| dc.description.abstract | Behavioural differences between urban and rural wildlife have been widely reported, however, how these differences relate to individual differences in behaviour and the expression of personality variation remains less well understood. In a review of studies exploring personality variation in urban wildlife, this thesis finds that many of these studies appear to consider behavioural variation (repeatable among individual differences in behaviour) within the context of quite broad classifications of urban verses rural populations. Using these broad classifications may lead to difficulties in understanding and predicting how urban habitats might shape behavioural variation. Maintaining behavioural variation is likely to be an important factor in populations undergoing rapid human induced habitat change, thus being able to compare between studies in terms the relationships between behaviour and habitat features, could be important for making predictions about potential impacts. Using grey squirrels as a model system, studies in this thesis attempt to address this issue by including habitat characteristics at the local habitat level into experimental field studies that investigate relationships between behavioural variation and habitat features associated with urbanisation. Firstly, it applies giving-up density (GUD) methodology to test for differences in risk perception and patch use in squirrels experiencing varying levels of urbanisation. This found that squirrels foraging near buildings and roads utilised ‘risky’ patches more readily than squirrels living further away from fixed features of potential disturbance risk. In addition, noise variability was found to be an important factor in squirrels perceived risk, with squirrels feeding under highly variable noise conditions leaving higher GUDs at ‘riskier’ feeding sites. To investigate the relationships between local habitat and personality variation, individual squirrels, at different sites, were measured on responses to handling and behaviours within an open-field test. This found that escape and exploration behaviours were repeatable for individuals, however, significant differences in personality variation between sites were not found. Local microhabitat features did not appear to significantly predict individual behaviours, although a trend for faster escape responses in individuals caught near roads was found at the urban site. Overall, differences in the mean levels of escape and exploration behaviours were found, with faster levels of escape responses and faster rates of exploration, although less total exploration, found in urban sites. These findings mirror those from other studies of personality variation in urban dwelling species, where levels of urbanisation experienced by populations were defined more broadly. Like many successful urban species, urban grey squirrels live at higher population densities than their rural counterparts. The final study in this thesis uses auditory playbacks of conspecific calls to test if features of the urban built environment influence behavioural responses during foraging under an auditory cue of potential competition risk. Results suggest that squirrels foraging closer to roads and buildings appeared to be less attentive to conspecific playbacks. Further, local habitat quality level and noise were also found to impact time invested in social signalling behaviours, vigilance and feeding intake rate. Together these results show that foraging trade-offs under potential conspecific risk vary with local habitat features associated with proximity to human disturbance. Foragers under variable noise conditions and those feeding close to urban features appear to prioritise resource-acquisition over attending to conspecific risk. Overall, the studies included in this thesis provide some insights into the behavioural differences between urban and rural grey squirrels in terms of resource-acquisition trade-offs, and the local habitat features affecting these. Integrating this approach into future studies of behavioural variation could aid in understanding of how urbanisation could impact behavioural variation in wildlife occupying these areas. | en_GB |
