Many nonhuman primates adjust their behavior and thrive in human-altered habitats, including town... more Many nonhuman primates adjust their behavior and thrive in human-altered habitats, including towns and cities. Studying anthropogenic influences from an animal's perspective can increase our understanding of their behavioral flexibility, presenting important information for human-wildlife cohabitation management plans. Currently, research on anthropogenically disturbed wildlife considers either positive or negative aspects of human-wildlife encounters independently, highlighting a need to consider potential interactions between both aspects. Vervet monkeys (Chlorocebus pygerythrus) are a suitable species to address this gap in research as they tolerate urbanization; however, they are understudied in urban landscapes. We conducted this study in KwaZulu-Natal, South Africa, where vervet monkeys are commonly found throughout the anthropogenic landscape. Here we determined, from a monkey's perspective , how the frequency and nature of human-monkey interactions, both positive (human food availability) and negative (human-monkey aggression), affected vervet monkey ranging patterns in an urban environment. We assessed the movement patterns of three groups of urban vervet monkeys over 1 year, analyzing both 95% and 50% kernel density estimates of their home ranges alongside daily path lengths and path sinuosities every month using generalized linear mixed models. Overall, we found that human interactions within the urban landscape affected all measures of ranging to some degree. The core home ranges of vervet monkeys increased with a higher rate of positive human encounters, and their total home range increased with an interaction of both positive and negative human encounters. Furthermore, vervet monkeys were less likely to respond (i.e., increase daily path length or path sinuosity) to human aggression when food rewards were high, suggesting that effective management should focus on reducing human food foraging opportunities. Our results highlight the complex interplay between positive and negative aspects of urban living and provide guidance for managers of human-nonhuman primate interactions.
Of the numerous factors affecting avian metabolic rate, altitude is one of the least studied. We ... more Of the numerous factors affecting avian metabolic rate, altitude is one of the least studied. We used mass-flow respirometry to measure resting metabolic rate (RMR), evaporative water loss (EWL) and respiratory exchange ratio (RER) in two populations of a small (10–12 g) Afrotropical bird, the Cape White-eye (Zosterops virens), in summer and in winter. In total, 51 freshly wild-caught adult Cape White-eyes were measured overnight. Altitude was included as a source of variation in the best approximating models for body mass, whole-animal RMR, RER, whole-animal standard EWL and whole-animal basal EWL. RER was significantly lower in winter, suggesting a greater proportion of lipid oxidation at lower ambient temperatures (T a). Cape White-eyes were 0.8 g heavier at the higher altitude site and 0.5 g heavier in winter, suggesting they may have increased their metabolic machinery to cope with cooler temperatures. EWL was generally significantly lower in winter than in summer, suggesting that birds may increase EWL with increasing T a , as the need for evaporative cooling increases. Our results support the argument that the subtle and complex effects of altitude (and ambient temperature) should be taken into account in studies on avian metabolic rate. What is already known: Of the numerous studies known to affect avian metabolic rate, altitude is one of the least studied. Although trends are not always clear, generally, at higher altitudes, avian metabolic rate increases. What the study adds: There were statistically significant seasonal and altitudinal differences in various physiological parameters of Cape White-eyes. These results highlight the importance of accounting for altitude in studies of avian metabolic rate.
The ability to thermoregulate in reptilians is often through behavioural modification. We investi... more The ability to thermoregulate in reptilians is often through behavioural modification. We investigated body temperature (Tb) patterns during winter in the amphibious Nile crocodile (Crocodylus niloticus) and its relationship to basking behaviour at the St. Lucia Crocodile Centre, St. Lucia, South Africa. It was found that crocodiles had no daily plateaus in Tb but rather continuous oscillations in Tb within a range of mean minimum Tb 18.8–19.6 °C to mean maximum Tb 26.9–29.2 °C. Crocodile Tb increased during the day, usually after 10:00 irrespective of body size. Behavioural data showed that the crocodiles usually left the water to bask around 10:00. It is suggested that basking behaviour is important for elevating Tb rather than attaining a preferred Tb. The increased Tb may allow them to perform optimally when they return to water. The basking occurrence has management implications as it suggests that the best time to conduct aerial censuses of the St. Lucia crocodiles is during winter after 10:00 when most of the individuals are basking and hence most easily seen.
The spotted ground thrush (Zoothera guttata; SGT) is a globally endangered forest specialist whos... more The spotted ground thrush (Zoothera guttata; SGT) is a globally endangered forest specialist whose distribution is poorly understood in the critically endangered Indian Ocean Coastal Belt Forest (IOCBF) biome on the east coast of southern Africa. More than 70% of the IOCBF has been lost to development, resulting in fragmented forest remnants within a mosaic of different land uses. We conducted camera-trap surveys with 5796 trap-days in 82 forest patches of various sizes across a gradient of land-use types in the IOCBF during the winter seasons of 2014–2016 to establish occupancy (W) of SGT. We used occupancy modelling and incorporated forest microhabitat characteristics and surrounding land-use classifications to compare sites and determine SGT distribution across the habitat mosaic. The top model estimated an average W = 0.39 ± 0.09, and detection probability (P) = 0.11 ± 0.03. At the landscape scale, larger, less isolated patches had a higher W of SGT while P decreased with proximity to cultivated land. At the micro-habitat scale, a high percentage of bare ground influenced W positively but P negatively, as did short grass cover. However, short herbaceous cover and high stem density of large (11–15 m) trees influenced P positively. These results detail the influence of landscape-scale factors including forest fragmentation and conversion to agriculture in conjunction with forest microhabitat-scale characteristics, on patch selection and distribution of a cryptic, ground-dwelling species that is both threatened and under-studied. Given its endangered status and dependence on larger and more mature forest patches, SGT may be an effective flagship species for the conservation of threatened IOCBF patches
The Indian Ocean Coastal Belt (IOCB) of South Africa is a natural forest-grassland mosaic, nested... more The Indian Ocean Coastal Belt (IOCB) of South Africa is a natural forest-grassland mosaic, nested within an anthropogenic, mixed land-use matrix. Given the ongoing threat of agricultural expansion and urbanisation, we assessed the value a buffer habitat (dense bush) for conserving forest species. We investigated the influence of microhabitat complexity on mammal communities within and dense bush habitats, using occupancy modelling. We found vertical stratification gradients as observed in studies of tropical forest chronosequence, i.e. increased foliage density in lower habitat layers and decreased foliage density in higher habitat layers for dense bush, and vice versa for forest. Structural composition suggests that dense bush is within a successional stage of secondary forest regeneration. Bushbuck (Tragelaphus scriptus) occupancy was higher in forest than dense bush, while the opposite was true for blue duiker (Philantomba monticola). Large-spotted genet (Genetta tigrina), Cape porcupine (Hystrix africaeaustralis) and marsh mongoose (Atilax paludinosus) occupancy remained constant between habitats. Grey duiker (Sylvicapra grimmia) occupancy varied greatly between dense bush (0.48 ± 0.01) and forest (0.16 ± 0.01). Dense bush appeared to maintain natural forest assemblages, and may play a crucial role in buffering IOBC forest patches, given their highly-restricted distribution. However, dense bush habitats have no protection status, but play a role in the conservation of forest plants and animals. Therefore, we advocate the inclusion of dense bush habitats in conservation networks focused on forests.
• Eagle nest site preferences were examined on a landscape scale. • Nearest neighbour distances w... more • Eagle nest site preferences were examined on a landscape scale. • Nearest neighbour distances were less than in natural landscapes within the Region. • Most nests were in green-space zones near an interface with formal residential areas. • An exotic invasive Eucalyptus tree was the most frequently used nest tree species. a b s t r a c t Globally, dramatic land use change typical of urbanisation negatively affects biodiversity, especially for top predators. The Durban Metropolitan Open Space System (D'MOSS), South Africa, faces the challenge of conserving biodiversity in a regional hotspot in the face of rapid urban growth in one of Africa's major commercial hubs. Consequently, we investigated nest site selection of crowned eagles (Stephanoaetus coronatus) on various spatial scales within this urban mosaic. Unexpectedly the inter-nest distances were small in this human-dominated landscape. However, breeding sites were not evenly distributed through the landscape and were closely associated with natural forest, while nest trees were most frequently in patches of exotic large riverine Sydney blue gum (Eucalyptus saligna, Smith 1797) within the D'MOSS planning zones. Crowned eagles showed a strong tendency to avoid informal settlement areas; however they were tolerant of proximity to established formal settlements and occupied dwellings. Consequently, continued protection of the D'MOSS system, and a considered approach to management of E. saligna are necessary for the persistence of the crowned eagle in this landscape. Future research should focus on food requirements, post-fledging survival, and recruitment to determine which nest sites are most productive and whether this population is acting as a source or a sink.
Nectar composition within a plant pollinator group can be variable, and bird pollinated plants ca... more Nectar composition within a plant pollinator group can be variable, and bird pollinated plants can be segregated into two groups based on their adaptations to either a specialist or an occasional bird pollination system. Specialist nectarivores rely primarily on nectar for their energy requirements, while occasional nectarivores meet their energy requirements from nectar as well as from seeds, fruit and insects. Avian blood plasma glucose concentration (P Glu) is generally high compared with mammals. It is also affected by a range of factors including species, gender, age, ambient temperature, feeding pattern, reproductive status, circadian rhythm and moult status, among others. We examined whether sugar content affected P Glu of two avian nectarivores, a specialist nectarivore the Amethyst Sunbird Chalcomitra amethystina, and an occasional nectarivore the Cape White-eye Zosterops virens, when fed sucrose–hexose sugar solution diets of varying concentrations (5%–35%). Both species regulated P Glu within a range which was affected by sampling time (fed or fasted) and not dietary sugar concentration. The range in mean P Glu was broader in Amethyst Sunbirds (11.52–16.51 mmol/L) compared with Cape White-eyes (14.33–15.85 mmol/L). This suggests that these birds are not constrained by dietary sugar concentration with regard to P Glu regulation, and consequently selective pressure on plants for their nectar characteristics is due to reasons other than glucose regulation.
Birds generally incubate eggs by transferring body heat from an exposed abdominal area known as a... more 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. Zusammenfassung Eier auf heißen Fü ßen: Thermographie zeigt die Bedeutung der Fü ße fü r das Brü ten beim Weißsch-wanz-Tropikvogel Phaeton lepturus U ¨ blicherweise bebrüten Vögel ihre Eier u ¨ber einen Brut-fleck am unteren Bauch. Doch davon gibt es auch Aus-nahmen. Einige Arten bebrüten ihre Eier mit den Füßen. Für den Weißschwanz-Tropikvogel Phaeton lepturus, dem ein Brutfleck fehlt, wurde bisher angenommen, dass die u ¨ber die Füße abgegebene Wärmemenge nicht ausreicht, Eier zu bebrüten. Mithilfe moderner Thermographie können wir aber das Gegenteil zeigen: Die Füße der Tro-pikvögel sind die wichtigste Wärmequelle bei der Bebrü-tung ihrer Eier.
The Indian Ocean Coastal Belt Forest is extremely biodiverse but is threatened by anthropogenic l... more The Indian Ocean Coastal Belt Forest is extremely biodiverse but is threatened by anthropogenic land-use change. In South Africa, remnant forest patches are divided into highly restricted but protected indigenous forest (IF) and abundant but unprotected coastal thicket/dense bush (DB), which likely represents secondary/regenerating IF. We tested the hypothesis that DB had value for conserving forest-dependent avian taxonomic and functional diversity, as (a) DB is situated with in the forest-anthropogenic land-use mosaic and (b) birds maintain diverse ecosystem functions and are sensitive to environmental change given their varied biological traits. We conducted 149 and 112 fixed-radius point-count surveys of avian communities in 99, and 24, patches of DB and IF, respectively, at each location recording microhabitat vegetation structure. We compared vegetation characteristics and taxonomic species richness between vegetation classes, and tested the breadth of functional trait-space and for significant associations with vegetation structures at each survey location, using RLQ analysis. Vegetation classes differed significantly, but floral species overlap and vegetation structures in DB closely resembled regenerating IF habitat. Specialist ground-nesting and insect-gleaning species corresponded to taller, more diverse IF structures. Other biological traits and total species richness overlapped broadly across both classes, but IF had significantly higher mean species richness. Given the relatively high taxonomic and functional diversity of the avian community in the abundant DB, the scarcity of IF, and the proximity of DB to the anthropogenic land-use mosaic, we recommend allocating suitable DB patches to the Protected Area Network, which may simultaneously help preserve avian taxonomic and functional diversity , facilitate colonisation throughout the fragmented landscape and provide ecosystem services to anthropogenic land uses.
The Howard College Campus (HCC) of the University of KwaZulu-Natal, South Africa, is a registered... more The Howard College Campus (HCC) of the University of KwaZulu-Natal, South Africa, is a registered Conservancy and houses the Msinsi Nature Reserve. A resident population of feral cats (Felis catus) resides on campus. There are two opposing views about these animals; one is that, by killing birds, lizards and small mammals, they negatively affect native wildlife, another is that management efforts, such as feeding and sterilization, minimize predation on wildlife and control cat numbers. The outcome of this debate is crucial in developing long-term management goals for the campus Conservancy. This study represents an assessment of stakeholder perceptions regarding the feral cat population. Participants observed feral cats in areas with feeding stations. Feeding was the main activity observed. Feelings towards the cats were generally positive. There was strong opposition to the eradication of the entire population; respondents did not consider feral cats an invasive alien species, rather a benign exotic species. The management implications of these findings are significant and these views should be considered in developing a management strategy. Further research should explore the use of feeding stations and sterilization, but additional research is necessary to determine the impact of feral cats on wildlife in and around the Conservancy.
To prevent the extinction of one of South Africa's rarest and most charismatic birds, the Ca... more To prevent the extinction of one of South Africa's rarest and most charismatic birds, the Cape Parr ot, captive breeding is being undertaken. Aviculturalists, some of whom contribute to the demise of the species, through capture and illegal trade, are making a significant contribution to its survival, through a breeding programme. This is welcome and beneficial. The parr ots already decimated in the wild, have recently been subjected to another threat, in the form of parrot beak and feather disease, which has caused the mortality of most of the birds in captivity. This ...
In Africa, four genera represent the family Psittacidae; of these, the genus Poicephalus Swainson... more In Africa, four genera represent the family Psittacidae; of these, the genus Poicephalus Swainson is endemic and comprises nine species. Three subspecies of the Cape Parrot, Poicephalus robustus (Gmelin), are often recognized. The endangered nominate subspecies, P. r. robustus, inhabits afromontane forest habitats and is endemic to South Africa. Poicephalus r. suahelicus (Reichenow) occurs in low-lying woodland in south-central Africa. The little-known third subspecies, P. r. fuscicollis (Kuhl), historically occurred from ...
Wild parrots represent one of the greatest commercial interests in the legal trade in wild birds.... more Wild parrots represent one of the greatest commercial interests in the legal trade in wild birds. Although it is difficult to quantify, there is a considerable illegal trade in wild parrots. Thirty-six per cent of the world's parrot species are listed by the International Union for the Conservation of Nature as threatened or near threatened, and 55% of these are threatened to some degree by trade. In this paper, we investigate the impact of protection on the number of nests that failed because of nestlings being taken by humans (hereafter nest take) and on nesting success in parrots. We collate data on parrot nest take from published and unpublished studies from Africa, Asia and Australasia, including countries and sites with and without national and local parrot protection measures in place. Nest take was insignificant in Australia, where all studies were from areas with both local and national protection. For less developed countries, levels of nest take were variable between studies, spanning the whole range from 0 to 100%. Protection significantly reduced nest take and correspondingly increased nesting success. Our results corroborate those for the Neotropics; thus, the advantages of protection appear to be independent of geographical location or political and economic conditions. We analysed data on legal trade in wild-caught parrots before and after implementation of the 1992 Wild Bird Conservation Act (which practically eliminated import of parrots to the USA) and found that there was no apparent shift in parrot imports to other global regions from the Neotropics. We suggest that conservation of parrots globally would benefit from similar legislation introduced in other regions, such as the EU (15), which is responsible for more than 60% of global imports of wild parrots.
Abstract: Little is known about snags in South African indigenous forests. Because of their value... more Abstract: Little is known about snags in South African indigenous forests. Because of their value to wildlife, we initiated this study to quantify snag characteristics and dynamics. We also investigated forest structure (woody component and snags) and forest use by avian species of conservation concern. We examined tree species composition, abundance and tree size in eight Afromontane mixed Podocarpus forests in KwaZulu-Natal, South Africa. In addition, we investigated the succession of snags at the level of individual trees. Large ...
Over a 50 year period the Cape White-eye Zosterops pallidus was the 13th most common bird species... more Over a 50 year period the Cape White-eye Zosterops pallidus was the 13th most common bird species ringed in southern Africa (Oschadleus & Underhill 1999). If not for specifically targeted species like European Swallow Hirundo rustica, African Penguin Spheniscus demersus and Redbilled Quelea Quelea quelea, it would possibly rate higher up the list. The Cape White-eye is common in KwaZulu-Natal (KZN)(Maclean 1994; Nuttall 1997), yet little is documented on the timing of breeding, moult and movements in the region. This ...
Abstract: Features of its breeding and feeding biology make the Cape parrot demographically vulne... more Abstract: Features of its breeding and feeding biology make the Cape parrot demographically vulnerable. It occurs in the fragmented fromontane forest in the Eastern Cape and KwaZulu-Natal, South Africa. Population numbers have declined significantly in recent years. Possible factors contributing to this decline include habitat loss, food shortage, the low reproductive rate, human predation and disease. Selective felling of spp., the preferred food tree and nest site species, has caused food shortage and nest site scarcity. ...
Many nonhuman primates adjust their behavior and thrive in human-altered habitats, including town... more Many nonhuman primates adjust their behavior and thrive in human-altered habitats, including towns and cities. Studying anthropogenic influences from an animal's perspective can increase our understanding of their behavioral flexibility, presenting important information for human-wildlife cohabitation management plans. Currently, research on anthropogenically disturbed wildlife considers either positive or negative aspects of human-wildlife encounters independently, highlighting a need to consider potential interactions between both aspects. Vervet monkeys (Chlorocebus pygerythrus) are a suitable species to address this gap in research as they tolerate urbanization; however, they are understudied in urban landscapes. We conducted this study in KwaZulu-Natal, South Africa, where vervet monkeys are commonly found throughout the anthropogenic landscape. Here we determined, from a monkey's perspective , how the frequency and nature of human-monkey interactions, both positive (human food availability) and negative (human-monkey aggression), affected vervet monkey ranging patterns in an urban environment. We assessed the movement patterns of three groups of urban vervet monkeys over 1 year, analyzing both 95% and 50% kernel density estimates of their home ranges alongside daily path lengths and path sinuosities every month using generalized linear mixed models. Overall, we found that human interactions within the urban landscape affected all measures of ranging to some degree. The core home ranges of vervet monkeys increased with a higher rate of positive human encounters, and their total home range increased with an interaction of both positive and negative human encounters. Furthermore, vervet monkeys were less likely to respond (i.e., increase daily path length or path sinuosity) to human aggression when food rewards were high, suggesting that effective management should focus on reducing human food foraging opportunities. Our results highlight the complex interplay between positive and negative aspects of urban living and provide guidance for managers of human-nonhuman primate interactions.
Of the numerous factors affecting avian metabolic rate, altitude is one of the least studied. We ... more Of the numerous factors affecting avian metabolic rate, altitude is one of the least studied. We used mass-flow respirometry to measure resting metabolic rate (RMR), evaporative water loss (EWL) and respiratory exchange ratio (RER) in two populations of a small (10–12 g) Afrotropical bird, the Cape White-eye (Zosterops virens), in summer and in winter. In total, 51 freshly wild-caught adult Cape White-eyes were measured overnight. Altitude was included as a source of variation in the best approximating models for body mass, whole-animal RMR, RER, whole-animal standard EWL and whole-animal basal EWL. RER was significantly lower in winter, suggesting a greater proportion of lipid oxidation at lower ambient temperatures (T a). Cape White-eyes were 0.8 g heavier at the higher altitude site and 0.5 g heavier in winter, suggesting they may have increased their metabolic machinery to cope with cooler temperatures. EWL was generally significantly lower in winter than in summer, suggesting that birds may increase EWL with increasing T a , as the need for evaporative cooling increases. Our results support the argument that the subtle and complex effects of altitude (and ambient temperature) should be taken into account in studies on avian metabolic rate. What is already known: Of the numerous studies known to affect avian metabolic rate, altitude is one of the least studied. Although trends are not always clear, generally, at higher altitudes, avian metabolic rate increases. What the study adds: There were statistically significant seasonal and altitudinal differences in various physiological parameters of Cape White-eyes. These results highlight the importance of accounting for altitude in studies of avian metabolic rate.
The ability to thermoregulate in reptilians is often through behavioural modification. We investi... more The ability to thermoregulate in reptilians is often through behavioural modification. We investigated body temperature (Tb) patterns during winter in the amphibious Nile crocodile (Crocodylus niloticus) and its relationship to basking behaviour at the St. Lucia Crocodile Centre, St. Lucia, South Africa. It was found that crocodiles had no daily plateaus in Tb but rather continuous oscillations in Tb within a range of mean minimum Tb 18.8–19.6 °C to mean maximum Tb 26.9–29.2 °C. Crocodile Tb increased during the day, usually after 10:00 irrespective of body size. Behavioural data showed that the crocodiles usually left the water to bask around 10:00. It is suggested that basking behaviour is important for elevating Tb rather than attaining a preferred Tb. The increased Tb may allow them to perform optimally when they return to water. The basking occurrence has management implications as it suggests that the best time to conduct aerial censuses of the St. Lucia crocodiles is during winter after 10:00 when most of the individuals are basking and hence most easily seen.
The spotted ground thrush (Zoothera guttata; SGT) is a globally endangered forest specialist whos... more The spotted ground thrush (Zoothera guttata; SGT) is a globally endangered forest specialist whose distribution is poorly understood in the critically endangered Indian Ocean Coastal Belt Forest (IOCBF) biome on the east coast of southern Africa. More than 70% of the IOCBF has been lost to development, resulting in fragmented forest remnants within a mosaic of different land uses. We conducted camera-trap surveys with 5796 trap-days in 82 forest patches of various sizes across a gradient of land-use types in the IOCBF during the winter seasons of 2014–2016 to establish occupancy (W) of SGT. We used occupancy modelling and incorporated forest microhabitat characteristics and surrounding land-use classifications to compare sites and determine SGT distribution across the habitat mosaic. The top model estimated an average W = 0.39 ± 0.09, and detection probability (P) = 0.11 ± 0.03. At the landscape scale, larger, less isolated patches had a higher W of SGT while P decreased with proximity to cultivated land. At the micro-habitat scale, a high percentage of bare ground influenced W positively but P negatively, as did short grass cover. However, short herbaceous cover and high stem density of large (11–15 m) trees influenced P positively. These results detail the influence of landscape-scale factors including forest fragmentation and conversion to agriculture in conjunction with forest microhabitat-scale characteristics, on patch selection and distribution of a cryptic, ground-dwelling species that is both threatened and under-studied. Given its endangered status and dependence on larger and more mature forest patches, SGT may be an effective flagship species for the conservation of threatened IOCBF patches
The Indian Ocean Coastal Belt (IOCB) of South Africa is a natural forest-grassland mosaic, nested... more The Indian Ocean Coastal Belt (IOCB) of South Africa is a natural forest-grassland mosaic, nested within an anthropogenic, mixed land-use matrix. Given the ongoing threat of agricultural expansion and urbanisation, we assessed the value a buffer habitat (dense bush) for conserving forest species. We investigated the influence of microhabitat complexity on mammal communities within and dense bush habitats, using occupancy modelling. We found vertical stratification gradients as observed in studies of tropical forest chronosequence, i.e. increased foliage density in lower habitat layers and decreased foliage density in higher habitat layers for dense bush, and vice versa for forest. Structural composition suggests that dense bush is within a successional stage of secondary forest regeneration. Bushbuck (Tragelaphus scriptus) occupancy was higher in forest than dense bush, while the opposite was true for blue duiker (Philantomba monticola). Large-spotted genet (Genetta tigrina), Cape porcupine (Hystrix africaeaustralis) and marsh mongoose (Atilax paludinosus) occupancy remained constant between habitats. Grey duiker (Sylvicapra grimmia) occupancy varied greatly between dense bush (0.48 ± 0.01) and forest (0.16 ± 0.01). Dense bush appeared to maintain natural forest assemblages, and may play a crucial role in buffering IOBC forest patches, given their highly-restricted distribution. However, dense bush habitats have no protection status, but play a role in the conservation of forest plants and animals. Therefore, we advocate the inclusion of dense bush habitats in conservation networks focused on forests.
• Eagle nest site preferences were examined on a landscape scale. • Nearest neighbour distances w... more • Eagle nest site preferences were examined on a landscape scale. • Nearest neighbour distances were less than in natural landscapes within the Region. • Most nests were in green-space zones near an interface with formal residential areas. • An exotic invasive Eucalyptus tree was the most frequently used nest tree species. a b s t r a c t Globally, dramatic land use change typical of urbanisation negatively affects biodiversity, especially for top predators. The Durban Metropolitan Open Space System (D'MOSS), South Africa, faces the challenge of conserving biodiversity in a regional hotspot in the face of rapid urban growth in one of Africa's major commercial hubs. Consequently, we investigated nest site selection of crowned eagles (Stephanoaetus coronatus) on various spatial scales within this urban mosaic. Unexpectedly the inter-nest distances were small in this human-dominated landscape. However, breeding sites were not evenly distributed through the landscape and were closely associated with natural forest, while nest trees were most frequently in patches of exotic large riverine Sydney blue gum (Eucalyptus saligna, Smith 1797) within the D'MOSS planning zones. Crowned eagles showed a strong tendency to avoid informal settlement areas; however they were tolerant of proximity to established formal settlements and occupied dwellings. Consequently, continued protection of the D'MOSS system, and a considered approach to management of E. saligna are necessary for the persistence of the crowned eagle in this landscape. Future research should focus on food requirements, post-fledging survival, and recruitment to determine which nest sites are most productive and whether this population is acting as a source or a sink.
Nectar composition within a plant pollinator group can be variable, and bird pollinated plants ca... more Nectar composition within a plant pollinator group can be variable, and bird pollinated plants can be segregated into two groups based on their adaptations to either a specialist or an occasional bird pollination system. Specialist nectarivores rely primarily on nectar for their energy requirements, while occasional nectarivores meet their energy requirements from nectar as well as from seeds, fruit and insects. Avian blood plasma glucose concentration (P Glu) is generally high compared with mammals. It is also affected by a range of factors including species, gender, age, ambient temperature, feeding pattern, reproductive status, circadian rhythm and moult status, among others. We examined whether sugar content affected P Glu of two avian nectarivores, a specialist nectarivore the Amethyst Sunbird Chalcomitra amethystina, and an occasional nectarivore the Cape White-eye Zosterops virens, when fed sucrose–hexose sugar solution diets of varying concentrations (5%–35%). Both species regulated P Glu within a range which was affected by sampling time (fed or fasted) and not dietary sugar concentration. The range in mean P Glu was broader in Amethyst Sunbirds (11.52–16.51 mmol/L) compared with Cape White-eyes (14.33–15.85 mmol/L). This suggests that these birds are not constrained by dietary sugar concentration with regard to P Glu regulation, and consequently selective pressure on plants for their nectar characteristics is due to reasons other than glucose regulation.
Birds generally incubate eggs by transferring body heat from an exposed abdominal area known as a... more 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. Zusammenfassung Eier auf heißen Fü ßen: Thermographie zeigt die Bedeutung der Fü ße fü r das Brü ten beim Weißsch-wanz-Tropikvogel Phaeton lepturus U ¨ blicherweise bebrüten Vögel ihre Eier u ¨ber einen Brut-fleck am unteren Bauch. Doch davon gibt es auch Aus-nahmen. Einige Arten bebrüten ihre Eier mit den Füßen. Für den Weißschwanz-Tropikvogel Phaeton lepturus, dem ein Brutfleck fehlt, wurde bisher angenommen, dass die u ¨ber die Füße abgegebene Wärmemenge nicht ausreicht, Eier zu bebrüten. Mithilfe moderner Thermographie können wir aber das Gegenteil zeigen: Die Füße der Tro-pikvögel sind die wichtigste Wärmequelle bei der Bebrü-tung ihrer Eier.
The Indian Ocean Coastal Belt Forest is extremely biodiverse but is threatened by anthropogenic l... more The Indian Ocean Coastal Belt Forest is extremely biodiverse but is threatened by anthropogenic land-use change. In South Africa, remnant forest patches are divided into highly restricted but protected indigenous forest (IF) and abundant but unprotected coastal thicket/dense bush (DB), which likely represents secondary/regenerating IF. We tested the hypothesis that DB had value for conserving forest-dependent avian taxonomic and functional diversity, as (a) DB is situated with in the forest-anthropogenic land-use mosaic and (b) birds maintain diverse ecosystem functions and are sensitive to environmental change given their varied biological traits. We conducted 149 and 112 fixed-radius point-count surveys of avian communities in 99, and 24, patches of DB and IF, respectively, at each location recording microhabitat vegetation structure. We compared vegetation characteristics and taxonomic species richness between vegetation classes, and tested the breadth of functional trait-space and for significant associations with vegetation structures at each survey location, using RLQ analysis. Vegetation classes differed significantly, but floral species overlap and vegetation structures in DB closely resembled regenerating IF habitat. Specialist ground-nesting and insect-gleaning species corresponded to taller, more diverse IF structures. Other biological traits and total species richness overlapped broadly across both classes, but IF had significantly higher mean species richness. Given the relatively high taxonomic and functional diversity of the avian community in the abundant DB, the scarcity of IF, and the proximity of DB to the anthropogenic land-use mosaic, we recommend allocating suitable DB patches to the Protected Area Network, which may simultaneously help preserve avian taxonomic and functional diversity , facilitate colonisation throughout the fragmented landscape and provide ecosystem services to anthropogenic land uses.
The Howard College Campus (HCC) of the University of KwaZulu-Natal, South Africa, is a registered... more The Howard College Campus (HCC) of the University of KwaZulu-Natal, South Africa, is a registered Conservancy and houses the Msinsi Nature Reserve. A resident population of feral cats (Felis catus) resides on campus. There are two opposing views about these animals; one is that, by killing birds, lizards and small mammals, they negatively affect native wildlife, another is that management efforts, such as feeding and sterilization, minimize predation on wildlife and control cat numbers. The outcome of this debate is crucial in developing long-term management goals for the campus Conservancy. This study represents an assessment of stakeholder perceptions regarding the feral cat population. Participants observed feral cats in areas with feeding stations. Feeding was the main activity observed. Feelings towards the cats were generally positive. There was strong opposition to the eradication of the entire population; respondents did not consider feral cats an invasive alien species, rather a benign exotic species. The management implications of these findings are significant and these views should be considered in developing a management strategy. Further research should explore the use of feeding stations and sterilization, but additional research is necessary to determine the impact of feral cats on wildlife in and around the Conservancy.
To prevent the extinction of one of South Africa's rarest and most charismatic birds, the Ca... more To prevent the extinction of one of South Africa's rarest and most charismatic birds, the Cape Parr ot, captive breeding is being undertaken. Aviculturalists, some of whom contribute to the demise of the species, through capture and illegal trade, are making a significant contribution to its survival, through a breeding programme. This is welcome and beneficial. The parr ots already decimated in the wild, have recently been subjected to another threat, in the form of parrot beak and feather disease, which has caused the mortality of most of the birds in captivity. This ...
In Africa, four genera represent the family Psittacidae; of these, the genus Poicephalus Swainson... more In Africa, four genera represent the family Psittacidae; of these, the genus Poicephalus Swainson is endemic and comprises nine species. Three subspecies of the Cape Parrot, Poicephalus robustus (Gmelin), are often recognized. The endangered nominate subspecies, P. r. robustus, inhabits afromontane forest habitats and is endemic to South Africa. Poicephalus r. suahelicus (Reichenow) occurs in low-lying woodland in south-central Africa. The little-known third subspecies, P. r. fuscicollis (Kuhl), historically occurred from ...
Wild parrots represent one of the greatest commercial interests in the legal trade in wild birds.... more Wild parrots represent one of the greatest commercial interests in the legal trade in wild birds. Although it is difficult to quantify, there is a considerable illegal trade in wild parrots. Thirty-six per cent of the world's parrot species are listed by the International Union for the Conservation of Nature as threatened or near threatened, and 55% of these are threatened to some degree by trade. In this paper, we investigate the impact of protection on the number of nests that failed because of nestlings being taken by humans (hereafter nest take) and on nesting success in parrots. We collate data on parrot nest take from published and unpublished studies from Africa, Asia and Australasia, including countries and sites with and without national and local parrot protection measures in place. Nest take was insignificant in Australia, where all studies were from areas with both local and national protection. For less developed countries, levels of nest take were variable between studies, spanning the whole range from 0 to 100%. Protection significantly reduced nest take and correspondingly increased nesting success. Our results corroborate those for the Neotropics; thus, the advantages of protection appear to be independent of geographical location or political and economic conditions. We analysed data on legal trade in wild-caught parrots before and after implementation of the 1992 Wild Bird Conservation Act (which practically eliminated import of parrots to the USA) and found that there was no apparent shift in parrot imports to other global regions from the Neotropics. We suggest that conservation of parrots globally would benefit from similar legislation introduced in other regions, such as the EU (15), which is responsible for more than 60% of global imports of wild parrots.
Abstract: Little is known about snags in South African indigenous forests. Because of their value... more Abstract: Little is known about snags in South African indigenous forests. Because of their value to wildlife, we initiated this study to quantify snag characteristics and dynamics. We also investigated forest structure (woody component and snags) and forest use by avian species of conservation concern. We examined tree species composition, abundance and tree size in eight Afromontane mixed Podocarpus forests in KwaZulu-Natal, South Africa. In addition, we investigated the succession of snags at the level of individual trees. Large ...
Over a 50 year period the Cape White-eye Zosterops pallidus was the 13th most common bird species... more Over a 50 year period the Cape White-eye Zosterops pallidus was the 13th most common bird species ringed in southern Africa (Oschadleus & Underhill 1999). If not for specifically targeted species like European Swallow Hirundo rustica, African Penguin Spheniscus demersus and Redbilled Quelea Quelea quelea, it would possibly rate higher up the list. The Cape White-eye is common in KwaZulu-Natal (KZN)(Maclean 1994; Nuttall 1997), yet little is documented on the timing of breeding, moult and movements in the region. This ...
Abstract: Features of its breeding and feeding biology make the Cape parrot demographically vulne... more Abstract: Features of its breeding and feeding biology make the Cape parrot demographically vulnerable. It occurs in the fragmented fromontane forest in the Eastern Cape and KwaZulu-Natal, South Africa. Population numbers have declined significantly in recent years. Possible factors contributing to this decline include habitat loss, food shortage, the low reproductive rate, human predation and disease. Selective felling of spp., the preferred food tree and nest site species, has caused food shortage and nest site scarcity. ...
Over a three-year period, between January 2014 and December 2016, I conducted research within the... more Over a three-year period, between January 2014 and December 2016, I conducted research within the Indian Ocean Coastal Belt (Coastal Belt) of the Ugu district of south-east KwaZulu-Natal Province, an area that falls within the Pondoland Area of Endemism. The study region consists of a mixed land-use mosaic, where naturally-and anthropogenically-fragmented indigenous forest and coastal thicket/dense bush (hereafter dense bush) patches are nested within an anthropogenic landscape. The major land-use types within the region are agriculture (predominantly sugarcane) and "urban" landscapes (more accurately described as exurban sprawl or rural villages) which are extensively tourism-oriented developments. The mammalian communities of the area have received little research attention in the past, and although ecological parameters have been established for certain species from other regions, the effects of anthropogenic impacts on the persistence of forest mammals within the habitat patches of the Coastal Belt have thus far been unexplored. The persistence of metapopulations within fragmented landscapes depends on matrix composition and permeability; thus, assessing landscape-scale factors within the habitat mosaic and the impact of the anthropogenic disturbance across a sufficiently representative spatial and temporal scale is crucial for conservation planning.
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Papers by Colleen Downs