Avian frugivores play a key role in seed dispersal of many plant species, including invasive alien plants. We assessed the effect of gut passage on the germination of selected invasive alien plant species in South Africa. Fruits of four fleshly-fruited invasive alien plant species: Solanum mauritianum, Cinnamomum camphora, Psidium guajava, and Morus alba, were fed to two species of indigenous turacos, Knysna (Tauraco corythaix) and purple-crested (Gallirex porphyreolophus) turacos, and to invasive roseringed parakeets (Psittacula krameri). Seed retention time was determined as this can influence both seed dispersal and germination success. Germination success of ingested seeds was compared with that of manually de-pulped seeds, as well as to seeds in whole fruit. The germination success of seeds of all the invasive plant species increased significantly after ingestion by both turaco species compared with seeds from whole fruits. Germination success of manually de-pulped seeds did not differ significantly from that of turaco ingested seeds. In contrast, seed passage through the digestive tract of rose-ringed parakeets significantly reduced germination success and viability of ingested invasive plant species. Our results suggest that Knysna and purple-crested turacos are legitimate seed dispersers of fleshy-fruited invasive plants, while rose-ringed parakeets are mainly seed predators. Although seed predation by rose-ringed parakeets negatively affects the reproductive success of these plants, it is unlikely that this will suppress the spread of these invasive alien plants in South Africa as they are already well established. Furthermore, they can facilitate dispersal by seed regurgitation and dropping uneaten fruits away from the parent plant. Similar trends could be expected for indigenous seeds that rose-ringed parakeets feed on and therefore these birds remain a negative influence within invaded ecosystems.

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The Cape Parrot Poicephalus robustus is endemic to South Africa and numbers have reportedly declined since the early 1900s. It is a forest specialist and food nomadic, moving between patches depending on fruit availability. This makes it difficult to estimate numbers accurately and to determine its distribution. The annual Cape Parrot Big Birding Day was initiated in 1998 as a national census to determine a population estimate. Volunteers assist in monitoring and counting the Cape Parrot in the Eastern Cape, KwaZulu-Natal and Limpopo provinces in indigenous forests as well as sites where the parrots are known to feed outside of forests. Here, a summary of 15 years of census data is presented. In all years, with the exception of 2009, less than 1 600 Cape Parrots were recorded in the wild. The census data showed a slight increase in Cape Parrots, although this may be largely explained by an increase in coverage of suitable habitat and stabilisation in the population since 2005. A current distribution map for the Cape Parrot, based on census data, is presented. The distribution remains largely unchanged from that presented in the 1970s. This study highlights the value of public participation in monitoring an Endangered species and the need to conserve the forests where these parrots occur, due to their nomadic feeding behaviour.

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