| Summary: | Tese de Doutoramento em Biociências, especialização em Ecologia, apresentada à Faculdade de Ciências e Tecnologia da Universidade de Coimbra. Seabird populations declined steeply in recent decades and their conservation status continues to deteriorate. Strategies and tools are therefore required to identify, predict, and mitigate the major sources of anthropogenic stressors affecting seabirds and the marine environment. Biologging emerged as a powerful tool to monitor biodiversity and reveal key information about the potential winners and losers of global change. By identifying important seabird habitats, tracking information can highlight areas for protection and contribute to a more sustainable exploitation of marine resources. In this context, seabirds can be used as indicators of global ocean’s health and marine spatial planning, a topic that is gaining momentum. Thus, in this thesis I investigated the influence of spatio-temporal variability of environmental conditions and anthropogenic pressures on the at-sea foraging decisions of a wide-range pelagic seabird, the Cory’s shearwater (Calonectris borealis). Combination of movement data, remote sensing and habitat modelling analysis are used to study the at-sea behaviour, foraging decisions and habitat use of Cory’s shearwaters across the North Atlantic Ocean. Main results of this thesis are: (1) seabird tracking is demonstrated to be essential for ecological investigation and towards the prioritisation of conservation goals (Chapter 1); (2) individual-level memory of resource availability and predictability can be an important mechanism explaining spatial foraging segregation within seabird colonies during the breeding period (Chapter 2); (3) Cory’s shearwaters from neritic and oceanic populations in the mid-North Atlantic Ocean exhibit contrasting foraging behavioural decisions in response to extreme phases of North Atlantic Oscillation (NAO) index (Chapter 3); (4) during the breeding season, Cory’s shearwaters rarely forage in the same areas as ...
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