Conservation reintroduction aims to establish an organism into an area from where it has disappeared or was extirpated. Monitoring is essential to identify the factors that underpin successful establishment and persistence of a self-sustaining population. The Great Bustard (Otis tarda) is globally threatened and became extinct as a breeding species in the United Kingdom (UK) in 1832. Trial releases began in 2004 to reintroduce the Great Bustard to the UK based on the release of captive-reared chicks transported from a source population in Russia. The aim of this research was to investigate the factors influencing the establishment of a founder population of Great Bustards in the UK. In Chapter 1, I set the context of the reintroduction science and management in the world today and explore the issues surrounding it. Chapter 2 sets the baseline by which to measure the Great Bustard reintroduction project using the first five years of releases (2004 – 2008). Estimating vital rates and modelling population growth, I show that low recruitment to the founder population is a limitation for establishment. Chapters 3 and 4 investigate post-release survival and dispersal, both important variables in population establishment. By modelling individual post-release survival I show that earlier date of release can improve survival and could be used to improve recruitment. Conversely, post-release dispersal had mixed implication for the management of the reintroduced population. Surviving Great Bustards incorporated the release site into their annual range and as their breeding site. However, the birds had traversed large areas reducing our ability to monitor and control the environment of individuals. In Chapter 5, the research focus moves from the reintroduction project to an examination of the impact of disturbance and conspecific attraction (presence of conspecifics positively influences the movement of individuals) in habitat selection in a small extant population of Great Bustards. I show that the spatial distribution of display sites is influenced by anthropogenic disturbance; however, the number of males attending the display sites is influenced by the abundance of female conspecifics. The management implications of this result are that the attraction to conspecifics is an important factor in habitat selection. Finally, in Chapter 6, I discuss project limitations, potential interventions and identify future areas of research.

abstract: The Great Bustard (Otis tarda) is an iconic species of the temperate grasslands of Europe and Asia, a habitat that is among the least protected ecosystems in the world. A distinct subspecies, the Asian Great Bustard (O. t. dybowskii), is poorly understood due to its wary nature and remote range in Siberia, Mongolia, and northern China. This subspecies is now endangered by rapid development. Using satellite telemetry and remote sensing, I investigated three aspects of the Asian Great Bustard’s ecology critical to its conservation: migratory routes, migratory cues, and habitat use patterns. I found that Asian Great Bustards spent one-third of the year on a 2000 km migratory pathway, a distance twice as far as has previously been recorded for the species. Tracked individuals moved nomadically over large winter territories and did not repeat migratory stopovers, complicating conservation planning. Migratory timing was variable and migratory movements were significantly correlated with weather cues. Specifically, bustards migrated on days when wind support was favorable and temperature presaged warmer temperatures on the breeding grounds (spring) or advancing winter weather (fall). On the breeding grounds, Asian Great Bustards used both steppe and wheat agriculture habitat. All recorded reproductive attempts failed, regardless of habitat in which the nest was placed. Agricultural practices are likely to intensify in the coming decade, which would present further challenges to reproduction. The distinct migratory behavior and habitat use patterns of the Asian Great Bustard are likely adaptations to the climate and ecology of Inner Asia and underscore the importance of conserving these unique populations. My research indicates that conservation of the Asian Great Bustard will require a landscape-level approach. This approach should incorporate measures at the breeding grounds to raise reproductive success, alongside actions on the migratory pathway to ensure appropriate habitat and reduce adult mortality. To secure international cooperation, I proposed that an increased level of protection should be directed toward the Great Bustard under the Convention on Migratory Species (CMS). That proposal, accepted by the Eleventh Conference of Parties to CMS, provides recommendations for conservation action and illustrates the transdisciplinary approach I have taken in this research. / Dissertation/Thesis / Doctoral Dissertation Biology 2015