ixos everetti* Streaked Bulbul, Ixos malaccensis...

that might warrant inclusion in the genus

Genus

In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 Hypsipetes

Hypsipetes

Hypsipetes is a genus of bulbuls, songbirds in the family Pycnonotidae. Most of its species birds occur in tropical forests around the Indian Ocean. But while the genus is quite diverse in the Madagascar region at the western end of its range it does not reach the African mainland.Most Hypsipetes...

– as long as this is kept separate from Ixos – as it may be a close relative of the Philippine Bulbul

Philippine Bulbul

The Philippine Bulbul is a songbird species in the bulbul family . It is often placed in the genus Ixos, but is better retained in Hypsipetes as long as this is not entirely merged into Ixos, as it is quite closely related to the type species of Hypsipetes, the Black Bulbul The Philippine Bulbul...

 (H. philippinensis), which in turn is closely related to the type species

Type species

In biological nomenclature, a type species is both a concept and a practical system which is used in the classification and nomenclature of animals and plants. The value of a "type species" lies in the fact that it makes clear what is meant by a particular genus name. A type species is the species...

 of Hypsipetes, the Black Bulbul

Black Bulbul

The Black Bulbul , also known as the Himalayan Black Bulbul, Asian Black Bulbul or Square-tailed Bulbul, is a member of the bulbul family of passerine birds. It is found in southern Asia from India east to southern China. It is the type species of the genus Hypsipetes, established by Nicholas...

 (H. leucocephalus).

It is endemic to the Philippines

Philippines

The Philippines , officially known as the Republic of the Philippines , is a country in Southeast Asia in the western Pacific Ocean. To its north across the Luzon Strait lies Taiwan. West across the South China Sea sits Vietnam...

, where its natural habitat

Habitat

* Habitat , a place where a species lives and grows*Human habitat, a place where humans live, work or play** Space habitat, a space station intended as a permanent settlement...

 is subtropical or tropical moist lowland forest

Forest

A forest, also referred to as a wood or the woods, is an area with a high density of trees. As with cities, depending where you are in the world, what is considered a forest may vary significantly in size and have various classification according to how and what of the forest is composed...

s. It is not considered a threatened species

Threatened species

Threatened species are any speciesg animals, plants, fungi, etc.) which are vulnerable to endangerment in the near future.The World Conservation Union is the foremost authority on threatened species, and treats threatened species not as a single category, but as a group of three categories,...

 by the IUCN.