No description available.

Birds of prey are difficult to study and the status and distribution of many species is poorly known. As top predators usually occurring at low densities, raptors may be particularly sensitive to habitat degradation. Conservation of raptors might be vital to prevent further loss of species and ecosystems. Between April and December in 2008 and 2009, raptors and associated habitat data were surveyed using a distance sampling transect method in 70 randomly selected one square kilometre plots in the Cerros de Amotape National Park, the Tumbes National Reserve and buffer areas within the North West Biosphere Reserve in Peru. A total of 1261 detections of 19 diurnal raptor species were recorded. I examined community structure, diversity across land uses and relationships between abundance and niche attributes within species. Abundance and richness were highest outside protected areas and lowest in the national park. A Canonical Correspondence Analysis (CCA) of raptor species and habitat variables ordinated them according to latitude, elevation, percentages of vegetation cover, and, in some cases, individual tree species. I used logistic regressions (GLMs) to obtain habitat distribution models for eleven raptor species. Twenty eight habitat models were obtained and twelve habitat variables were included. Best models included measured percentage of vegetation cover at different strata, elevation and latitude. My findings suggest that vertical structure of forested areas is of particular importance for raptors in extreme northwest Peru. iii Density and population size estimates were calculated for 15 species using distance sampling line transect counts. Densities were stratified by time of detection (morning or afternoon) and by habitat type. Flying birds were included in the analysis. For all but two species, density estimates were higher in the morning than in the afternoon. Absolute density was higher than 1 individual km-2 for three species and for seven species it lay between 0.34 and 0.86 individuals km-2. Some species showed a marked preference for particular habitat types. I used generalized additive models (GAMs) to examine the relationship between the occurrence of six diurnal raptors and species diversity and abundance to vegetation structure, elevation and cattle „density‟ in 39 km² plots within my study area. Percentage of vegetation cover 5-15 m above the ground was the most important feature influencing the distribution of most species, including the rarer ones. Raptors responded differently to cattle density: Presence of species that foraged in open habitats increased with cattle density, while presence of range restricted or declining species decreased. Conservation efforts of raptors in extreme northwest Peru should also be conducted in areas outside the North West Biosphere Reserve by protecting remaining forests. Moderate cattle densities can benefit some species and help maintain a high raptor diversity in the study area. However, this activity should be strictly monitored so further fragmentation of forests and damage to vegetation structure is significantly reduced particularly inside the Tumbes National Reserve.

Predatory birds are vulnerable to contaminants in the environment due to their high trophic position and long lifespans. They are also important sentinel species so tools are needed to measure and monitor contaminants, not only to protect avian populations, but to confer protection to lower trophic species as well. Vibrational spectroscopy is an economic, high-throughput technique that can be used to determine biomolecular profiles and can also identify alterations induced by exposure to environmental contaminants. In this thesis, avian tissues and cells have been analysed for underlying biochemistry and for effects caused by exposure to common environmental pollutants, using attenuated total reflection Fourier-transform infrared (ATR-FTIR) and Raman spectroscopy techniques with multivariate analysis. By analysing untreated predatory bird tissues, vibrational spectroscopy was shown to reveal fundamental, underlying biochemistry. The ability to generate tissue-specific spectral profiles allows the identification of biomolecular compositional differences which may influence the effect of contaminant exposure. Brain tissue from wild, free-flying predatory birds was similarly analysed to assess the effects of ‘real-world’ contaminant exposure levels. Vibrational spectroscopy was demonstrated as a sensitive technique capable of distinguishing the effects of high and low contaminant exposures, protein secondary structures and elucidating sex- and age-dependant spectral differences. An avian cell line was also analysed using ATR-FTIR which was able to determine the biomolecular composition and identify significant differences between cell types. This not only verifies the suitability of such techniques for cell-based investigations but also shows they are sensitive enough to detect biochemical variations at the cellular level. ATR-FTIR was further demonstrated as a tool to identify alterations induced by single and mixtures of contaminants and as a screening tool to identify interactions in a mixture. Overall, vibrational spectroscopy was established as a sensitive tool to study the effects of environmental contaminants in avian tissues and cells, however, further research is necessary to fully validate the technique.

This thesis covers two broad areas of investigation; the conservation ecology of the European nightjar (Caprimulgus europaeus) nesting in lowland pine plantations in Eastern and Southern England and the application of phylogenetic methods to the Caprimulgidae. The nightjar has become a popular study organism with many studies involving the use of mist netting and attachment of GPS tags. However the effects of such close contact and potentially high degree of disturbance has not been studied systematically. The ecological work aimed to determine the effects of capture, instrumentation and blood sampling on breeding nightjars and also habitat selection for nesting and the importance of disturbance induced predation using artificial nests. Mist netting, telemetry and blood sampling had no effect on breeding success and no measurable long terms effects on philopatry or survival. Mist netting resulted in 0.75% mortality. Radio tagging caused short term reduction in activity and minor feather wear. Blood sampling caused temporary weight loss in bled chicks. We recommend that feathers are used instead of blood for DNA analysis. Telemetry showed that song territories (territory used primarily for nesting) of mated and unmated males were similar and nightjars shared airspace above territories so census workers should factor this into surveys. Male nightjars established territories on clearfell, plantations less than 10 years old and heathland but avoided plantations when the canopy has closed. Territory size varied by habitat (mean range 4.6ha to 9.3ha) but all territories had a compactness ratio (circularity) greater than 0.64 (where 1 = perfect circle). Nightjars located their nests adjacent to soft edges (broad transition of vegetation of similar height) and chose vegetation of intermediate density requiring a balance between nest concealment and vigilance. Artificial nests were created on habitat used by nightjars and baited with quail and plasticine eggs. Depredation was similar to nightjar nests however predation of nightjar and quail nests was mainly avian, whereas plasticine eggs were predated by mammals. These findings recommend future studies should avoid using plasticine eggs and use cameras to record predation events. Depredation was higher on clearfells and lowest in 4-9 year plantations and heathlands. Success of artificial nests on bracken dominated clearfells and < 4 year plantations increased when visited. Depredation was higher and more rapid in large territories and when adjacent to hard edges but lower and less rapid with higher vegetation density and territory compactness. The implications of this study are that controlled disturbance does not increase nest predation but that both real and artificial nest survival is dependent on optimal vegetation cover. These results have important implications for habitat conservation initiatives for this species nesting in commercial pine plantations. In the phylogeny work, cytochrome b was used as a probe. Bayesian analysis found that within the Caprimulgidae there were four geographically isolated clades with bootstrap support greater than 70%. Phylogeny suggests that the genus Caprimulgus is not monophyletic and is restricted to Africa and Eurasia and that Caprimulgus species from outside this area have been misclassified as a consequence of retention of primitive adaptations for crepuscular/nocturnal living. Future studies should use a more slowly evolving gene and include more taxa. The phylogeny was used to investigate the ecological correlates of bristle variation. Functional bristles were absent in the majority of the nighthawks and varied in the remaining two New World nightjar radiations and the Old World radiation. The length, number and stiffness of facial bristles on museum specimens of the Caprimulgiformes were measured A phylogenetically controlled comparative analysis suggested that rictal bristles have a mechanical role in protecting delicate head structures in general (habitat used for nesting) and foraging habitats. Complex foraging habitats selected for longer, more flexible rictal bristles that might have improved mechanoreception while such bristles were shorter in semi-open foraging habitats and vestigial in open habitats. Bristles are primitive and have become vestigial multiple times within this Order. These events are associated with habitat shifts leading to changes in foraging behaviour and selection on bristle characteristics, which in turn may have led to speciation.

This thesis explores how onboard instrumentation can be used to study how birds interact with the atmosphere, in particular to understand their soaring strategies and gust response mechanisms. The instrumentation unit consists of integrated sensors, including a GPS, IMU (inertial measurement unit) and pressure transducer, which provide accurate, high frequency measurements of the aerodynamics and kinematics of a free flying bird. The equipment development and derivation of parameters are initially presented. The data recorded from multiple flights of a steppe eagle (Aquila nipalensis) are then used to analyse the different aspects of its soaring flight throughout the rest of the thesis. First, the occurrence and mechanism of the wing tuck manoeuvre is investigated and found to be a gust response, precipitated by a drop in aerodynamic loading. It is suggested that this reduction in loading results in a moment imbalance on the wings, and that ultimately the wings are pulled down by an internal musculoskeletal moment. The bird's slope soaring behaviour is then studied by using CFD analysis to model the local updrafts for comparison with the bird's performance. The analysis shows that the bird predominantly flew in the regions of strongest updraft along the ridge but did not attempt to maximise gravitational potential energy. This leads to gliding flight and a review of the theoretical derivation of the classic glide polar. A sensitivity analysis of the polar to different drag coefficients highlights the need for more research into the selection of suitable values. The development of a new `soaring optimisation' chart to include the effect of wind conditions on the selection of best glide speed is presented. This is then compared with experimental glide data from the bird and used to determine the optimal drag coefficients for the polar model. Finally, a technique is developed for automatically identifying sections of thermalling flight and for removing the wind drift component to allow us to test thermalling behaviour. This exploratory analysis highlights the complexity of the flow structure within the thermal and the distinctly unsteady circling of the bird.

The seasonal migration of birds is one of the great phenomena of the natural world and satellite tracking provides a valuable means to analyse the behavioural and environmental factors that influence it. In this study satellite telemetry was used to track ospreys Pandion haliaetus during migration between the United Kingdom and West Africa. Autumn migrations were faster than those in spring, with more favourable meteorological conditions resulting in ospreys requiring fewer travelling days to reach their destination. They also incorporated time-minimisation techniques during southward journeys, indicating that selection-pressure influences migration speed in autumn as well as during spring migrations. The reclamation of winter territories is likely the key behavioural driver during autumn, particularly as later-departing individuals migrated faster. High resolution GSM-GPS transmitters provided new insights into the ability of ospreys to adapt flight method to environmental conditions, with tagged individuals exploiting thermal updrafts when available, but swapping to energy-demanding flapping flight when necessary. Very long ocean crossings, particularly across the Bay of Biscay, were regularly undertaken in autumn, when tailwinds aided progress. These flights were predominantly undertaken by flapping, but ospreys sometimes exploited weak thermals and elements of the wind to achieve soaring-gliding flight over the sea, the first time such behaviour has been documented. Individuals also regulated both flapping and gliding airspeed in response to changing wind conditions. Juvenile ospreys showed clear individual variation in the timing and speed of migration. Migration routes during the first migration were profoundly influenced by weather conditions, with wind drift resulting in very long flights across the ocean. It was also notable that ospreys with the longest post-fledging phase migrated fastest. Juveniles generally exhibited energy-minimisation techniques during migration, indicating that they were less time-constrained than adults. This may be particularly important given that individuals are likely to gain fitness advantages by arriving at the wintering grounds in good condition.

No description available.

The decline of worldwide vulture populations due to multiple anthropogenic threats is recognised as one of the most important issues in avian conservation due to the loss of the important ecosystem services that they provide. The Cape vulture (Gyps coprotheres) is endemic to southern Africa and is listed as Vulnerable by the International Union for Conservation of Nature due to declines across its range largely attributed to poisoning and fatal interactions with the expanding power line network. In this thesis I provide a first insight into the factors that drive the space use patterns of Cape vultures in an effort to inform future conservation strategies. I deployed Global Positioning System (GPS) tracking units attached to vultures caught from the wild in the main breeding range of the species in northern South Africa, and in north central Namibia where the species has recently been declared extinct as a breeding species but a small population remains. Tracking units were also deployed on three Cape vultures released in Namibia as part of a pilot reintroduction program. The GPS tracking data were used to delineate the size and extent of the vulture home ranges and to identify key factors influencing their movement patterns. Their relative use of unprotected and protected areas was assessed, as well as the influence of vegetation characteristics. Finally, I present the first approximation of the spatial niche of Cape vultures using ecological niche modelling methods and provide a first assessment of the potential impacts of climate change on their future occurrence. Immature individuals and two of the reintroduced vultures traversed extensive ranges (maximum home range > 975,000 km2) and regularly crossed international borders, while wild-caught adult vultures tended to show a higher degree of site fidelity while foraging across more restricted ranges (maximum home range < 150,000 km2) closer to known breeding colonies. The vultures tracked from South Africa regularly used transmission line towers as roost and perch sites which has allowed them to extend their foraging range beyond their historical distribution into areas previously devoid of suitable perches. Although some adults often roosted at breeding colonies inside officially protected areas, all of the vultures foraged primarily on unprotected or privately managed land. The vultures generally tended to forage in more open habitats. The ecological niche models indicated that bioclimatic variables such as precipitation seasonality were the key factors that influenced the space use of the tracked vultures. The models predicted that climate change could potentially result in significant pole-wards shifts of up to 333 km in Cape vulture occurrence patterns, putting the core breeding colonies in the north of their range under threat. This study has provided a first insight into the ranging patterns of Cape vultures using GPS tracking methods and has identified that their extensive ranges, frequent use of unprotected land and close association with power lines puts them at serious risk from multiple threats during their regular foraging activity. The findings of this study confirm for the first time that the threat of climate change to Cape vultures should be seriously considered when planning future conservation measures. This research has demonstrated the ability of GPS tracking methods to identify new threats and key areas for the implementation of conservation measures.

This thesis argues that humans and ospreys in Scotland are materially, bodily and ethically involved with one another. It follows that a separate human or osprey history of species conservation is inadequate. Focused primarily through the entwined experiences of birds and people on Speyside, I examine the unfolding of osprey-human relationships with particular attention to the agency and capacities of nonhuman animals as animals: with geographies and lives of their own. Drawing on the scholarship of Tim Ingold, Giles Deleuze and Donna Haraway, I consider the dwelling, the co-becoming, and the zones of attachment between human and osprey subjects. At the heart of this project has been an investigation of the relationship between the historical and geographical conditions within which osprey life has flourished on its return from extinction in Scotland, and the possibilities for osprey nature that emerge from such conditions. I offer a ‘site ontology’ of osprey involvements, each ‘site’ comprising a material, bodily and ethical event of agency, subjectivity and composition. Often running in parallel to each other, such sites emphasise differentiations of osprey life: their situation within the militarised biopolitics of bird protection and ‘Operation Osprey’; negotiations of avian-human proximity and distances; their nesting geographies amidst the experimental attempts to restore a diminished community to its former range; and the nature of avian existence emerging in the wake of a return from extinction. Drawing on an array of archival material – occasionally supplemented with oral history, avian science and encounters in the field – the thesis proposes a lively historical geography of animal involvement.

Face au déclin global de la biodiversité, de nombreux suivis de populations animales et végétales sont réalisés sur de grandes zones géographiques et durant une longue période afin de comprendre les facteurs déterminant la distribution, l’abondance et les tendances des populations. Ces suivis à larges échelles permettent de statuer quantitativement sur l’état des populations et de mettre en place des plans de gestion appropriés en accord avec les échelles biologiques. L’analyse statistique de ce type de données n’est cependant pas sans poser un certain nombre de problèmes. Classiquement, on utilise des modèles linéaires généralisés (GLM), formalisant les liens entre des variables supposées influentes (par exemple caractérisant l’environnement) et la variable d’intérêt (souvent la présence / absence de l’espèce ou des comptages). Il se pose alors un problème majeur qui concerne la manière de sélectionner ces variables influentes dans un contexte de données spatialisées. Cette thèse explore différentes solutions et propose une méthode facilement applicable, basée sur une validation croisée tenant compte des dépendances spatiales. La robustesse de la méthode est évaluée par des simulations et différents cas d’études dont des données de comptages présentant une variabilité plus forte qu’attendue (surdispersion). Un intérêt particulier est aussi porté aux méthodes de modélisation pour les données ayant un nombre de zéros plus important qu’attendu (inflation en zéro). La dernière partie de la thèse utilise ces enseignements méthodologiques pour modéliser la distribution, l’abondance et les tendances des rapaces diurnes en France. / In the context of global biodiversity loss, more and more surveys are done at a broad spatial extent and during a long time period, which is done in order to understand processes driving the distribution, the abundance and the trends of populations at the relevant biological scales. These studies allow then defining more precise conservation status for species and establish pertinent conservation measures. However, the statistical analysis of such datasets leads some concerns. Usually, generalized linear models (GLM) are used, trying to link the variable of interest (e.g. presence/absence or abundance) with some external variables suspected to influence it (e.g. climatic and habitat variables). The main unresolved concern is about the selection of these external variables from a spatial dataset. This thesis details several possibilities and proposes a widely usable method based on a cross-validation procedure accounting for spatial dependencies. The method is evaluated through simulations and applied on several case studies, including datasets with higher than expected variability (overdispersion). A focus is also done for methods accounting for an excess of zeros (zero-inflation). The last part of this manuscript applies these methodological developments for modelling the distribution, abundance and trend of raptors breeding in France.