A study on the distribution, status and selected aspects of the foraging ecology of B. cafer in Natal, was undertaken from January 1989 to December 1990. A census was initiated to assess the distribution of B. cafer in Natal. 436 sightings were reported from 187 locations. B. cafer occurs throughout Natal, except in the far northwestern regions. A population estimation based on this census suggest that between 300-350 B. cafer individuals exist in Natal, excluding KwaZulu regions. The large area occupied by KwaZulu and the protection of this species by Zulu folk law, suggest that the population may be considerably larger. Selected aspects of the foraging ecology of the two study groups in the Natal midlands were examined, focusing on the role that individuals play in provisioning the nestling, nest bound female and fledgling. B. cafer are predominantly carnivorous. They are able to utilise habitats used for a wide variety of agricultural practices. The major criteria, in terms of habitat selection, being a short (0.5 m) or sparse ground cover. Younger birds were less successful than older individuals at digging and probing for food. Foraging success rate of the juvenile increased from 7.2% prior to nesting, to 51.2% during nesting. The acquisition of foraging skills, particularly digging and probing, takes time and experience. Frogs were the major food item fed to the nestling and nest bound female. The presence of helpers reduced the amount of feeding by parent birds. Helpers in the stainbank group supp plied 25% of food bundles to the nest. The juvenile did not act as a helper. Subadults helped most during the periods when the demand for food delivery to the nest was highest, and at the end of the nesting period. Helpers reduced the amount of time that the dominant female spent away from the nest during incubation and early nestling phase. Once the female left the nest, the male reduced his food delivery rate. An abundance of frogs, close to the nest, enabled a single pair to adequately provision a nestling. The parent birds provisioned the fledgling until the following breeding season. / Thesis (M.Sc.)-University of Natal, 1990.

No abstract available. / Dissertation (MSc (Zoology))--University of Pretoria, 2007. / Zoology and Entomology / unrestricted

Hornbills (Aves: family Bucerotidae) are a charismatic group of Palaeotropical birds recognised for their distinctive morphology (casque) and behaviour (nest-sealing). Hornbill diet, habitat use, distribution and social system display pronounced interspecific variation, and their mutualistic interactions with tropical fruits provide vital ecosystem services. A wide range of species of hornbills across the Afrotropics, Indo-Malaya and Melanesia are of conservation concern. However, the evolutionary history of hornbills remains unclear and there are conflicting hypotheses about their origin, tempo of diversification and biogeography. Despite a comprehensive cladistic analysis of phenotypic data, there are unresolved taxonomic uncertainties within the family, and although a gradual accumulation of molecular data has revealed interesting phylogenetic relationships, methodological limitations, and incomplete sampling, has left gaps and produced incongruent results. Hence the evolutionary framework against which to interpret the diversity of this group is incomplete. The aim of this thesis was to construct a well-resolved molecular phylogeny of hornbills, and to use it to address longstanding questions about the evolution and diversification of these remarkable birds. This thesis presents a broad phylogenetic and biogeographic analysis of the family Bucerotidae, based on a coalescence of molecular methods and comparative analyses, largely using historical samples and recently-developed bioinformatic approaches. I provide the first complete species-level molecular phylogeny of hornbills, derived from nuclear adenylate kinase 1 intron 5 and mitochondrial (mtDNA) cytochrome b genes, and also a comprehensive mtDNA phylogeny covering 98% of the taxa, with extensive sampling of Asian geo-isolates. Using these two phylogenetic trees, I sought to determine the tempo of divergence, trace the evolution of traits, identify ancestral areas and colonisation routes, and also calculate genetic divergence. In this part of the work, I stress the importance of (1) using historical samples, (2) calibrating time-trees with fossil and molecular anchor-points, and (3) the use of a complete tree to test models of diversification and reconstruct ancestral states. My findings confirm the monophyly of Bucerotidae, showing nearly distinct African and Asian lineages, with relatively congruent topologies across different phylogenetic methods and genes. In turn, these gene trees were comparable with previous cladistic analysis based on phenotypic data. As a result, I was able to resolve some taxonomic issues and propose generic changes. Comparative analyses of social behaviour revealed that cooperative breeding is an ancestral trait, and its evolution in hornbills (in contrast with some other taxa) is associated with stable environments in combination with frugivory, territoriality and reduced body size. Analysis of the evolution of diet with diversification showed that the shift to frugivory from faunivorous African ancestors influenced the rapid diversification of Afro-Asian forest hornbills, facilitated by their preference for humid forests and mutualistic interactions with , hornbill-dispersed fruits (HDF). This dispersal of frugivorous lineages via the Palaeotropical Biotic Interchange promoted colonisation of Asia, with Sundaland being the centre of radiation for continental and insular Asian species. The gradual eastward colonisation from India to Melanesia matches palaeo-tectonic events that allowed dispersal across Huxley's, Wallace's and Lydekker's lines, and was congruent with historical biogeography of some HDFs. Finally, I used a combined analysis of genetic divergence and a standard scoring system for phenotypic data of Asian geo-isolates to provide evidence for quantitative delineation of species and propose changes in conservation status. My findings reveal the evolutionary history of horn bills from their emergence in the Late Oligocene from African origins, with a switch to frugivory influencing successful colonisation of hornbills and HDFs in Asian forests, which combined to promote sociality. Overall, this thesis demonstrates that access to novel environments and innovations to ecological niche facilitate rapid diversification in an avian lineage, and that this process is further promoted by the interplay of these birds in complex mutualistic interactions with their food, as well as palaeo-climatic and palaeo-tectonic changes.

Thesis (M. A. (Sociology)) -- University of the North, 2000 / Refer to the document / NRF (National Research Foundation)

The aim of the study was to determine the consequences of elephant (Loxodonta africana) impact on selected nesting sites of avian fauna and other species in the Associated Private Nature Reserves. The study also aimed at answering key questions on how the architecture of trees influence nest site suitability and what landscape features affect nest site location. Furthermore the type of impact that elephants have on specific nesting sites was determined and how this would affect the short term persistence of these trees. The facillitatory role of elephants was examined by looking at the type of impact that produces gum exudants as well as what gum is selected for by primates and whether primary branch breaking may lead to the creation of nesting sites for species such as the southern ground hornbill (Bucorvus leadbeateri). / Environmental Sciences / M. Sc. (Environmental Management)

No description available.

The aim of the study was to determine the consequences of elephant (Loxodonta africana) impact on selected nesting sites of avian fauna and other species in the Associated Private Nature Reserves. The study also aimed at answering key questions on how the architecture of trees influence nest site suitability and what landscape features affect nest site location. Furthermore the type of impact that elephants have on specific nesting sites was determined and how this would affect the short term persistence of these trees. The facillitatory role of elephants was examined by looking at the type of impact that produces gum exudants as well as what gum is selected for by primates and whether primary branch breaking may lead to the creation of nesting sites for species such as the southern ground hornbill (Bucorvus leadbeateri). / Environmental Sciences / M. Sc. (Environmental Management)

The dispersal services of frugivores affect plant community assembly, persistence, and gene flow in the short-term, and in the long-term are critical to ensuring that tropical trees and palms can regenerate in disturbed areas and can migrate amidst climate change. Halmahera is the largest Moluccan island within the Wallacea biodiversity hotspot, yet data on its plant and animal distributions and interactions are almost null. I studied the tropical trees and palms of Halmahera and their seed dispersal dynamics. Chapter I explores the palms of the Moluccan islands through field-, herbarium-, and literature- based studies. The results of herbarium specimen collections are presented within a preliminary list of palms for Halmahera’s Aketajawe-Lolobata National Park, and contextualized in a review of regional palm biogeography. Expanding beyond the study of one plant family, Chapter II compiles and examines all the tree and palm taxa of the Moluccan islands in order to infer seed dispersal syndromes for each taxon, resulting in an analysis of over 900 taxa. Zoochory was found in 93% of plant families, and nearly 30% of endemic taxa rely primarily on dispersal by large-bodied frugivores. The role of a hypothesized keystone disperser (the Papuan hornbill, Rhyticeros plicatus ruficollis) is confirmed experimentally to disperse about 10% of Halmahera’s tropical tree and palm taxa. The final chapter encompasses an ex-situ germination trial and a year-long in-situ experimental study that examines the germination and recruitment of three palm species post-ingestion by Papuan hornbills, in four different habitat types representative of Halmahera’s landscape. Palms dispersed by hornbills into disturbed habitats and primary forests resulted in enhanced recruitment, although results varied by habitat and species. Hornbills aid both in forest conservation and recovery/assembly after disturbance. The results of this dissertation provide a foundation for further ecological studies and for enhanced conservation of Halmahera island.