The Western Cape population of Blue Cranes (Anthropoides paradiseus) is the largest and most stable population for the species. The population is primarily threatened by high mortality due to collisions with power-lines and the development of wind farms. Yet, little is known about how this population uses the agricultural landscape and their movements. Thirteen Blue Cranes were fitted with trackers to collect Global Position System data and tracked for 3 – 18 months in the Overberg region of the Western Cape. With the provided spatial-temporal information, I estimated the home range size, daily flight distances, and distance travelled throughout the day of breeding and non-breeding cranes to determine whether the breeding status/season influences their ranging behaviour. There was no significant difference of the home range size between breeding cranes and non-breeding cranes (p > 0.05). There was also no significant difference of the home range size of breeding cranes between their seasons (p > 0.05). Breeding cranes travelled significantly shorter daily flight distances than non-breeding cranes (p < 0.05). Breeding cranes also travelled significantly shorter daily distances during the breeding season than the non-breeding season (p < 0.01). All cranes, regardless of breeding status or season, travelled further distances in the morning, decreasing distance during the midday and early afternoon with an increase in the late afternoon. Breeding cranes travelled shorter distances throughout the day than non-breeding cranes during the breeding season (p < 0.001). Lastly, breeding cranes travelled significantly shorter distances throughout the day in the breeding season than the non-breeding season (p < 0.001). From this study the results suggest that factors other than breeding status influence the ranging behaviour of these cranes. Factors such as the availability of roost and forage sites, the agricultural landscape of the Overberg and the presence of other Blue Cranes could also affect ranging behaviour. Although this study does not give clear guidelines on the movement of the population, it establishes a baseline for further studies into factors that affect their ranging behaviour and can still be used to aid in conservation strategies for the species. Future studies should focus on recording their time budgets, including overnight GPS fixes and assessing ranging behaviour over multiple years.

Diseases that infect wildlife populations pose a significant threat to public health, agriculture, and conservation efforts. The spread of these diseases can be influenced by the social structure of the population, and therefore often need to be accounted for in disease models. In this thesis I use high-resolution contact data to explore the social structure of a high-density population of European badgers (Meles meles). I explore how this structure might influence the spread of bovine tuberculosis (bTB), a debilitating disease of cattle for which badgers are a wildlife reservoir. Denning and home range data collected using radio tracking is also used to determine how this social structure is related to badger space use. I use social network analysis to identify the community structure of the badger population, revealing that badgers interact in fewer, more distinct groups than previously assumed. This is likely to inhibit the spread of disease through the population, given that the probability of infection entering a new social group will be reduced. However, among-group contact is still found to occur even between the most isolated groups. I show that this among-group contact is more likely to occur between less related individuals, possibly suggesting that breeding behaviour may drive among-group contact as a mechanism for inbreeding avoidance. To gain additional insight into this among-group contact, I determine how badger spatial behaviours are related. I show that the use of dens (setts) away from the social group’s main sett (outlier setts) in the spring is associated with extra-territorial ranging. I also show that this extra-territorial ranging is associated with more central network positions. The seasonality of this behaviour further suggests that this may be related to breeding activity. These findings suggest that behaviours associated with extra-group ranging may increase the risk of acquiring and transmitting infection. Therefore, use of outlier setts in the spring could act as a spatial proxy to identify high-risk individuals for disease spread, offering potential targets for disease control. Finally, I discuss the implications of these findings in regard to what they reveal about badger behaviour, disease transmission, and the design of effective disease control strategies. The importance of understanding population social structure for the study of wildlife disease in general is also discussed.

In the tradition of previous studies of threatened species, this thesis was undertaken with the aim of improving our understanding of the ecology of the White-winged Nightjar Caprimulgus candicans, and providing the information necessary to facilitate conservation efforts on its behalf. In 1998-2001, I studied a population of White-winged Nightjars at Aguará Ñu, an area of cerrado habitats within the Reserva Natural del Bosque Mbaracayù, eastern Paraguay. Over the course of three fieldwork seasons, I captured and ringed a total of 49 nightjars (34 adults and 15 young birds). Young females first bred at approximately one year old, while still in pre-definitive plumage. Young males exhibited a form of delayed plumage maturation, whereby they only attained definitive plumage following a prolonged moult spanning much of their first potential breeding season. No evidence was obtained to suggest that they succeeded in breeding while in this conspicuously intermediate state of moult. Considerable variation was noted in the plumage whiteness of definitive males, but no clear evidence was found for consistent age-related increases in white. During the breeding season, males defended small aggregated display territories, at which they conducted nuptial display flights between late August and early January. Female nightjars were responsible for all the parental care, and apparently visited male display arenas solely to obtain copulations. Chick paternity data confirmed that the study population was polygynous, with patterns of male aggregation suggestive of an exploded lek or 'landmark' mating system. Radio-telemetry studies showed that nightjars utilised home ranges of at least 20 to 40 hectares during the eight to ten months for which they were monitored. Home ranges contained a disproportionately large amount of young campo cerrado vegetation, but no forest or old campo cerrado habitats. When selecting foraging sites within their ranges, nightjars preferred younger and avoided older campo cerrado vegetation; wet grassland was utilised roughly in proportion to its availability. Observed patterns of habitat selection were potentially explained by the greater abundance of insect prey in younger habitats. When selecting daytime roost sites, nightjars preferred vegetation of intermediate age, reflecting their need for a balance between cover and ease of access. A more general analysis of patterns of sexual dimorphism within the Caprimulgidae showed that, although almost 80% of nightjar species exhibit some dimorphism of plumage whiteness, the study species was by far the most extreme case. The striking plumage of the male was partly explained by a strong positive relationship between wing white and openness of breeding habitats within the family. However, this failed to explain the complete absence of white in the female plumage, or the extent of white dimorphism shown by the species. The most likely explanation would appear to be that extreme plumage dimorphism occurred in conjunction with the evolution of polygyny and female-only care in this open-country species. The implications of these findings for the conservation of the White-winged Nightjar are highlighted, and recommendations are proposed for future work and conservation action.

The ranging behaviour, habitat preferences, genetic structure, and demographic parameters of bottlenose dolphins living in the Azores were studied using data collected from 1999 to 2004. Only 44 dolphins out of 966 identified were frequently sighted within and between years and showed strong site fidelity. The remaining individuals were either temporary migrants from within or outside the archipelago, or transients. Estimates of home range size were three times larger than previously reported for this species, possibly as a result of the lower availability of food resources. Mitochondrial DNA sequences showed very high gene and nucleotide diversity. There was no evidence of population structuring within the Azores. The Azorean population was not differentiated from the pelagic population of the Northwest Atlantic, suggesting the "unproductive" waters of the Atlantic do not constitute a barrier to dispersal. Population size, survival and temporary emigration rates were estimated using open-population models and Pollock's robust design. A few hundreds of dolphins occur in the area on a given year, though the majority should use it temporarily, as suggested by the high emigration rates. Bottlenose dolphins preferentially used shallow areas with high bottom relief. Temporal and spatial persistence of dolphin-habitat associations documented in this study further supports the idea of a close relationship between certain bathymetric features and important hydrographic processes and suggests the occurrence of prey aggregations over these areas may be, to some extent, predictable. Several results of this study suggest there are no reasons for concern about the status of this population. Yet, the resident group may be negatively affected by increasing pressure from the whale watching activity. Although the proposed Marine Park constitutes important habitat for resident dolphins, at present, the area is clearly insufficient to satisfy their spatial requirements and its conservation value may be limited.

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