Shane McPherson | University of KwaZulu-Natal (original) (raw)
Papers by Shane McPherson
Ostrich
The ranging behaviour of raptors in human-altered environments, such as agricultural and suburban... more The ranging behaviour of raptors in human-altered environments, such as agricultural and suburban landscapes, is becoming increasingly important for conservationists in the context of unprecedented high rates of anthropogenic land use change. We studied the movement ecology of adult Long-crested Eagles Lophaetus occipitalis fitted with geographic positioning system transmitters in an agricultural landscape in KwaZulu-Natal Province, South Africa. Mean home ranges (± SD) of males and females estimated using the autocorrelated kernel density estimator (AKDE) method were 608 ± 552 ha (n = 5) and 664 ± 844 ha (n = 4), respectively. Core areas (KDE href 50%) were estimated as 80 ± 38 ha and 39 ± 20 ha for males and females, respectively. We also recorded exploratory behaviour (in the form of long excursions) in two of the birds, of up to 49 km from the centre of their home range. The relatively small home ranges reported in this study are suggestive of productive foraging habitats whereby Long-crested Eagles can meet their energy requirements without having to travel long distances to obtain resources. Consistent with predictions, non-breeding male and female Long-crested Eagles showed similar ranging behaviour, which includes occasional exploratory behaviour. Comportement des Aigles huppards Lophaetus occipitalis dans les paysages modifiés par l'homme du KwaZulu-Natal, Afrique du Sud Le comportement des rapaces dans les environnements modifiés par l'homme, tels que les paysages agricoles et suburbains, devient de plus en plus important pour les défenseurs de la nature dans le contexte des taux élevés sans précédent de changement d'utilisation des terres par l'homme. Nous avons étudié l'écologie du mouvement des Aigles huppards adultes Lophaetus occipitalis équipés d'émetteurs de système de positionnement géographique dans un paysage agricole de la province du KwaZulu-Natal, en Afrique du Sud. Les domaines vitaux moyens (± SD) des mâles et des femelles estimés à l'aide de la méthode de l'estimateur de densité de noyau autocorrélé (AKDE) étaient respectivement de 608 ± 552 ha (n = 5) et 664 ± 844 ha (n = 4). Les zones centrales (KDE href 50%) ont été estimées à 80 ± 38 ha et 39 ± 20 ha respectivement pour les mâles et les femelles. Nous avons également enregistré un comportement exploratoire (sous forme de longues excursions) chez deux des oiseaux, jusqu'à 49 km du centre de leur domaine vital. Les domaines vitaux relativement petits signalés dans cette étude suggèrent des habitats de gagnage productifs où l'Aigle huppard peut satisfaire ses besoins énergétiques sans avoir à parcourir de longues distances pour obtenir des ressources. Conformément aux prévisions, les Aigles huppards mâles et femelles non reproducteurs ont montré un comportement territorial similaire, y compris un comportement exploratoire occasionnel.
Urban environments comprise a complex and dynamic landscape, and urban sprawl is irreversibly tra... more Urban environments comprise a complex and dynamic landscape, and urban sprawl is irreversibly transforming large areas of land globally. Increasingly, the need for incorporating ecosystem services into urban landscapes provides opportunities for greenspace to benefit biodiversity and indigenous wildlife. Enhancing urban green-space maximises indigenous biodiversity and provides conservation value, and can also benefit people by enriching their experience and awareness of nature. Large charismatic species can stimulate awe and interest as emblematic representatives of the wilderness. As the global population becomes ever more urban, this enriches the human experience. The crowned eagle (Stephanoaetus coronatus) is a large predatory raptor and a threatened species that is increasingly known to inhabit the Durban Metropolitan Open Space System (D'MOSS), within eThekwini municipality, KwaZulu-Natal (KZN), South Africa. This research investigated the ecology of the crowned eagle in the urban environment and suggests opportunities for enhancing the urban landscape for conservation benefits. Globally, dramatic land use change typical of urbanisation negatively affects biodiversity, especially for top predators. The D'MOSS design 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. Understanding habitat use of keystone and apex species provides urban planners with an opportunity to integrate biodiversity in a growing city. Consequently, we investigated habitat use and nest site selection of crowned eagles 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. Further, home range and habitat selection were investigated with GPS telemetry, albeit with a limited sample size (n =5) due to the limitations of abundance and dispersion of this apex predator. The 350 km 2 urban core study area comprised a matrix of mainly formal settlements (44%), and DMOSS green space areas (29%). The study area was occupied by up to 22 active breeding pairs of crowned eagles. We documented a mean (n = 4) annual home range of 13 km 2 (hull 100%) containing 6.3 km 2 of territory per pair (LKDE H LSCV 95%). These relatively small home ranges for a large eagle included shared territorial boundaries. Rapid replacement of vacancies at breeding sites suggests a saturated population. Habitat selection within the home range, thresholds of critical habitat, exotic trees, and correlation with DMOSS show the importance of pockets of indigenous forest in this urban mosaic landscape. These forests are fragmented and fragmentation increases the available edge habitats and landscape heterogeneity, potentially enhancing resource availability for crowned eagles in a highly modified landscape. The presence of remnant patches of mature Eucalyptus was more preferred than monotypic timber plantation stands. Consequently, continued protection of the D'MOSS system, and a considered approach to management of Eucalyptus are required for the persistence of the crowned eagle in this landscape The study of diet is pivotal in understanding a species, particularly for quantifying a predatory raptors' economic niche and potential for human-wildlife conflict. In close association with urban development, the local population of crowned eagles has the potential to be a concern to the safety of domestic stock and pets. Time-lapse cameras were positioned at urban nest sites (n = 11) to identify the prey composition during breeding, particularly in regards to taxa with human associations. This was the first use of this technique for this species. The numerical proportion of avian prey, particularly hadeda ibis (Bostrychia hagedash) pulli, was several times greater than any previous diet description. The methodology used and the abundance of hadeda ibis in these urban environments are potential contributing factors. Rock hyrax (Procavia capensis) was the primary prey and where hyrax were unavailable, the diet composition was broader and included more vervet monkeys (Chlorocebus pygerythrus). Domestic stock comprised only 6% of the identifiable prey. Contrary to popular belief, no dogs (Canis familiaris) and few cats (Felis catus) were delivered to the nest by breeding eagles in this study. In situ pet attacks are most frequently attributed to juvenile and immature crowned eagles in winter and spring. Attacks on pets by crowned eagles, especially on small dog breeds, although relatively rare have a substantial influence on human-wildlife conflict and public perceptions. Pet attacks are generally attributed to juvenile and immature crowned eagles during periods of limited resources, particularly winter and during dispersal in the juveniles' first spring. Negative social perceptions have resulted in persecution (n = 5), one of the main causes of recorded injury and mortality to crowned eagles in the region. Gunshot persecution, electrocution and collisions with anthropogenic structures have the greatest impact on juvenile and immature survival in the region. We provide management recommendations regarding various categories of crowned eagle human-wildlife interactions. Collaboration of wildlife authorities with NGO's and public stakeholder input creates an environment for successful crowned eagle conservation and management of human-wildlife conflicts. Public awareness is an important aspect to the sustainability of the urban crowned eagle population. This study demonstrates that urban mosaic landscapes can provide conservation benefits for the crowned eagle. The land planning strategies enacted in Durban can guide urban expansion in tropical forest biomes to enhance indigenous biodiversity in urban mosaic landscapes in Africa, and globally.
Contrasting parental color-morphs increase regularity of prey deliveries in an African raptor: Data
The paper based on this dataset has been published in Behavioral Ecology with the title "Con... more The paper based on this dataset has been published in Behavioral Ecology with the title "Contrasting parental color-morphs increase regularity of prey deliveries in an African raptor"<br>Abstract: Disassortative mating in color-polymorphic raptors is a proposed mechanism for the maintenance of color polymorphism in populations. Selection for such a mating system may occur if there are fitness advantages of mating with a contrasting morph. In the black sparrowhawk (Accipiter melanoleucus), mixed-morph pairs may have a selective advantage, since they produce offspring which have higher survival rates. Two hypotheses, which may explain the mechanism, are the 'avoidance-image' and 'complementarity' hypotheses: The first suggests that within a predator's territory, prey develop a search-image for the more commonly encountered parental morph, for example, the male morph during incubation and brooding. Females of a contrasting morph to their partner woul...
Diet of the crowned eagle (Stephanoaetus coronatus) in an urban landscape: potential for human-wildlife conflict?
Urban Ecosystems, 2015
The study of diet is pivotal in understanding a species, particularly for quantifying a predatory... more The study of diet is pivotal in understanding a species, particularly for quantifying a predatory raptors’ economic niche and potential for human-wildlife conflict. The crowned eagle (Stephanoaetus coronatus) is one of Africa’s apex predators and a population is present within the urban greenspace mosaic of Durban and Pietermaritzburg, KwaZulu-Natal, South Africa. In close association with urban development, the local population of crowned eagles has the potential to be a concern to the safety of domestic stock and pets. Time-lapse cameras were positioned at urban nest sites (n = 11) to identify the prey composition during breeding, particularly in regards to taxa with human associations. The numerical proportion of avian prey, particularly hadeda ibis (Bostricia hagedash) pulli, was several times greater than any previous diet description. The methodology used and the abundance of hadeda ibis in these urban environments are potential contributing factors. Rock hyrax (Procavia capensis) was the primary prey and where hyrax were unavailable, the diet composition was broader and included more vervet monkeys (Chlorocebus pygerythrus). It was found that domestic stock comprised 6 % of the identifiable prey. Contrary to popular belief, no dogs (Canis familiaris) and few cats (Felis domesticus) were delivered to the nest by breeding eagles in this study. The negative consequences of small proportions of pet losses should be considered against the majority of wildlife prey consumed, which also have various wildlife conflict interactions. Juvenile and sub-adult eagles are most frequently identified at in situ attacks of pets, particularly toy dog breeds. Further research on juvenile dispersal and winter diet will provide insights on the ecological impacts of eagle management strategies in the region.
Surviving the Urban Jungle: Anthropogenic Threats, Wildlife-Conflicts, and Management Recommendations for African Crowned Eagles
Larger carnivores often trigger human-wildlife conflicts that arise from perceived threats to hum... more Larger carnivores often trigger human-wildlife conflicts that arise from perceived threats to humans and domestic animals’ safety, which generate the need for management and removal strategies. These issues become especially challenging when humans and wildlife coexist close to one another, for example, in urban landscapes. African Crowned Eagles (Stephanoaetus coronatus) are powerful forest raptors that breed within the metropolitan green-space system of Durban and Pietermaritzburg, South Africa. Negative human-wildlife interactions can occur because eagles occasionally predate on pets, such as cats (Felis catus) and small dogs (Canis lupus familiaris), and provisioning domestic stock to nest sites has previously been quantified. Here, wildlife management becomes critical, usually aimed at reducing or eliminating causes of economic or social harm, but have to be balanced against conservation goals regarding threatened species. In this study, we (i) identified causes of harm or loss...
Urbanization is associated with increased breeding rate, but decreased breeding success, in an urban population of near-threatened African Crowned Eagles
Urban areas can be attractive to certain species because of increased food abundance and nesting ... more Urban areas can be attractive to certain species because of increased food abundance and nesting availability, which in turn may increase productivity or breeding rates. However, there are also potential costs associated with urban living such as higher nest failure, poorer body condition, or increased prevalence of disease. These costs may result in species trading off the number of young produced against the condition of their young. African Crowned Eagles (Stephanoaetus coronatus) are a rare example of large, powerful apex predators that breed in some urban areas in Africa. In this study, we explored the breeding performance of these eagles across an urbanization gradient in KwaZulu-Natal Province, South Africa, over 7 breeding seasons. We predicted that living in an urban environment would increase productivity through an increase in breeding rate (shifting from typically biennial breeding to annual breeding). We then explored if there were any hidden costs associated with such ...
Home Range of a Large Forest Eagle in a Suburban Landscape: Crowned Eagles (Stephanoaetus coronatus) in the Durban Metropolitan Open Space System, South Africa
Journal of Raptor Research
Abstract. Apex predators are sensitive to human disturbance and persecution, often becoming the f... more Abstract. Apex predators are sensitive to human disturbance and persecution, often becoming the first losses in a declining urban wildlife community. A population of Crowned Eagles (Stephanoaetus coronatus) within eThekwini municipality, KwaZulu-Natal, South Africa, persists in a green space network called the Durban Metropolitan Open Space System (DMOSS). We used GPS–UHF telemetry to investigate the home range and habitat use of five breeding adult Crowned Eagles for 1 yr. We documented a mean annual home range for four birds of 13 km2 (Minimum Convex Polygon [MCP] 100%), or 6.3 km2 (Kernel Density Estimator [KDE], bandwith HLSCV 95%), equating to small home ranges for this large eagle, compared with other large eagles. Habitat use within home ranges and correlation with DMOSS area underscored the importance of retaining forest patches in the urban mosaic landscape to encourage the persistence of this large raptor. Our study highlighted the importance of planning green space in future city expansion and land development. The spatial and habitat associations of Crowned Eagles may be used to inform urban planners who wish to support biodiverse communities that include apex predators in an urban landscape.
Modification of the third phase in the framework for vertebrate species persistence in urban mosaic environments
Ambio
Ostrich
Globally, but especially in Africa, increasing human populations and anthropogenic land-use chang... more Globally, but especially in Africa, increasing human populations and anthropogenic land-use change are generally affecting diversity negatively. Urban environments in southern Africa typically comprise a mosaic landscape of anthropogenic infrastructure with some green spaces. These urban cities have a range of fauna that have persisted or increased in population density compared with areas that are more natural. We analysed the occurrence of diurnal and nocturnal raptors using South African Bird Atlas Project (SABAP2) data and reviewed literature. We found 66 raptor species occurred in South African cities. Thirty species had reporting frequencies greater than 10% in at least one of the 11 cities assessed, revealing impressive diversity of the raptor clade in South African cities. Five species were both abundant and widespread, occurring >10% in five or more cities each, of which three belong to the scavenger guild: Black-winged Kite Elanus caeruleus, African Fish Eagle Haliaeetus vocifer, Common Buzzard Buteo buteo vulpinus, Yellow-billed Kite Milvus aegyptius and Black Sparrowhawk Accipiter melanoleucus. However, only a few of these 66 raptors had been extensively studied in urban areas: the Black Sparrowhawk, African Crowned Eagle Stephanoaetus coronatus, Lanner Falcon Falco biarmicus and Peregrine Falcon Falco peregrinus. This lack of research is specifically severe, given that Africa is hosting a unique and diverse range of raptor species and that numbers and diversity of raptors have declined dramatically over the past decades across the continent. In fact, these four extensively studied species occurred in higher densities in urban areas than rural areas, which indicates that urban areas might create valuable opportunities for urban conservation, not least through public engagement. Rapaces sud-africains dans les paysages urbains: un bilan À l›échelle mondiale, mais surtout en Afrique, l›augmentation des populations humaines et les changements anthropiques d›utilisation des terres ont généralement un impact négatif sur la diversité. Les environnements urbains en Afrique australe comprennent généralement un paysage en mosaïque d›infrastructures anthropiques avec quelques espaces verts. Ces villes urbaines ont une diversité de faune qui a persisté ou a augmenté en densité de population par rapport aux zones plus naturelles. Nous avons analysé l›occurrence des rapaces diurnes et nocturnes à l›aide des données du South African Bird Atlas Project (SABAP2) et examiné la littérature. Nous avons trouvé 66 espèces de rapaces présentes dans les villes sud-africaines. Trente espèces avaient des fréquences de déclaration supérieures à 10% dans au moins l'une des 11 villes évaluées, révélant une diversité impressionnante du clade des rapaces dans les villes sud-africaines. Cinq espèces étaient à la fois abondantes et répandues, présentes> 10% dans cinq villes ou plus chacune, dont trois appartiennent à la guilde des charognards: l'Elanion blanc Elanus caeruleus, le Pygargue vocifer Haliaeetus vocifer, la Buse commune Buteo buteo vulpinus, Le Milan à bec jaune Milvus aegyptius et l'Epervier noir Accipiter melanoleucus. Cependant, seuls quelques-uns de ces 66 rapaces avaient été largement étudiés dans les zones urbaines: l'Epervier noir, l'Aigle couronné Stephanoaetus coronatus, le Faucon lanier Falco biarmicus et le Faucon pèlerin Falco peregrinus. Ce manque de recherche est particulièrement grave, étant donné que l'Afrique abrite une gamme unique et diversifiée d'espèces de rapaces et que le nombre et la diversité des rapaces ont considérablement diminué au cours des dernières décennies à travers le continent. En fait, ces quatre espèces largement étudiées se trouvaient à des densités plus élevées dans les zones urbaines que dans les zones rurales, ce qui indique que les zones urbaines pourraient créer de précieuses opportunités pour la conservation urbaine, notamment grâce à l'engagement du public.
Diet of nestling African woolly‐necked storks in suburban areas of KwaZulu‐Natal, South Africa
African Journal of Ecology
Temporal changes in prey composition and biomass delivery to African Crowned Eagle nestlings in urban areas of KwaZulu-Natal, South Africa
Ostrich
Contrasting parental color morphs increase regularity of prey deliveries in an African raptor
Behavioral Ecology
Disassortative mating in color-polymorphic raptors is a proposed mechanism for the maintenance of... more Disassortative mating in color-polymorphic raptors is a proposed mechanism for the maintenance of color polymorphism in populations. Selection for such a mating system may occur if there are fitness advantages of mating with a contrasting morph. In the black sparrowhawk (Accipiter melanoleucus), mixed-morph pairs may have a selective advantage because they produce offspring that have higher survival rates. Two hypotheses, which may explain the mechanism, are the “avoidance-image” and “complementarity” hypotheses. The first suggests that, within a predator’s territory, prey develop a search image for the more commonly encountered parental morph, for example, the male morph during incubation and brooding. Females of a contrasting morph to their partner would then have higher capture rates once they commence hunting in the later nestling phase. Thus, the “avoidance-image” hypothesis predicts higher provisioning rates for mixed-morph pairs. Alternatively, the “complementarity” hypothesi...
Gender-related morphometric differences in mature and nestling Crowned Eagles, with comments on ringing of eagle nestlings in KwaZulu-Natal, South Africa
Ostrich
Crowned eagle nest sites in an urban landscape: Requirements of a large eagle in the Durban Metropolitan Open Space System
Landscape and Urban Planning, 2016
• 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.
Crowned eagle nest sites in an urban landscape: Requirements of a large eagle in the Durban Metropolitan Open Space System
Landscape and Urban Planning, 2016
• 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.
The study of diet is pivotal in understanding a species, particularly for quantifying a predator... more The study of diet is pivotal in understanding a species, particularly for quantifying a predatory raptors’ economic niche and potential for human-wildlife conflict. The crowned eagle (Stephanoaetus coronatus) is one of Africa’s apex predators and a population is present within the urban greenspace mosaic of Durban and Pietermaritzburg, KwaZulu-Natal, South Africa. In close association with urban development, the local population of crowned eagles has the potential to be a concern to the safety of domestic stock and pets. Time-lapse cameras were positioned at urban nest sites (n=11) to identify the prey composition during breeding, particularly in regards to taxa with human associations. The numerical proportion of avian prey, particularly hadeda ibis (Bostricia hagedash) pulli, was several times greater than any previous diet description. The methodology used and the abundance of hadeda ibis in these urbanenvironmentsarepotential contributing factors. Rock hyrax (Procavia capensis)was the primary prey and where hyrax were unavailable, the diet composition was broader and included more vervet monkeys (Chlorocebus pygerythrus). It was found that domestic stock comprised 6 % of the identifiable prey. Contrary to popular belief, no dogs (Canis familiaris) andfew cats(Felisdomesticus) weredelivered tothe nest bybreedingeagles in this study. The negative consequences of small proportions of pet losses should be considered against the majority of wildlife prey consumed, which also have various wildlife conflict interactions. Juvenile and sub-adult eagles are most frequently identified at in situ attacks of pets, particularly toy dog breeds. Further research on juvenile dispersal and winter diet will provide insights on the ecological impacts of eagle management strategies in the region.
Ostrich
The ranging behaviour of raptors in human-altered environments, such as agricultural and suburban... more The ranging behaviour of raptors in human-altered environments, such as agricultural and suburban landscapes, is becoming increasingly important for conservationists in the context of unprecedented high rates of anthropogenic land use change. We studied the movement ecology of adult Long-crested Eagles Lophaetus occipitalis fitted with geographic positioning system transmitters in an agricultural landscape in KwaZulu-Natal Province, South Africa. Mean home ranges (± SD) of males and females estimated using the autocorrelated kernel density estimator (AKDE) method were 608 ± 552 ha (n = 5) and 664 ± 844 ha (n = 4), respectively. Core areas (KDE href 50%) were estimated as 80 ± 38 ha and 39 ± 20 ha for males and females, respectively. We also recorded exploratory behaviour (in the form of long excursions) in two of the birds, of up to 49 km from the centre of their home range. The relatively small home ranges reported in this study are suggestive of productive foraging habitats whereby Long-crested Eagles can meet their energy requirements without having to travel long distances to obtain resources. Consistent with predictions, non-breeding male and female Long-crested Eagles showed similar ranging behaviour, which includes occasional exploratory behaviour. Comportement des Aigles huppards Lophaetus occipitalis dans les paysages modifiés par l'homme du KwaZulu-Natal, Afrique du Sud Le comportement des rapaces dans les environnements modifiés par l'homme, tels que les paysages agricoles et suburbains, devient de plus en plus important pour les défenseurs de la nature dans le contexte des taux élevés sans précédent de changement d'utilisation des terres par l'homme. Nous avons étudié l'écologie du mouvement des Aigles huppards adultes Lophaetus occipitalis équipés d'émetteurs de système de positionnement géographique dans un paysage agricole de la province du KwaZulu-Natal, en Afrique du Sud. Les domaines vitaux moyens (± SD) des mâles et des femelles estimés à l'aide de la méthode de l'estimateur de densité de noyau autocorrélé (AKDE) étaient respectivement de 608 ± 552 ha (n = 5) et 664 ± 844 ha (n = 4). Les zones centrales (KDE href 50%) ont été estimées à 80 ± 38 ha et 39 ± 20 ha respectivement pour les mâles et les femelles. Nous avons également enregistré un comportement exploratoire (sous forme de longues excursions) chez deux des oiseaux, jusqu'à 49 km du centre de leur domaine vital. Les domaines vitaux relativement petits signalés dans cette étude suggèrent des habitats de gagnage productifs où l'Aigle huppard peut satisfaire ses besoins énergétiques sans avoir à parcourir de longues distances pour obtenir des ressources. Conformément aux prévisions, les Aigles huppards mâles et femelles non reproducteurs ont montré un comportement territorial similaire, y compris un comportement exploratoire occasionnel.
Urban environments comprise a complex and dynamic landscape, and urban sprawl is irreversibly tra... more Urban environments comprise a complex and dynamic landscape, and urban sprawl is irreversibly transforming large areas of land globally. Increasingly, the need for incorporating ecosystem services into urban landscapes provides opportunities for greenspace to benefit biodiversity and indigenous wildlife. Enhancing urban green-space maximises indigenous biodiversity and provides conservation value, and can also benefit people by enriching their experience and awareness of nature. Large charismatic species can stimulate awe and interest as emblematic representatives of the wilderness. As the global population becomes ever more urban, this enriches the human experience. The crowned eagle (Stephanoaetus coronatus) is a large predatory raptor and a threatened species that is increasingly known to inhabit the Durban Metropolitan Open Space System (D'MOSS), within eThekwini municipality, KwaZulu-Natal (KZN), South Africa. This research investigated the ecology of the crowned eagle in the urban environment and suggests opportunities for enhancing the urban landscape for conservation benefits. Globally, dramatic land use change typical of urbanisation negatively affects biodiversity, especially for top predators. The D'MOSS design 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. Understanding habitat use of keystone and apex species provides urban planners with an opportunity to integrate biodiversity in a growing city. Consequently, we investigated habitat use and nest site selection of crowned eagles 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. Further, home range and habitat selection were investigated with GPS telemetry, albeit with a limited sample size (n =5) due to the limitations of abundance and dispersion of this apex predator. The 350 km 2 urban core study area comprised a matrix of mainly formal settlements (44%), and DMOSS green space areas (29%). The study area was occupied by up to 22 active breeding pairs of crowned eagles. We documented a mean (n = 4) annual home range of 13 km 2 (hull 100%) containing 6.3 km 2 of territory per pair (LKDE H LSCV 95%). These relatively small home ranges for a large eagle included shared territorial boundaries. Rapid replacement of vacancies at breeding sites suggests a saturated population. Habitat selection within the home range, thresholds of critical habitat, exotic trees, and correlation with DMOSS show the importance of pockets of indigenous forest in this urban mosaic landscape. These forests are fragmented and fragmentation increases the available edge habitats and landscape heterogeneity, potentially enhancing resource availability for crowned eagles in a highly modified landscape. The presence of remnant patches of mature Eucalyptus was more preferred than monotypic timber plantation stands. Consequently, continued protection of the D'MOSS system, and a considered approach to management of Eucalyptus are required for the persistence of the crowned eagle in this landscape The study of diet is pivotal in understanding a species, particularly for quantifying a predatory raptors' economic niche and potential for human-wildlife conflict. In close association with urban development, the local population of crowned eagles has the potential to be a concern to the safety of domestic stock and pets. Time-lapse cameras were positioned at urban nest sites (n = 11) to identify the prey composition during breeding, particularly in regards to taxa with human associations. This was the first use of this technique for this species. The numerical proportion of avian prey, particularly hadeda ibis (Bostrychia hagedash) pulli, was several times greater than any previous diet description. The methodology used and the abundance of hadeda ibis in these urban environments are potential contributing factors. Rock hyrax (Procavia capensis) was the primary prey and where hyrax were unavailable, the diet composition was broader and included more vervet monkeys (Chlorocebus pygerythrus). Domestic stock comprised only 6% of the identifiable prey. Contrary to popular belief, no dogs (Canis familiaris) and few cats (Felis catus) were delivered to the nest by breeding eagles in this study. In situ pet attacks are most frequently attributed to juvenile and immature crowned eagles in winter and spring. Attacks on pets by crowned eagles, especially on small dog breeds, although relatively rare have a substantial influence on human-wildlife conflict and public perceptions. Pet attacks are generally attributed to juvenile and immature crowned eagles during periods of limited resources, particularly winter and during dispersal in the juveniles' first spring. Negative social perceptions have resulted in persecution (n = 5), one of the main causes of recorded injury and mortality to crowned eagles in the region. Gunshot persecution, electrocution and collisions with anthropogenic structures have the greatest impact on juvenile and immature survival in the region. We provide management recommendations regarding various categories of crowned eagle human-wildlife interactions. Collaboration of wildlife authorities with NGO's and public stakeholder input creates an environment for successful crowned eagle conservation and management of human-wildlife conflicts. Public awareness is an important aspect to the sustainability of the urban crowned eagle population. This study demonstrates that urban mosaic landscapes can provide conservation benefits for the crowned eagle. The land planning strategies enacted in Durban can guide urban expansion in tropical forest biomes to enhance indigenous biodiversity in urban mosaic landscapes in Africa, and globally.
Contrasting parental color-morphs increase regularity of prey deliveries in an African raptor: Data
The paper based on this dataset has been published in Behavioral Ecology with the title "Con... more The paper based on this dataset has been published in Behavioral Ecology with the title "Contrasting parental color-morphs increase regularity of prey deliveries in an African raptor"<br>Abstract: Disassortative mating in color-polymorphic raptors is a proposed mechanism for the maintenance of color polymorphism in populations. Selection for such a mating system may occur if there are fitness advantages of mating with a contrasting morph. In the black sparrowhawk (Accipiter melanoleucus), mixed-morph pairs may have a selective advantage, since they produce offspring which have higher survival rates. Two hypotheses, which may explain the mechanism, are the 'avoidance-image' and 'complementarity' hypotheses: The first suggests that within a predator's territory, prey develop a search-image for the more commonly encountered parental morph, for example, the male morph during incubation and brooding. Females of a contrasting morph to their partner woul...
Diet of the crowned eagle (Stephanoaetus coronatus) in an urban landscape: potential for human-wildlife conflict?
Urban Ecosystems, 2015
The study of diet is pivotal in understanding a species, particularly for quantifying a predatory... more The study of diet is pivotal in understanding a species, particularly for quantifying a predatory raptors’ economic niche and potential for human-wildlife conflict. The crowned eagle (Stephanoaetus coronatus) is one of Africa’s apex predators and a population is present within the urban greenspace mosaic of Durban and Pietermaritzburg, KwaZulu-Natal, South Africa. In close association with urban development, the local population of crowned eagles has the potential to be a concern to the safety of domestic stock and pets. Time-lapse cameras were positioned at urban nest sites (n = 11) to identify the prey composition during breeding, particularly in regards to taxa with human associations. The numerical proportion of avian prey, particularly hadeda ibis (Bostricia hagedash) pulli, was several times greater than any previous diet description. The methodology used and the abundance of hadeda ibis in these urban environments are potential contributing factors. Rock hyrax (Procavia capensis) was the primary prey and where hyrax were unavailable, the diet composition was broader and included more vervet monkeys (Chlorocebus pygerythrus). It was found that domestic stock comprised 6 % of the identifiable prey. Contrary to popular belief, no dogs (Canis familiaris) and few cats (Felis domesticus) were delivered to the nest by breeding eagles in this study. The negative consequences of small proportions of pet losses should be considered against the majority of wildlife prey consumed, which also have various wildlife conflict interactions. Juvenile and sub-adult eagles are most frequently identified at in situ attacks of pets, particularly toy dog breeds. Further research on juvenile dispersal and winter diet will provide insights on the ecological impacts of eagle management strategies in the region.
Surviving the Urban Jungle: Anthropogenic Threats, Wildlife-Conflicts, and Management Recommendations for African Crowned Eagles
Larger carnivores often trigger human-wildlife conflicts that arise from perceived threats to hum... more Larger carnivores often trigger human-wildlife conflicts that arise from perceived threats to humans and domestic animals’ safety, which generate the need for management and removal strategies. These issues become especially challenging when humans and wildlife coexist close to one another, for example, in urban landscapes. African Crowned Eagles (Stephanoaetus coronatus) are powerful forest raptors that breed within the metropolitan green-space system of Durban and Pietermaritzburg, South Africa. Negative human-wildlife interactions can occur because eagles occasionally predate on pets, such as cats (Felis catus) and small dogs (Canis lupus familiaris), and provisioning domestic stock to nest sites has previously been quantified. Here, wildlife management becomes critical, usually aimed at reducing or eliminating causes of economic or social harm, but have to be balanced against conservation goals regarding threatened species. In this study, we (i) identified causes of harm or loss...
Urbanization is associated with increased breeding rate, but decreased breeding success, in an urban population of near-threatened African Crowned Eagles
Urban areas can be attractive to certain species because of increased food abundance and nesting ... more Urban areas can be attractive to certain species because of increased food abundance and nesting availability, which in turn may increase productivity or breeding rates. However, there are also potential costs associated with urban living such as higher nest failure, poorer body condition, or increased prevalence of disease. These costs may result in species trading off the number of young produced against the condition of their young. African Crowned Eagles (Stephanoaetus coronatus) are a rare example of large, powerful apex predators that breed in some urban areas in Africa. In this study, we explored the breeding performance of these eagles across an urbanization gradient in KwaZulu-Natal Province, South Africa, over 7 breeding seasons. We predicted that living in an urban environment would increase productivity through an increase in breeding rate (shifting from typically biennial breeding to annual breeding). We then explored if there were any hidden costs associated with such ...
Home Range of a Large Forest Eagle in a Suburban Landscape: Crowned Eagles (Stephanoaetus coronatus) in the Durban Metropolitan Open Space System, South Africa
Journal of Raptor Research
Abstract. Apex predators are sensitive to human disturbance and persecution, often becoming the f... more Abstract. Apex predators are sensitive to human disturbance and persecution, often becoming the first losses in a declining urban wildlife community. A population of Crowned Eagles (Stephanoaetus coronatus) within eThekwini municipality, KwaZulu-Natal, South Africa, persists in a green space network called the Durban Metropolitan Open Space System (DMOSS). We used GPS–UHF telemetry to investigate the home range and habitat use of five breeding adult Crowned Eagles for 1 yr. We documented a mean annual home range for four birds of 13 km2 (Minimum Convex Polygon [MCP] 100%), or 6.3 km2 (Kernel Density Estimator [KDE], bandwith HLSCV 95%), equating to small home ranges for this large eagle, compared with other large eagles. Habitat use within home ranges and correlation with DMOSS area underscored the importance of retaining forest patches in the urban mosaic landscape to encourage the persistence of this large raptor. Our study highlighted the importance of planning green space in future city expansion and land development. The spatial and habitat associations of Crowned Eagles may be used to inform urban planners who wish to support biodiverse communities that include apex predators in an urban landscape.
Modification of the third phase in the framework for vertebrate species persistence in urban mosaic environments
Ambio
Ostrich
Globally, but especially in Africa, increasing human populations and anthropogenic land-use chang... more Globally, but especially in Africa, increasing human populations and anthropogenic land-use change are generally affecting diversity negatively. Urban environments in southern Africa typically comprise a mosaic landscape of anthropogenic infrastructure with some green spaces. These urban cities have a range of fauna that have persisted or increased in population density compared with areas that are more natural. We analysed the occurrence of diurnal and nocturnal raptors using South African Bird Atlas Project (SABAP2) data and reviewed literature. We found 66 raptor species occurred in South African cities. Thirty species had reporting frequencies greater than 10% in at least one of the 11 cities assessed, revealing impressive diversity of the raptor clade in South African cities. Five species were both abundant and widespread, occurring >10% in five or more cities each, of which three belong to the scavenger guild: Black-winged Kite Elanus caeruleus, African Fish Eagle Haliaeetus vocifer, Common Buzzard Buteo buteo vulpinus, Yellow-billed Kite Milvus aegyptius and Black Sparrowhawk Accipiter melanoleucus. However, only a few of these 66 raptors had been extensively studied in urban areas: the Black Sparrowhawk, African Crowned Eagle Stephanoaetus coronatus, Lanner Falcon Falco biarmicus and Peregrine Falcon Falco peregrinus. This lack of research is specifically severe, given that Africa is hosting a unique and diverse range of raptor species and that numbers and diversity of raptors have declined dramatically over the past decades across the continent. In fact, these four extensively studied species occurred in higher densities in urban areas than rural areas, which indicates that urban areas might create valuable opportunities for urban conservation, not least through public engagement. Rapaces sud-africains dans les paysages urbains: un bilan À l›échelle mondiale, mais surtout en Afrique, l›augmentation des populations humaines et les changements anthropiques d›utilisation des terres ont généralement un impact négatif sur la diversité. Les environnements urbains en Afrique australe comprennent généralement un paysage en mosaïque d›infrastructures anthropiques avec quelques espaces verts. Ces villes urbaines ont une diversité de faune qui a persisté ou a augmenté en densité de population par rapport aux zones plus naturelles. Nous avons analysé l›occurrence des rapaces diurnes et nocturnes à l›aide des données du South African Bird Atlas Project (SABAP2) et examiné la littérature. Nous avons trouvé 66 espèces de rapaces présentes dans les villes sud-africaines. Trente espèces avaient des fréquences de déclaration supérieures à 10% dans au moins l'une des 11 villes évaluées, révélant une diversité impressionnante du clade des rapaces dans les villes sud-africaines. Cinq espèces étaient à la fois abondantes et répandues, présentes> 10% dans cinq villes ou plus chacune, dont trois appartiennent à la guilde des charognards: l'Elanion blanc Elanus caeruleus, le Pygargue vocifer Haliaeetus vocifer, la Buse commune Buteo buteo vulpinus, Le Milan à bec jaune Milvus aegyptius et l'Epervier noir Accipiter melanoleucus. Cependant, seuls quelques-uns de ces 66 rapaces avaient été largement étudiés dans les zones urbaines: l'Epervier noir, l'Aigle couronné Stephanoaetus coronatus, le Faucon lanier Falco biarmicus et le Faucon pèlerin Falco peregrinus. Ce manque de recherche est particulièrement grave, étant donné que l'Afrique abrite une gamme unique et diversifiée d'espèces de rapaces et que le nombre et la diversité des rapaces ont considérablement diminué au cours des dernières décennies à travers le continent. En fait, ces quatre espèces largement étudiées se trouvaient à des densités plus élevées dans les zones urbaines que dans les zones rurales, ce qui indique que les zones urbaines pourraient créer de précieuses opportunités pour la conservation urbaine, notamment grâce à l'engagement du public.
Diet of nestling African woolly‐necked storks in suburban areas of KwaZulu‐Natal, South Africa
African Journal of Ecology
Temporal changes in prey composition and biomass delivery to African Crowned Eagle nestlings in urban areas of KwaZulu-Natal, South Africa
Ostrich
Contrasting parental color morphs increase regularity of prey deliveries in an African raptor
Behavioral Ecology
Disassortative mating in color-polymorphic raptors is a proposed mechanism for the maintenance of... more Disassortative mating in color-polymorphic raptors is a proposed mechanism for the maintenance of color polymorphism in populations. Selection for such a mating system may occur if there are fitness advantages of mating with a contrasting morph. In the black sparrowhawk (Accipiter melanoleucus), mixed-morph pairs may have a selective advantage because they produce offspring that have higher survival rates. Two hypotheses, which may explain the mechanism, are the “avoidance-image” and “complementarity” hypotheses. The first suggests that, within a predator’s territory, prey develop a search image for the more commonly encountered parental morph, for example, the male morph during incubation and brooding. Females of a contrasting morph to their partner would then have higher capture rates once they commence hunting in the later nestling phase. Thus, the “avoidance-image” hypothesis predicts higher provisioning rates for mixed-morph pairs. Alternatively, the “complementarity” hypothesi...
Gender-related morphometric differences in mature and nestling Crowned Eagles, with comments on ringing of eagle nestlings in KwaZulu-Natal, South Africa
Ostrich
Crowned eagle nest sites in an urban landscape: Requirements of a large eagle in the Durban Metropolitan Open Space System
Landscape and Urban Planning, 2016
• 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.
Crowned eagle nest sites in an urban landscape: Requirements of a large eagle in the Durban Metropolitan Open Space System
Landscape and Urban Planning, 2016
• 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.
The study of diet is pivotal in understanding a species, particularly for quantifying a predator... more The study of diet is pivotal in understanding a species, particularly for quantifying a predatory raptors’ economic niche and potential for human-wildlife conflict. The crowned eagle (Stephanoaetus coronatus) is one of Africa’s apex predators and a population is present within the urban greenspace mosaic of Durban and Pietermaritzburg, KwaZulu-Natal, South Africa. In close association with urban development, the local population of crowned eagles has the potential to be a concern to the safety of domestic stock and pets. Time-lapse cameras were positioned at urban nest sites (n=11) to identify the prey composition during breeding, particularly in regards to taxa with human associations. The numerical proportion of avian prey, particularly hadeda ibis (Bostricia hagedash) pulli, was several times greater than any previous diet description. The methodology used and the abundance of hadeda ibis in these urbanenvironmentsarepotential contributing factors. Rock hyrax (Procavia capensis)was the primary prey and where hyrax were unavailable, the diet composition was broader and included more vervet monkeys (Chlorocebus pygerythrus). It was found that domestic stock comprised 6 % of the identifiable prey. Contrary to popular belief, no dogs (Canis familiaris) andfew cats(Felisdomesticus) weredelivered tothe nest bybreedingeagles in this study. The negative consequences of small proportions of pet losses should be considered against the majority of wildlife prey consumed, which also have various wildlife conflict interactions. Juvenile and sub-adult eagles are most frequently identified at in situ attacks of pets, particularly toy dog breeds. Further research on juvenile dispersal and winter diet will provide insights on the ecological impacts of eagle management strategies in the region.