Dens are a critical component of black bear (Ursus americanus) habitat, yet scale-dependent den-site selection has received limited attention. Natural and anthropogenic factors (e.g., vegetation, roads) may also influence bear den-site selection. I quantified black bear denning chronology and den use and evaluated multi-scale den-site selection in Mississippi, USA during 2005–2011. Females entered dens earlier than males and emerged later; multiple den use by both sexes in a single winter was common. I recorded equal numbers of tree and ground dens, with ground dens at higher elevations surrounded by dense vegetation. Chronology and other denning characteristics of bears in Mississippi were similar to other black bear populations in the southeastern United States. Bears exhibited scale-dependent den-site selection selecting sites with greater percentage horizontal cover and farther from roads. Greater percentage horizontal cover may provide security and increase energetic efficiency. Denning farther from roads likely decreases risk of human disturbance.

Behavioural responses can reveal important fitness trade-offs and ecological traps in evolutionarily novel contexts created by anthropogenic stimuli, and are of increasing conservation concern due to possible links to population-level impacts. This thesis illustrates the use of proxies for energy acquisition and expenditure within multivariate and state-based modelling approaches to quantify the relative time and energetic costs of behavioural disturbance for a deep-diving marine mammal (Physeter macrocephalus) in foraging grounds in Kaikoura Canyon (New Zealand) and near Lofoten Islands (Norway). A conceptual framework is first developed to identify and explore links between individual motivation, condition and external constraints to behavioural disturbance [Chapter 1]. The following chapters then use data from behavioural response studies (BRS) to: 1) derive biologically relevant metrics of behaviour [all chapters], 2) investigate effects of boat-based focal follows and tagging procedures [Chapters 2-3], and 3) relate responses to specific disturbance stimuli (distance, approach, noise) from whale-watching [Chapter 2], naval sonar and playback of presumed natural predator (killer whale Orcinus orca) sounds [Chapter 4]. A novel hidden state model was developed to estimate behavioural budgets of tagged sperm whales from multiple streams of biologging (DTAG) data [Chapter 3]. Sperm whales traded off time spent at foraging depths in a non-foraging and non-resting state in response to both tag boat presence, 1-2 kHz naval sonar (SPL 131-165 rms re 1μPa) and mammal-eating killer whale sound playbacks, indicating that parallel non-lethal costs were incurred in both anthropogenic disturbance and presumed antipredatory contexts. While behavioural responses were highly variable by individual, biologically informed state-based models appeared effective to control for variability in energy proxies across different functional contexts. These results and Chapter 5 “linking buzzes to prey” demonstrate that behavioural context is a signal that can aid understanding of how individual non-lethal disturbance responses can impact fitness.