Drivers of ocean movement patterns in Round Island petrels

Franklin, Kirsty (2023) Drivers of ocean movement patterns in Round Island petrels. Doctoral thesis, University of East Anglia.

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Among migratory bird species, shifts in phenology and distribution in response to changing environmental conditions are occurring across the world. Understanding the mechanisms through which these shifts occur, and thus the consequences for species conservation, relies on knowing the extent of within- and between-individual variation in migratory strategies, and their consequences for the conditions experienced by individuals. In this thesis, I use a global, multi-species, meta-analytical approach of published studies, a long-term (2009-2019) geolocator tracking dataset from a well-studied population of Pterodroma petrels on Round Island, Mauritius, in the tropical western Indian Ocean, and a field study of remote monitoring of petrel breeding ecology to explore these issues. These approaches revealed that repeatability in migratory timings is a common feature of avian migratory systems, yet is poorly studied in tropical systems, where resources are often patchy and unpredictable. Round Island petrel tracking helps to fill this knowledge gap, and their unusual hybrid status, year-round breeding, and monsoon-driven seasonal environment make them a model species for such questions. Repeat tracking of individual petrels revealed low levels of within-individual variation in migratory behaviour, but very high levels of between-individual variation, with petrels occurring across the Indian Ocean. Despite the huge area over which non-breeding petrels occur, petrel night-time activity patterns closely tracked the lunar cycle in all cases, including in migratory strategies used by very few tracked individuals. Deployment of remote cameras was successful at capturing individual petrel breeding events and citizen science processing of images produced only slightly lower estimates of breeding activity. Overall, the work in this thesis contributes to the understanding of migratory systems and how they can change, and of the conditions experienced by tropical seabirds.

Item Type: Thesis (Doctoral)
Faculty \ School: Faculty of Science > School of Biological Sciences
Depositing User: Chris White
Date Deposited: 23 May 2023 07:42
Last Modified: 23 May 2023 07:42

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