The distribution and spread of the invasive alien common myna Acridotheres tristis L. (Aves: Sturnidae), in southern Africa

15 April 2008

The common myna is an Asian starling that has become established in many parts of the world outside of its native range due to accidental or deliberate introductions by humans. The South African population of this species originated from captive birds that escaped in Durban in 1902. A century later, the common myna has become abundant throughout much of South Africa and is considered to pose a serious threat to indigenous biodiversity. Preliminary observations suggest that the common myna’s distribution is closely tied to that of humans, but empirical evidence for this hypothesis is lacking. We have investigated the relationships between common myna distribution, human population size and land-transformation values at a quarter degree resolution in South Africa. Common mynas were found more frequently than expected by chance in areas with greater human population numbers and land transformation values. We also investigated the spatial relationship between the bird’s range and the locations of South Africa’s protected areas at the quarter-degree scale. These results indicate that, although there is some overlap, the common myna distribution is not closely tied to the spatial arrangement of protected areas. We discuss the original introduction, establishment and rate of spread of the common myna in South Africa and the neighbouring countries and contrast the current distribution with that presented in The atlas of Southern African Birds. We also discuss the factors that affect the common myna’s success and the consequences that invasion by this species is likely to have, specifically in protected areas.