Aggressive interactions by invasive Common Mynas Acridotheres tristis with urban birds in Pretoria, South Africa

Abstract

We conducted transect surveys in urban Pretoria, South Africa, to document interspecific interactions involving the invasive Common Myna Acridotheres tristis and coexisting species. During 90 standardised transect surveys across three suburban sites from April to August 2022 (outside the main breeding season for many bird species), we recorded 36 interspecific interactions between Common Mynas and other birds. Common Mynas were observed chasing or being aggressive towards other birds such as sparrows (Passer diffusus, P. domesticus) and doves (Streptopelia capicola, Spilopelia senegalensis). Of these encounters, 26 (72%, 95% CI: 56–84%) involved aggression, with Common Mynas initiating 86% of aggressive incidents. In most aggressive incidents, the other bird fled; only larger species (Cape Starlings Lamprotornis nitens) successfully retaliated. Such aggression may facilitate the displacement of native and non-native species from feeding sites or nesting areas. These findings provide evidence for interference competition by Common Mynas in South African urban environments and highlight the need for targeted management strategies to protect native bird communities.