Population estimates of non-native rose-ringed parakeets Psittacula krameri (Scopoli, 1769) in the Durban Metropole, KwaZulu-Natal Province, South Africa

Abstract

Rose-ringed parakeets Psittacula krameri are one of the most widely distributed urban avian invader species present in ~ 35 countries with population sizes increasing. These parakeets were introduced to South Africa as part of the pet trade, and feral populations have established in several urban areas since and are of concern. We, therefore, conducted monthly surveys between August 2018 – December 2019 in the greater Durban Metropole, KwaZulu-Natal Province, to determine their population size and roosting sites. In addition, we recorded bird species that communally roosted with rose-ringed parakeets, and tree species characteristics that they used for roosting. We identified five main roost site areas with an overall mean (± SD) monthly population size of 1 783.3 ± 505.2 rose-ringed parakeets. There was an increase in rose-ringed parakeet numbers, particularly in August and December after their breeding. Most rose-ringed parakeets were recorded in the north, with fewer in the south of the metropole; and many were located around shopping centres and parks. A total of seven bird species communally shared roost sites with rose-ringed parakeets, with the non-native common myna Acridotheres tristis being the species that frequently shared roosts with parakeets. Three tree species were used as roosts, with the Natal mahogany Trichilia emetica and the giant palm Raphia australis, so being the preferred roost tree species. The results showed variations in the measured tree traits and the number of individual parakeets roosting per tree species. The population size of non-native rose-ringed parakeets showed persistent growth, and it is, therefore, suggested that control measures for this species are introduced before its population expands further.