Indian Ocean bulbul


 * For the geometer moth genera Hypsipetes and Ypsipetes, see Hydriomena.

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 bulbuls are dark greyish birds with range or red bills and feet. The feathers on toip of the head are slightly elongated and usually black, and can be erected to form a short and wispy crest.

Species, systematics and taxonomy
The following species are provisionally placed here:
 * Visayan Bulbul, Hypsipetes guimarasensis
 * Zamboanga Bulbul, Hypsipetes rufigularis
 * Yellowish Bulbul, Hypsipetes everetti
 * Philippine Bulbul, Hypsipetes philippinus
 * Mindoro Bulbul, Hypsipetes mindorensis
 * Streak-breasted Bulbul, Hypsipetes siquijorensis
 * Brown-eared Bulbul, Hypsipetes amaurotis''
 * Black Bulbul, Hypsipetes leucocephalus (type species)
 * Square-tailed Bulbul, Hypsipetes ganeesa
 * Moheli Bulbul, Hypsipetes moheliensis
 * Seychelles Bulbul, Hypsipetes crassirostris
 * Grand Comoro Bulbul, Hypsipetes parvirostris
 * Reunion Bulbul, Hypsipetes borbonicus
 * Malagasy Bulbul, Hypsipetes madagascariensis
 * Mauritius Bulbul, Hypsipetes olivaceus

Systematics and taxonomy
The Mountain Bulbul and Sunda Bulbul – formerly H. mcclellandii and H. virescens – are provisionally placed in Ixos until the genus limits in bulbuls are firmly established. They are often included in Hypsipetes but this is an old error that was promoted in modern times by the Sibley taxonomy.

In fact, I. virescens is the type species of Ixos, and though some sources advocate a complete merger of the two genera – and even the entire "Hypsipetes group" of bulbuls, which also includes Hemixos, Iole, Microscelis and Tricholestes –, being the oldest genus name Ixos would apply to all of them, rather than Hypsipetes as is often believed. The most drastic course hardly appropriate however, since Alophoixus and Setornis cannot be excluded from the "Hypsipetes group", and an all-out merge would turn the resultant "genus" into an ill-defined "wastebin taxon". The erroneous inclusion of I. virescens in Hypsipetes has caused the Nicobar Bulbul to be listed under its invalid junior synonym H. nicobariensis rather than the valid names H. virescens or I. nicobariensis.

The Philippine Bulbul on the other hand seems to be closer to the Black Bulbul than to the Mountain Bulbul, and may in fact be correctly placed in Hypsipetes; some other species presently placed in Ixos – the Sulphur-bellied Bulbul, Zamboanga Bulbul and Streak-breasted Bulbul (I. palawanensis, I. rufigularis and I. siquijorensis, respectively) – might also belong here. For as it seems, Ixos is paraphyletic with respect to its relatives, and though too few species have been studied, it may well be that like other species of Ixos (but not I. virescens) do belong in Hypsipetes after all. Alternatively, the Streaked Bulbul (I. malaccensis) and perhaps others which seem closer to the Hemixos lineage might be included there or separated as a distinct genus, and Hypsipetes (and probably Microscelis as well) merged with the core of Ixos under the latter name.