Tropical Boubou - Range and Ecology

Range and Ecology

The "Tropical Boubou" occurs from about 10° northern latitude south to the Limpopo River in South Africa. In the western part of its range, it is found as a regular breeder from Côte d'Ivoire eastwards to about 5° N; it is not found further south along the Atlantic coast and in the inner Congo Basin, but occurs on the Scarp of Angola. It also does not seem to occur in northern Somalia, eastern Ethiopia and Kenya, and central Tanzania as well as the lower Ruvuma River basin. It is not a migratory bird and only moves around locally. Seasonal movements are known from Kenya, while in Ethiopia they move up the mountains in summer. Vagrants have been recorded from Senegal, and records from The Gambia and Liberia probably are also mostly or all stray birds; a supposed vagrant from Bioko is not anymore believed to have been of this species.

It is not found in decidedly arid regions and dense forests such as the equatorial rain forest, but occurs on mountains up to 3,000 m ASL. It requires dense ground cover, and is found in a variety of forest and forest-edge habitats, including savannah, Miombo woodland and village gardens. In the drier parts of its range, it is generally restricted to riparian forest, though the Somali Boubou also utilizes semiarid shrubland. Typical vegetation in its habitat is characterized by such plants as African Juniper (Juniperus procera), bracken (Pteridium), Rosoideae shrubs or Brachystegia.

The birds defend a breeding territory of 1-3 hectars; outside the breeding season they move about in a larger area (up to 8 hectars) and are more tolerant of conspecifics, sometimes assembling into loose noisy groups. They rarely fly long distances and tend to skulk in the shrubs and low in trees like a coucal (Centropus), or move on the ground interrupted by bouts of wathing where they stand alert, with the tail slightly raised. When alarmed, they will make a slow descending flight, flashing their white rump patches and giving warning calls, before taking cover. As usual for passerine birds, they scratch indirectly (foot-over-wing). Allopreening has been recorded between mates. At least southern birds moult their whole plumage after the breeding season. This species is presumably preyed upon by the usual vertebrate predators of mid-sized birds. A ringed individual nine to ten years old was recorded.

The Tropical Boubou may be common locally, with 100 individuals per square kilometer; in other places only one-third this population density is recorded however. Still, it is not an uncommon bird across its breeding range and the IUCN treats it as a Species of Least Concern. When the species is split up, the Somali Boubou and Dimorphic Boubou, which are found only in a limited area, might warrant uplisting.