Red-billed Helmetshrike

The only batis on Bioko. Patterned like a typical batis, with a white belly and throat, black wings with a white bar, and a black face. Males have a black crown, a black back, and a black chest band, whereas females have a gray crown, a gray back, and a rusty chest band. Both sexes have limited white above the eye that can appear like a broken eyeline. Infrequently encountered but widespread from lowland forest to mid-montane forest, where it can be seen in forest and disturbed forest, including plantations. Songs include a series of high-pitched whistled notes, and a few harsh notes followed by a fast trill that descends slightly in pitch. 

Taxonomically unusual though not very boldly marked warbler. In poor light, or at a distance, looks dingy overall. A good look reveals a brown-olive back, and underparts that are heavily marked with fine barring. Found in thick understory tangles in montane forest of the Albertine Rift. Usually detected by its odd voice: a high, short, rising trill which sounds more like an insect than a bird. Most likely to be confused with Green-backed Camaroptera, but is larger, has a dark rather than red eye, and has fine barring below.

A slim, medium-sized drongo with bright red eyes and gray plumage that is almost black in the western parts of its range and quite pale in the eastern parts of its range; eastern birds also often have an oval-shaped pale facial patch. It has a long slim tail with a deep fork. Common in wooded habitats where it sallies for insects and aggressively chases other birds that may compete for food or nectar. Most birds migrate south every winter. Similar to Black Drongo, but slimmer and usually in different habitats. Calls include harsh and sweet notes, and can mimic some bird species poorly.