Alien Birds in Sub-Saharan Africa: An Overview

Introduced species may pose one of the biggest threat to the biodiversity conservation. Monitoring their status, distribution and abundance constitute today an important part of ecological and conservation studies throughout the world. In the Afrotropical Region (sub-Saharan Africa) avian introductions attract attention of many researchers, but there is a lack of comprehensive review of this subject on a continental scale. The presented paper constitutes an attempt to overview the status, distribution, threats and control measures of bird introduced in sub-Saharan Africa in the last 200 years. This review lists 150 bird species introduced in sub-Saharan Africa. Only 49 (32.7%) of them have developed viable populations and only 7 (4.7%) became invasive species, namely Passer domesticus, Sturnus vulgaris, Acridotheres tristis, Corvus splendens, Columba livia var. domestica, Psittacula krameria and Pycnonotus jocosus. Data on distribution of most introduced species are provided together with information on the place and year of their first introductions. For Passer domesticus and Columba livia var. domesticus data on population densities are also provided from several southern African towns. The most specious groups of introduced species were parrots (Psittaciformes) comprising 33.3% (including Pisittacidae: 14%, and Psittaculidae: 16%), Anatidae: 11.3%, Phasianidae: 11.3%, and Passeriformes: 29.3%. Most avian introductions in sub-Saharan Africa took place in Southern Africa (mainly Cape Town, Durban and Johannesburg areas) and in Madagascar and surrounding islands (mostly Mauritius, Reunion and Seychelles). Most introduced species which have developed viable populations originate from Afrotropical, Oriental and Palearctic regions (altogether 78%), with only 2% from the New World. The proportions among introduced species which have not established viable populations are quite different: 30% from the New World, and only 56% from the Afrotropical, Oriental and Palearctic regions (Figure 4). Main factors affecting successful avian introductions and introduction pathways have been identified. A review of control measurers undertaken in sub-Saharan Africa (mainly in small oceanic islands) is outlined for the following species: Passer domesticus, Acridotere tristis, Corvus splendens, Pyconotus jocosus, Foudia madagascarensis, Psittacula krameiri and Agapornis roseicollis.