The evolutionary processes that shape individual variation in continuous behavioural traits remain poorly understood. While the emerging discipline of animal personality is providing increasing evidence that consistent individual differences in behaviour have significant fitness consequences, cognitive traits are yet to be explored in the same manner. My general objective in this thesis was twofold. First, I aimed to examine the ecological significance and fitness consequences of the cognitive trait innovative problem solving-performance, using a population of great tits (Parus major). Second, I aimed to explore the mechanisms underlying the functional significance of ‘exploration behaviour’ a captive measure of the reactive- proactive personality axis, focusing specifically on foraging and risk-taking behaviour. This two-trait approach was expected to shed light on whether personality and cognition simultaneously influence fundamental behaviours. By carrying out behavioural assays on birds temporarily held in captivity, I showed that success at solving a food-motivated problem was repeatable within individuals, consistent between two different tasks and independent of exploration behaviour. Problem-solving performance was positively related to clutch size and fledgling number, established when birds were released back into the wild. Furthermore, when rearing offspring, solvers had shorter working day lengths than non-solvers and foraged over smaller ranges without compromising either provisioning quantity or quality. However, solver females were also more likely to desert their broods than non-solvers and consequently there was little evidence to suggest that directional selection acted on problem-solving performance. In comparison to non-solvers, solver males were also found to be poorer at competing for limited food resources during the winter. Together these findings suggest that costs and benefits are associated with problem-solving performance, which together may act to maintain variation in this trait. My thesis also provides some of the first evidence that exploration behaviour is related to both foraging and risk-taking behaviour in the wild. In comparison to relatively slow explorers, fast exploring males were better competitors at feeders during the winter. Relatively fast and slow explorers also differed in a number of foraging behaviours during offspring provisioning, although not always in the direction predicted from captive work on other populations. Finally, while exploration behaviour was positively correlated with risk- taking behaviour amongst breeding females during incubation, it did not predict nest desertion in response to the risk associated with being trapped by field workers. Collectively these findings suggest that personality measured in captivity has specific but not general power to predict behaviour in the wild. An important facet of evolution is that natural selection is rarely likely to act on a single trait in isolation owing to correlations between traits. This thesis demonstrates how important behaviours in the wild can be simultaneously linked to multiple sources of consistent behavioural variation. It also represents the first large-scale investigation of how variation in a cognitive trait relates to natural behaviour, reproductive life-history variation and fitness in wild animals. Using this individual-based approach in a natural setting may prove to be a useful tool for understanding how selection acts on cognitive traits.

Die Zielstellung dieser Untersuchungen bestand darin, das Präferenzverhalten von Schweinen, also die Bevorzugung unterschiedlicher Haltungssysteme bzw. Segmente von Haltungsverfahren, sensorgestützt zu ermitteln, um die Basis für eine Bewertung zu liefern. Den Tieren wurden Wahlmöglichkeiten zwischen jeweils zwei Liegebereichen mit unterschiedlichen Fußböden (vollperforiert, teilperforiert und planbefestigt) angeboten. Das Verhalten der 42 Schweine wurde kontinuierlich über die gesamte Versuchsdauer durch ein sensorgestütztes System erfasst. Die Identifikation der Schweine wurde durch einen Ohr-Responder gewährleistet. Jeder Kontakt mit einer Tiererkennung bei einem Wechsel zwischen den Aufenthaltsbereichen oder auch den Futterautomaten wurde über eine Datenleitung an einen PC übermittelt und gespeichert. Der gewählte Forschungsansatz ging davon aus, dass die Präferenz gegenüber verschiedenen Angeboten als eine Funktion der Zeit durch Besuchshäufigkeit und Aufenthaltsdauer dargestellt werden kann. Die Ergebnisse der eigenen Untersuchung zeigten hohe individuelle Unterschiede in der Ausprägung dieser Merkmale. Es stellt sich die Frage der Bedeutung dieser beiden Merkmale hinsichtlich der Beschreibung der wahren Präferenz. Deshalb musste eine Möglichkeit gefunden werden, Zeitabschnitte, die eine Ruhephase charakterisieren, von denen die dem Erkundungsverhalten entspringen von einander zu unterscheiden. Das Ziel dieser Unterteilung bestand darin, die Ruhephasen für die weiteren Auswertungen zu verwenden. Dadurch wurde offensichtlich, dass die Merkmale Ruhedauer und Besuchshäufigkeit zum Ruhen wesentlich geringere tierindividuelle Variationen aufweisen und somit eine bessere Basis für die Bewertung der Präferenz liefern. Unter Berücksichtigung der durchgeführten Analyse stellt die vorgestellte Auswertungsmethode ein sinnvolles Hilfsmittel dar, unterschiedlich gestaltete Ruhebereiche in Hinblick auf das Präferenzverhalten von Mastschweinen miteinander zu vergleichen. / The aim of this project was to analyse and evaluate the preference of fattening pigs concerning different floors in the resting area using sensor based identification. The experiment was aimed at contributing to a more objective evaluation of housing systems in pig production. Preferences were identified by letting the animals chose between two lying areas with different flooring (totally slatted floor, partly slatted floor and non-slated floor). The behaviour of 42 pigs was recorded continuously throughout the whole fattening period. Each identifications of pigs by entering or leaving the resting areas or by using the feeders and drinkers was transmitted by the data line to a PC and stored. The individual identification of the pigs was ensured by ear-responders. The basic approach assumes that the preference can be calculated as a function of time via the frequency of visits and duration of stay in accessible resting areas. The results of this study showed high individual variations of these characteristics. This raises the question of the relevance of these two characteristics in the description of the true preference. It is assumed that the pigs do not only visit the resting areas to rest, but also to satisfy their exploration behaviour. It is expected that only the long duration of stays characterize the preferred flooring system. Therefore a method should be developed to classify this kind of visit. The aim of this classification was to use only the resting period (the long visits in the resting area) for further evaluations. The results of this study showed that the characteristics rest duration and frequency of rest periods provides a better basis for the evaluation of preference behaviour. In the context of these investigations, the presented evaluation method was a useful tool to compare differently designed resting areas.