Marine predators such as seabirds, cetaceans, turtles, pinnipeds, sharks and large teleost fish are essential components of healthy, biologically diverse marine ecosystems. However, intense anthropogenic pressure on the global ocean is causing rapid and widespread change, and many predator populations are in decline. Conservation solutions are urgently required, yet only recently have we begun to comprehend how these animals interact with the vast and dynamic oceans that they inhabit. A better understanding of the mechanisms that underlie habitat selection at sea is critical to our knowledge of marine ecosystem functioning, and to ecologically-sensitive marine spatial planning. The collection of studies presented in this thesis aims to elucidate the influence of biophysical coupling at oceanographic fronts – physical interfaces at the transitions between water masses – on habitat selection by marine predators. High-resolution composite front mapping via Earth Observation remote sensing is used to provide oceanographic context to several biologging datasets describing the movements and behaviours of animals at sea. A series of species-habitat models reveal the influence of mesoscale (10s to 100s of kilometres) thermal and chlorophyll-a fronts on habitat selection by taxonomically diverse species inhabiting contrasting ocean regions; northern gannets (Morus bassanus; Celtic Sea), basking sharks (Cetorhinus maximus; north-east Atlantic), loggerhead turtles (Caretta caretta; Canary Current), and grey-headed albatrosses (Thalassarche chrysostoma; Southern Ocean). Original aspects of this work include an exploration of quantitative approaches to understanding habitat selection using remotely-sensed front metrics; and explicit investigation of how the biophysical properties of fronts and species-specific foraging ecology interact to influence associations. Main findings indicate that front metrics, particularly seasonal indices, are useful predictors of habitat preference across taxa. Moreover, frontal persistence and spatiotemporal predictability appear to mediate the use of front-associated foraging habitats, both in shelf seas and in the open oceans. These findings have implications for marine spatial planning and the design of protected area networks, and may prove useful in the development of tools supporting spatially dynamic ocean management.

A study of the Merriam's wild turkey was conducted March 1972 to August 1973 in southwestern Utah to determine the life history and habitat utilization. Using transects, bio-telemetry, and observational techniques, information on flocking, hen:poult and sex ratios, and approximate dates for spring dispersal, nesting, and hatching was obtained. Turkey observations in relation to habitat variables were used to determine habitat utilization. Except during the spring mating season, male flocks remained apart from other turkeys. Hen flocks in fall and winter consisted of adult hens and juveniles of both sexes. Males dispersed from winter flocks in March, and those that became harem gobblers attracted not more than 3 hens. Egg-laying probably took place from mid-April to mid-May and hatching from mid-May to mid-June. A drop in hen:poult ratios from 1:2.2 in 1972 to 1:0.7 in 1973 was attributed to harsh spring weather. Hens comprised an estimated 60 percent of the population during the study period. Turkeys utilized a faU-winter-early spring habitat of mountain brush and scattered ponderosa pine. Late spring use was associated with a ponderosa pine or aspen-mixed-conifer habitat type. Broods highly used glades dominated by an aspen overstory with intermingling mixed-conifer, while a male flock used mixedconifer clearings at 10,000 feet elevation. The upper and lower limits of turkey range on the study area were 10,000 and 6,000 feet, respectively. Turkeys began spring migration in April and fall migration in late September or early October.