Secretarybird Sagittarius serpentarius Population Trends and Ecology: Insights from South African Citizen Science Data

Data from two long-term citizen science projects were used to examine the status and ecology of a Red List species, the Secretarybird Sagittarius serpentarius (Vulnerable), in South Africa. The first phase of the Southern African Bird Atlas Project operated from 1987 until 1992, and the second phase began in 2007. The Coordinated Avifaunal Roadcounts (CAR) project began in 1993 and by 1998 had expanded to cover much of the south-eastern half of the country. Data submitted up until April 2013 were used. A new method of comparing reporting rates between atlas projects was developed. Changing reporting rates are likely to reflect changes in abundance; in this instance the data suggest that the Secretarybird population decreased across much of South Africa between the two atlas projects, with a widespread important decrease in the Kruger National Park. Habitat data from the CAR project were analysed to gain insight into the ecology of the species. Secretarybirds tended to avoid transformed habitats across much of the area covered by the CAR project. In the winter rainfall region of the Western Cape, which is characterised by heavily transformed fynbos vegetation, at least 50% of Secretarybirds recorded were in transformed environments. This implies that in the Fynbos biome, at least, Secretarybirds have adapted to transformed environments to some degree. However, in the rest of the country it is likely that habitat loss, largely through widespread bush encroachment but also through agriculture, afforestation, and urbanisation, is a major threat to the species. The methods developed here represent a new approach to analysing data from long-term citizen science projects, which can provide important insights into a species’ conservation status and ecology

Epizoochory in Parrots as an Overlooked Yet Widespread Plant–Animal Mutualism

Plant–animal interactions are key to sustaining whole communities and ecosystem function. However, their complexity may limit our understanding of the underlying mechanisms and the species involved. The ecological effects of epizoochory remain little known compared to other seed dispersal mechanisms given the few vectors identified. In addition, epizoochory is mostly considered non-mutualistic since dispersers do not obtain nutritional rewards. Here, we show a widespread but unknown mutualistic interaction between parrots and plants through epizoochory. Combining our observations with photos from web-sources, we recorded nearly 2000 epizoochory events in 48 countries across five continents, involving 116 parrot species and nearly 100 plant species from 35 families, including both native and non-native species. The viscid pulp of fleshy fruits and anemochorous structures facilitate the adherence of tiny seeds (mean 3.7 × 2.56 mm) on the surface of parrots while feeding, allowing the dispersion of these seeds over long distances (mean = 118.5 m). This parrot–plant mutualism could be important in ecosystem functioning across a wide diversity of environments, also facilitating the spread of exotic plants. Future studies should include parrots for a better understanding of plant dispersal processes and for developing effective conservation actions against habitat loss and biological invasions.This research was funded by Severo Ochoa Program (SVP-2014-068732), Action COST “ParrotNet” (ES1304), and Loro Parque Fundación (PP-146-2018-1). E.S.-G. is funded by a Ramón y Cajal contract (RYC-2019-027216I) from the Spanish Ministry of Science and Innovation

Founder populations and the current status of exotic parrots in South Africa

Parrots (families Psittacidae and Cacatuidae) are one of the most threatened taxa of birds, with a combination of threats to wild populations, including capture for the cage bird market, habitat modification and destruction, persecution, disease, and threats from introduced species. As a result of the group’s popularity as a cage bird, and the transport of vast numbers of individuals across the globe (both legally and illegally), the establishment of populations beyond their natural ranges has likely been enhanced. This review reports on c. 30 parrot species that have been observed outside of their natural ranges in South Africa, most likely derived, and supplemented, from both intentional and unintentional releases. Of these, the Rose-ringed Parakeet Psittacula krameri and at least one Agapornis species have become established as breeding wild populations. Like other invasive species they may pose threats to local biodiversity; however, all are strongly associated with major urban centres where significant changes to natural biota have already occurred.Keywords: alien, founder, invasion, parrots, South AfricaOSTRICH 2014, 85(3): 235–24

Book reviewHandbook of the Birds of the World. Volume 13: Penduline-tits to ShrikesBy Josep Del Hoyo, Andrew Elliott and David Christie (2008)

Lynx Edicions, Barcelona, Spain879 pages, 60 colour plates, hardcoverISBN 978-84-96553-45-3. Price €212Ostrich 2009, 80(1): 67–6

Notes on the flowering and pollination of the endemic grassland <i>Aloe reitzii</i> var. <i>reitzii</i> (Asphodelaceae)

Background: Aloe reitzii var. reitzii is a succulent with a restricted distribution in the montane grassland of eastern South Africa. It is a summer (late January–March) flowering succulent that grows on rocky outcrops at 1000 m–1600 m, and the conspicuous inflorescences suggest a pollination system focused towards birds. Objectives: To understand more about the pollination biology of A. reitzii var. reitzii. Methods: Nectar standing crop (flower volume and concentration) and the proportion of plants flowering were recorded. Camera traps and observations were used to record visitors to A. reitzii var. reitzii inflorescences. Results: Nectar volume was 36 μL ± 27 μL per flower (range 6 μL–93 μL; n = 27) and concentration was 16.5% ± 1.7% (range 13.5% – 19.5%). Camera trap observations, where 18.9% of all plants were observed flowering, recorded the three bird species Cape Weaver, Ploceus capensis, Malachite Sunbird, Nectarinia famosa and Greater Double-collared Sunbird, Cinnyris afer (60.4%, 27.1% and 12.5% of plant visits, respectively) visiting inflorescences. Conclusion: Because birds are important pollinators for many Aloe species, it is assumed that the bird species detected visiting A. reitzii var. reitzii are similarly important pollinators. At least 10 invertebrate species and sengi (Elephantulus sp.) were also recorded as visitors to flowers, but they may be less important pollinators than specialist and generalist avian nectarivores. This study provides further insight into the pollination biology of a diverse, and ecologically important, succulent genus in Africa

Grassland bird response to vegetation structural heterogeneity and clearing of invasive bramble

Spatial and temporal patterns of disturbance and the subsequent heterogeneity are critical in maintaining biodiversity within grassland ecosystems. Grassland birds have evolved within this ‘shifting mosaic’ to become reliant on specific habitat  characteristics maintained under varying levels of both natural and anthropogenic disturbance. Unfortunately, grasslands in South Africa have been extensively transformed and remain poorly conserved, threatening grassland avifauna. Mistbelt grassland is a threatened vegetation type endemic to the province of KwaZulu-Natal, of which only 0.3% is formally protected. This study  investigated seasonal and patch type heterogeneity in a Mistbelt grassland avian community by  determining avian community structure and composition in four patch types, i.e. i) untransformed open grassland, ii) burnt grassland, iii) bramble-invaded and, iv) bramble-cleared grassland, during winter and summer. Avian assemblages were significantly different between the different patch types for each season. The  bramble patch type negatively affected grassland bird species diversity. Bramble-cleared  grassland and untransformed grassland had similar vegetation structure and avian communities in the summer, suggesting that the grassland bird community benefitted soon after the clearing of invasive vegetation. This study provides further evidence that bird diversity is enhanced in structurally heterogeneous grassland landscapes. Furthermore, the protection and appropriate  management of privately owned Mistbelt grassland, conserved in the form of rangeland, is an important refuge for threatened and endemic avifauna, such as the globally-threatened blue swallow (Hirundo atrocaerulea) and wattled crane (Bugeranus carunculatus).Key words: grassland birds, bird diversity, disturbance, grassland management, heterogeneity, invasive vegetation