Lorinda A. Hart

Species composition, distribution and habitat types of Odonata in the iSimangaliso Wetland Park, KwaZulu-Natal, South Africa and the associated conservation implications.

Maputaland–Pondoland–Albany, South Africa has been identified as a biodiversity hotspot and centre for endemism. Odonata make good indicators of freshwater ecosystem health. Consequently we compiled a list of Odonata species recorded to date in the iSimangaliso Wetland Park. We then detailed important species in terms of endemism, conservation status, and potential as indicator species. Finally, we compared Odonata assemblages of different sites sampled within the park to illustrate habitat importance. Species identified during two formal surveys and incidental observations made during the study period were combined with an existing database to compile an accurate and up to date species list for the iSimangaliso Wetland Park. Data from this study were then analyzed to determine which water bodies had the most similar species composition. The Dragonfly Biotic Index (DBI) value of each study area was also determined. We recorded 68 odonate species in the iSimangaliso Wetland Park, adding 13 species to the Ezemvelo KwaZulu-Natal Wildlife database for the area. This brings the total number of Odonata species for the iSimangaliso Wetland Park to 86. Eight species are red-listed, 12 are restricted in South Africa to the coastal plains of northern KwaZulu-Natal, and the remainder occurs widely across the southern African savanna. Analyses indicate that species odonate assemblages were most similar in water bodies with comparable habitats. iSimangaliso Wetland Park is identified as an important area for Odonata diversity and endemism, a trend also reflected by the DBI values. Shifts in the existing species assemblages would indicate changes within the ecosystem and thus this species account provides necessary baseline data for the area. Species Conservation efforts should thus target water bodies of varying habitat types to protect greater species diversity.

Ingestion by an invasive parakeet species reduces germination success of invasive alien plants relative to ingestion by indigenous turaco species in South Africa

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 rose-ringed 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.

Fifteen years of annual Cape Parrot Poicephalus robustus censuses: current population trends and conservation contributions

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.

Sitting in the sun: Nest microhabitat affects incubation temperatures in seabirds.

During incubation parent birds are committed to a nest site and endure a range of ambient conditions while regulating egg temperatures. Using artificial eggs containing temperature loggers alongside ambient temperature (Ta) controls, incubation profiles were determined for four tropical seabird species at different nest site locations. Camera traps were used for ad-hoc behavioural incubation observations. Eggs experienced a range of temperatures during incubation and varied significantly between species and in some cases between different microhabitats within a species. Such variation has important consequences in the phenotypic expression of both physical and physiological traits of chicks, and ultimately species fitness. Exposed nest sites were more strongly correlated to Tas. Camera traps highlighted different incubation strategies employed by these species that could be related to trade-offs in predator defence, feeding habits, and temperature regulation of eggs. This study provides evidence that species with similar breeding habits could be affected by environmental stressors in similar ways and that the differences shown in nest site selection could negate some of these effects. We propose that habitats providing suitable nest microclimates will become increasingly important for the successful breeding of seabird species, particularly under predicted climate change scenarios.

Hot footing eggs: thermal imaging reveals foot mediated incubation in White-tailed Tropicbirds, Phaethon lepturus

Birds generally incubate eggs by transferring body heat from an exposed abdominal area known as a brood patch. However, there are exceptions to this where some species use foot-mediated incubation. It was previously thought that, although White-tailed Tropicbirds, Phaethon lepturus, lack a brood patch, the heat generated by their feet was too low to incubate their eggs. Using modern thermal imaging techniques, our results indicate the opposite, revealing that tropicbird feet are an important heat source when incubating their eggs.ZusammenfassungEier auf heißen Füßen: Thermographie zeigt die Bedeutung der Füße für das Brüten beim Weißschwanz-TropikvogelPhaeton lepturusÜblicherweise bebrüten Vögel ihre Eier über einen Brutfleck am unteren Bauch. Doch davon gibt es auch Ausnahmen. Einige Arten bebrüten ihre Eier mit den Füßen. Für den Weißschwanz-Tropikvogel Phaeton lepturus, dem ein Brutfleck fehlt, wurde bisher angenommen, dass die über die Füße abgegebene Wärmemenge nicht ausreicht, Eier zu bebrüten. Mithilfe moderner Thermographie können wir aber das Gegenteil zeigen: Die Füße der Tropikvögel sind die wichtigste Wärmequelle bei der Bebrütung ihrer Eier.

Public surveys of rose-ringed parakeets, Psittacula krameri, in the Durban Metropolitan area, South Africa

Globally, the rose-ringed parakeet, Psittacula krameri, is the most invasive parrot species and became established in South Africa in the 1970s. The aim of this survey was to determine the current occurrence and distribution of rose-ringed parakeets in the greater Durban Metropolitan area of eThekwini, by engaging the public. Within the study area, rose-ringed parakeets currently occupy c. 730 km2. They occur along the coast from Umhlanga in the north to Merebank in the south, extending inland to Mt Edgecombe and Pinetown in the west. Four roosts were located in the study area, with one becoming inactive during the study period. Roosts varied in size from c. 20–100 parakeets each. Comparison of SABAP1 and SABAP2 data indicate that populations are also established in Pietermaritzburg, Cape Town, and Steytlerville in the Eastern Cape. Trends from this study indicate that rose-ringed parakeets are expanding their distribution particularly in the Durban Metropolitan area.

Too hot to sleep? Sleep behaviour and surface body temperature of Wahlberg's Epauletted Fruit Bat.

The significance of sleep and factors that affect it have been well documented, however, in light of global climate change the effect of temperature on sleep patterns has only recently gained attention. Unlike many mammals, bats (order: Chiroptera) are nocturnal and little is known about their sleep and the effects of ambient temperature (Ta) on their sleep. Consequently we investigated seasonal temperature effects on sleep behaviour and surface body temperature of free-ranging Wahlberg’s epauletted fruit bat, Epomophorus wahlbergi, at a tree roost. Sleep behaviours of E. wahlbergi were recorded, including: sleep duration and sleep incidences (i.e. one eye open and both eyes closed). Sleep differed significantly across all the individuals in terms of sleep duration and sleep incidences. Individuals generally spent more time awake than sleeping. The percentage of each day bats spent asleep was significantly higher during winter (27.6%), compared with summer (15.6%). In summer, 20.7% of the sleeping bats used one eye open sleep, and this is possibly the first evidence of one-eye-sleep in non-marine mammals. Sleep duration decreased with extreme heat as bats spent significantly more time trying to cool by licking their fur, spreading their wings and panting. Skin temperatures of E. wahlbergi were significantly higher when Ta was ≥35°C and no bats slept at these high temperatures. Consequently extremely hot days negatively impact roosting fruit bats, as they were forced to be awake to cool themselves. This has implications for these bats given predicted climate change scenarios.

Review of documented beak and feather disease virus cases in wild Cape parrots in South Africa during the last 20 years

Worldwide, there is concern about the increased prevalence of infectious diseases and their effects on biodiversity. Increasing changes in the environment, particularly changes in climatic conditions as a consequence of anthropogenic-induced climate change, are some of the factors driving this increased disease prevalence. Vertebrate taxa that appear to be most affected by these diseases are amphibians and birds, though this may be a consequence of research effort. Beak and feather disease virus (BFDV) affecting psittacine bird species is the disease of concern here. Data on BFDV incidence in wild, endangered Cape parrots (Poicephalus robustus) were collected opportunistically from 1992 to 2014. Data show that the disease is prevalent naturally in the wild during extreme climatic events, including drought. This stresses the birds, which may result in the expression of pathological symptoms. Juveniles in particular appear to succumb during times of drought. This has conservation implications with the impacts of extreme climatic events associated with anthropogenic-induced climate change.ZusammenfassungÜbersicht dokumentierter Schnabel- und Federkrankheitsfälle bei wildlebenden Kappapageien in Südafrika in den letzten 20 Jahren Weltweit besteht Besorgnis über die wachsende Verbreitung von Infektionskrankheiten und die Folgen für die Artenvielfalt. Unter anderem treiben zunehmende Veränderungen der Umwelt, besonders der klimatischen Bedingungen infolge anthropogenen Klimawandels, die Verbreitung von Krankheiten voran. Die am meisten von diesen Krankheiten betroffenen Wirbeltiertaxa sind offenbar Amphibien und Vögel, wobei dies auch eine Folge unterschiedlichen Forschungsaufwands sein könnte. Hier betrachten wir den Schnabel- und Federkrankheitsvirus (BFDV), der Papageienvögel befällt. Daten von BFDV-Fällen bei wildlebenden gefährdeten Kappapageien (Poicephalus robustus) wurden von 1992 bis 2014 opportunistisch gesammelt. Diese Daten zeigen, dass die Krankheit im Freiland naturgemäß während extremer Klimaereignisse wie Dürren auftritt. Diese belasten die Vögel, was eine Ausprägung pathologischer Symptome zur Folge haben kann. Offenbar erliegen besonders Jungvögel während Dürreperioden der Krankheit. Dies hat Folgen für den Schutz der Art, im Zusammenhang mit den Auswirkungen extremer Klimaereignisse, die mit anthropogenem Klimawandel in Zusammenhang stehen.

Hunting flight speeds of five southern African raptors

The flight speeds of hunting falconry birds were determined using global positioning system data loggers. Until now, the hunting flight speed of African raptors has not been directly measured. We predicted that hunting flight speeds would differ between species and that flight dynamics, such as altitude, and bird morphology, particularly wing surface area, would influence maximum and mean flight speeds. This study considered five African raptor species, which included two long-wing species, Lanner Falcon Falco biarmicus and Peregrine Falcon F. peregrinus, one short-wing species, Black Sparrowhawk Accipiter melanoleucus, and two broad-wing species, African Hawk-eagle Aquila spilogaster and Jackal Buzzard Buteo rufofuscus. Maximum and mean hunt speeds differed significantly between the long- and short-wing species. There was no difference in acceleration or deceleration rates between these species, but this could be due to small sample sizes. There was a significant positive correlation between maximum hunt speed and maximum flight height for the long-wing species. Maximum and mean flight speeds were significantly negatively correlated with wing area for all five species in this study. However, following phylogenetic correction, no significant relationship between wing area and maximum hunt speeds was found. This study presents baseline data of hunting speeds in African raptors and further highlights the importance of inter-species variation, which can provide accuracy to flight speed models and the understanding of hunting strategies.

Black Sparrowhawk Accipiter melanoleucus breeding behaviour and reproductive success in KwaZulu-Natal, South Africa

Black Sparrowhawk Accipiter melanoleucus breeding behaviour and nest success was determined using camera traps and field observations in KwaZulu-Natal, South Africa. Nest preparation was done predominantly by the male with incubation and brooding largely performed by the female. Brooding duration decreased with chick age, while feeding frequency and duration increased. Similarly, delivery of fresh leaf material to the nest site increased with chick age. Over the 2011 and 2012 breeding seasons respectively 74% and 41% of nests successfully fledged chicks, with the majority of these producing two offspring.