Movement and Home Range of Nile Crocodiles in Ndumo Game Reserve, South Africa

The study of movement patterns and home range is fundamental in understanding the spatial requirements of animals and is important in generating information for the conservation and management of threatened species. Ndumo Game Reserve, in north-eastern KwaZulu-Natal, bordering Mozambique, has the third largest Nile crocodile (Crocodylus niloticus) population in South Africa. Movement patterns of 50 Nile crocodiles with a total length of between 202 cm and 472 cm were followed over a period of 18 months, using mark-resight, radio and satellite telemetry. The duration of radio transmitter attachment (131 ± 11.4 days) was significantly and negatively related to total length and reproductive status. Satellite transmitters failed after an average of 15 ± 12.5 days. Home range was calculated for individuals with 10 or more radio locations, spanning a period of at least 6 months. There was a significant relationship between home range size and total length, with sub-adults (1.5 m – 2.5 m) occupying smaller, more localised home ranges than adults (> 2.5 m). The largest home ranges were for adults (> 2.5 m). Home ranges overlapped extensively, suggesting that territoriality, if present, does not result in spatially discrete home ranges of Nile crocodiles in Ndumo Game Reserve during the dry season. Larger crocodiles moved farther and more frequently than smaller crocodiles. The reserve acts as a winter refuge and spring breeding site for an estimated 846 crocodiles, which also inhabit the Rio Maputo during the summer months. Nile crocodile movement out of the reserve and into the Rio Maputo starts in November and crocodiles return to the reserve as water levels in the floodplain recede in May. Conservation implications: Movement patterns of Nile crocodiles show the important role the reserve plays in the conservation of Nile crocodile populations within the greater Ndumo Game Reserve–Rio Maputo area

Post‑fledging movement and spatial ecology of the endangered Cape Vulture (\u3ci\u3eGyps coprotheres\u3c/i\u3e)

The post-fledging dependence period (PFDP) is one of the most critical stages in the life history of some avian species. Birds are particularly sensitive to mortality during this stage as they must learn essential skills, such as efficient locomotion, proficient food location and predator avoidance. Knowledge of the PFDP would provide valuable information for conservation management of endangered species, many of which experience high juvenile fatality rates. Post-fledging movements of five endangered Cape Vultures were recorded using Global Positioning System/Global System for Mobile communication telemetry in South Africa. Home range sizes, distances travelled from the nest and habitat use were determined over 11 months during the PFDP. Fledglings increased their home range progressively for the first 2 months, then exhibited a rapid increase in home range size associated with dispersal from their natal colony. Maximum net daily distance also rapidly increased following the dispersal period. A preference for protected areas and woody vegetation (representing cliff faces used for roosting) in terms of habitat use for foraging was evident. The knowledge of the movement and habitat use of juvenile Cape Vultures can aid in the effective conservation planning for the species. Conservation programs in identified areas can be focused on power line and wind-farm mitigation, areas of supplementary feeding and anti-poisoning events

Identifying anthropogenic threats to Cape Vultures Gyps coprotheres using community perceptions in communal farmland, Eastern Cape Province, South Africa

Declines in Old World vulture populations have been linked to anthropogenic pressures. To assess these threats, the social dimensions of vulture conservation must be explored. Prior research in Africa focused on commercial farmers’ perceptions of vultures and identified that small stock farmers used poison more than large stock farmers to deter livestock predators. However, the vulnerable Cape Vulture, Gyps coprotheres, breeds throughout communal farmland in the Eastern Cape Province, South Africa. Consequently, community interviews were conducted within the vultures’ foraging range of the Msikaba Cape Vulture colony, separating regions according to the amount of transformed land. Residents in the least transformed land region perceived the smallest reductions in livestock ownership over the past ten years. While residents of the moderately transformed region perceived the greatest reductions in livestock ownership. Livestock carcasses were reported to be available for vultures at ‘informal vulture restaurants’. Arrangement of livestock carcasses was found to be independent of land use; however type of carcass consumed varied. None of the respondents stated they used poison to eliminate livestock predators. More respondents cited illegal poaching of vultures for traditional medicine as a threat. Despite this pressure, the majority stated that vultures benefited the community.No University of Pretoria affiliation in this article.UKZN and ECPTA.http://journals.cambridge.org/action/displayJournal?jid=BCIhb2016Centre for Wildlife Managemen

Foraging range and habitat use by Cape Vulture Gyps coprotheres from the Msikaba colony, Eastern Cape province, South Africa

Despite the extent of subsistence farmland in Africa, little is known about endangered species that persist within them. The Cape Vulture (Gyps coprotheres) is regionally endangered in southern Africa and at least 20% of the population breeds in the subsistence farmland area previously known as the Transkei in the Eastern Cape province of South Africa. To understand their movement ecology, adult Cape Vultures (n = 9) were captured and fitted with global positioning system/global system for mobile transmitters. Minimum convex polygons (MCPs), and 99% and 50% kernel density estimates (KDEs) were calculated for the breeding and nonbreeding seasons of the Cape Vulture. Land use maps were constructed for each 99% KDE and vulture locations were overlaid. During the non-breeding season, ranges were slightly larger (mean [± SE] MCP = 16 887 km2 ± 366 km2) than the breeding season (MCP = 14 707 km2 ± 2155 km2). Breeding and non-breeding season MCPs overlapped by a total of 92%. Kernel density estimates showed seasonal variability. During the breeding season, Cape Vultures used subsistence farmland, natural woodland and protected areas more than expected. In the non-breeding season, vultures used natural woodland and subsistence farmland more than expected, and protected areas less than expected. In both seasons, human-altered landscapes were used less, except for subsistence farmland. CONSERVATION IMPLICATIONS : These results highlight the importance of subsistence farmland to the survival of the Cape Vulture. Efforts should be made to minimise potential threats to vultures in the core areas outlined, through outreach programmes and mitigation measures. The conservation buffer of 40 km around Cape Vulture breeding colonies should be increased to 50 km.The Gay Langmuir bursary, the Rufford Grant, the University of KwaZulu-Natal, and the Eastern Cape Parks and Tourism Agency.http://www.koedoe.co.za/am201

Nest temperature fluctuations in a cavity nester, the southern ground-hornbill

Southern ground-hornbills Bucorvus leadbeateri inhabit savanna and bushveld regions of South Africa. They nest in the austral summer, which coincides with the wet season and hottest daytime temperatures in the region. They are secondary cavity nesters and typically nest in large cavities in trees, cliffs and earth banks, but readily use artificial nest boxes. Southern ground-hornbills are listed as Endangered in South Africa, with reintroductions into suitable areas highlighted as a viable conservation intervention for the species. Nest microclimate, and the possible implications this may have for the breeding biology of southern ground-hornbills, have never been investigated. We used temperature dataloggers to record nest cavity temperature and ambient temperature for one artificial and 11 natural southern ground-hornbill tree cavity nests combined, spanning two breeding seasons. Mean hourly nest temperature, as well as mean minimum and mean maximum nest temperature, differed significantly between southern ground-hornbill nests in both breeding seasons. Mean nest temperature also differed significantly from mean ambient temperature for both seasons. Natural nest cavities provided a buffer against the ambient temperature fluctuations. The artificial nest provided little insulation against temperature extremes, being warmer and cooler than the maximum and minimum local ambient temperatures, respectively. Nest cavity temperature was not found to have an influence on the breeding success of the southern ground-hornbill groups investigated in this study. These results have potentially important implications for southern ground-hornbill conservation and artificial nest design, as they suggest that the birds can tolerate greater nest cavity temperature extremes than previously thought.The Ford Wildlife Foundation and the First Rand Foundation (Project reference : 033391).http://www.elsevier.com/locate/jtherbio2018-05-31hb2017Veterinary Tropical Disease

An impact assessment of alien invasive plants in South Africa generally dispersed by native avian species

Invasive alien plant species have been identified as a major threat to biodiversity and the relationship with native avian dispersers may increase their invasion potential. The impact of invasive plant species needs to be quantified using comparable assessment tools across different habitats and species to allocate limited resources to high-priority species. Here, we used the Generic Impact Scoring System (GISS) to assess the impacts of 16 fleshy-fruited alien invasive plant species in South Africa generally dispersed by native avian species. The results showed that fleshy-fruited invasive species have both environmental and socio-economic impacts. The cumulated impact scores for lantana (Lantana camara) and the tree of heaven (Ailanthus altissima) were the highest, with scores of 42 and 32, respectively. Some species, such as white mulberry (Morus alba), camphor tree (Cinnamomum camphora), American bramble (Rubus cuneifolius) and Brazilian pepper tree (Schinus terebinthifolius), had low overall impact scores of 8, 18, 14 and 16, respectively, but scored the maximum impact of 5 for certain mechanisms. Environmental impacts of fleshy-fruited invasive plant species had a high impact magnitude through effects on the ecosystem and vegetation. Socio-economic impacts were mainly through effects on forest production, agriculture and human health. Species with large crop sizes, small seeds and fruit sizes had higher environmental and socio-economic impact magnitude. The information generated in this study is important for guiding resource allocation and preventing the uncontrolled introduction of invasive species in South Africa. The impact of the fleshy-fruited invasive species transcended sectors and, therefore, effective management of invasive species will require the collaboration of multiple and inter-sectoral stakeholders in South Africa.https://neobiota.pensoft.nethj2022Mammal Research InstituteZoology and Entomolog

Habitat structure and diversity influence the nesting success of an endangered large cavity-nesting bird, the Southern Ground-hornbill

Habitat features can have a profound effect on the nesting success of birds. Savannas are often managed with predators and large herbivores as priority species, with little thought to the many bird species that management decisions could affect. Using a data set spanning seven breeding seasons, we examined how nesting success of Southern Ground-hornbills (SGHs) Bucorvus leadbeateri in the Kruger National Park varied as a result of various environmental and habitat factors within a radius of 3 km surrounding the nest site. Identifying which factors affect nesting success will allow for targeted management efforts to ensure the long-term survival of SGHs both within and outside of protected areas. Habitat structure and diversity of the vegetation surrounding the nest were the most influential factors on SGH nesting success. SGHs require open grassy areas for foraging and areas with large trees for nesting. Savanna habitat drivers such as elephants and fire should be managed to ensure that sufficient large trees are able to establish in the landscape and to control for bush encroachment. This is especially important in areas earmarked for SGH reintroductions. Nest sites of SGHs should be monitored to mitigate any structural changes in the habitat surrounding the nests. Nests should be modified or artificial nest sites provided, where nests have been damaged or lost, to ensure the continued presence of these birds in African savannas. CONSERVATION IMPLICATIONS : Habitat structure and diversity surrounding Southern Groundhornbill nests has a significant impact on their nesting success. This highlights the importance of monitoring vegetation change in savanna habitats where they occur. Management of savanna areas should take factors that influence bush encroachment, such as fire and elephants, into account to ensure the long-term persistence of these birds.The Ford Wildlife Foundation and the First Rand Foundation.http://www.koedoe.co.zaam2018Veterinary Tropical Disease

Blood lead concentrations in free-ranging Nile crocodiles (Crocodylus niloticus) from South Africa

Generally crocodilians have received little attention with regard to the effects of lead toxicity despite their trophic status as apex, generalist predators that utilize both aquatic and terrestrial habitats, thereby exposing them to a potentially wide range of environmental contaminants. During July–October 2010 we collected whole blood from 34 sub-adult and adult free-ranging Nile crocodiles (Crocodylus niloticus) from three separate populations in northeastern South Africa in order to analyze their blood lead concentrations (BPb). Concentrations ranged from below detectability (<3 μg/dL, n = 8) to 960 μg/dL for an adult male at the Lake St Lucia Estuary. Blood lead concentrations averaged 8.15 μg/dL (SD = 7.47) for females and 98.10 μg/dL (SD = 217.42) for males. Eighteen individuals (53 %) had elevated BPbs (≥10 μg/dL). We assessed 12 general linear models using Akaike’s Information Criterion (AIC) and found no significant statistical effects among the parameters of sex, crocodile size and population sampled. On average, crocodiles had higher BPbs at Lake St Lucia than at Ndumo Game Reserve or Kosi Bay, which we attribute to lead sinker ingestion during normal gastrolith acquisition. No clinical effects of lead toxicosis were observed in these crocodiles, even though the highest concentration (960 μg/dL) we report represents the most elevated BPb recorded to date for a free-ranging vertebrate. Although we suggest adult Nile crocodiles are likely tolerant of elevated Pb body burdens, experimental studies on other crocodilian species suggest the BPb levels reported here may have harmful or fatal effects to egg development and hatchling health. In light of recent Nile crocodile nesting declines in South Africa we urge further BPb monitoring and ecotoxicology research on reproductive females and embryos.The Ford Wildlife Foundation and the South African Water Research Commission.http://link.springer.com/journal/106462017-07-31hb2017Paraclinical Science

Causes of admission to a raptor rehabilitation centre and factors that can be used to predict the likelihood of release

Admission records of rescued birds are an important source of information for tracking the prevalence of human‐related threats to wildlife. In this study, we used admission records from January 2015 to December 2016 to review the causes for raptor admissions to a raptor rehabilitation centre in Pietermaritzburg, South Africa, and to determine factors that can be used to predict the outcome of rehabilitation. During the study period, 242 raptors were admitted to the centre, representing 33 species. The major causes of admission were collision‐related injuries (52%), grounded birds (12%) and orphaned chicks (10%). The most common casualties were spotted eagle‐owl Bubo africanus (23%), yellow‐billed kite Milvus migrans aegyptius/parasitus (12%), jackal buzzard Buteo rufofuscus (10%) and western barn owl Tyto alba (10%). The rehabilitation centre had a release rate of 48%. Reason for admission was a significant predictor of the outcome of rehabilitation while other variables were not. Raptors with no severe injuries such as orphaned chicks and grounded birds were more likely to have successful rehabilitation treatment than raptors suffering from collision injuries. Wildlife rehabilitators can use the results of the present study to develop triage guidelines for raptors admitted to rehabilitation centres.National Research Foundation (ZA), Inyuvesi Yakwazulu‐Natali and Hawk Mountain Sanctuary Association.https://wileyonlinelibrary.com/journal/aje2022-02-08hj2021Mammal Research InstituteZoology and Entomolog