CR2025_18 Migration strategies and activity in a wide-ranging tropical seabird

Lead Supervisor: Malcolm Nicoll, Institute of Zoology

Email: malcolm.nicoll@ioz.ac.uk

Co-supervisors: Emily Shepard, Department of Biosciences, Swansea University; Ken Norris, Natural History Museum

Seabirds have complex life cycles, with breeding attempts at colonies on land interspersed with migrations to non-breeding areas at sea. During these migrations seabirds may cover large distances, even moving between oceans (Egevang et al, 2010), and this requires adjusting their diurnal and nocturnal flight schedules to accommodate travelling, resting and foraging behaviours. How seabirds adjust their flight schedules varies substantially between species (Rayner et al, 2016) with some species flying primarily in the day, some during the day and night and some mostly at night. In part this variation in scheduling of behaviours will be down to the ecology of each species but will also be influenced by variation in the marine environment and the lunar cycle experienced during migration (Bonnet-Lebrun et al, 2021). Within species, migration routes may vary between individuals (Franklin et al, 2022), hence individuals within a population are likely to experience markedly different marine environments in terms of prey abundance and accessibility. How individuals respond to these differences through adjusting their flight scheduling and behaviours is poorly documented and limits our understanding of the potential flexibility there is within species to respond to climate change impacts in the marine environment. This project will make a significant contribution to this knowledge gap.

The migration ecology of the Trindade petrel (Pterodroma arminjoniana) at Round Island (Mauritius), in the tropical Indian Ocean, has been studied since 2009 using geolocation tracking devices (GLS) (Nicoll et al, 2017). Currently, migration routes have been documented for >200 adult petrels, typically lasting 6 months, encompassing the entire tropical Indian Ocean with substantial intra-individual variation in migration timing and routes (Figure 1) (Franklin et al, 2022). In addition, the initial migration (1-2 years) post-fledging of >20 juvenile petrels have been documented. GLS also record saltwater immersion data, i.e., when individuals are on the sea or conversely in flight, which can be used to determine flight scheduling and associated behaviours, e.g., travelling, resting and foraging. Round island petrels therefore provide an ideal study system to investigate how, between individuals, flight schedules and behaviours vary across large geographical ranges and contrasting marine environments.

Using the existing, unique, GLS-derived long-term data set on Round Island petrel migration the project can explore how flight scheduling and behaviours vary between individuals migrating to different, environmentally contrasting, areas of the tropical Indian Ocean and how any variation may be driven by variable, location-specific environmental conditions (e.g., sea surface temperature, primary productivity and plankton community composition derived from remote-sensed data) and fixed cyclic events such as the lunar cycle. This will allow us to understand the extent to which behaviours are fixed or flexible among adult petrels. Using the migration data for juvenile petrels there is the opportunity to then explore the evolution (ontogeny) of these behaviours as petrels acquire flight and foraging experience at sea after fledging from the breeding colony.

Prior research has shown that Round Island petrels are a hybrid complex of three Pterodroma petrel species (Booth Jones et al, 2017), with Trindade petrel being the most common. Trindade petrels colonised Round Island relatively recently and originate from the Trindade and Vaz Islands in the Atlantic (Brazil), where migration routes have been tracked (using GLS) for ~30 individuals by the Federal University of Rio Grande. This therefore presents a novel and interesting opportunity to compare how the flight scheduling and behaviours of this petrel compare in a new environment (Indian Ocean) with its original environment (Atlantic Ocean).

The student will be based in the world leading conservation research Institute of Zoology at the Zoological Society of London and registered at Swansea University in the Swansea lab for Animal Movement, with additional co-supervision from The Natural History Museum (London). The project will be supported by a CASE partnership with the project’s in-country partners, Durrell Wildlife Conservation Trust and Mauritian Wildlife Foundation. Further scientific support and data will be provided by the Federal University of Rio Grande (Brazil) and the Marine Ecosystem Research Group at University of Reading.

Training opportunities:

A potential student will receive training and access to resources to develop both quantitative scientific skills and their field-based skills. The former will be developed through time at the Institute of Zoology (IOZ), at Swansea University in the animal movement group and at the marine ecosystem research group at University of Reading. Field-based skills will be developed through time at Round Island working with teams from IOZ, Durrell Wildlife Conservation Trust and Mauritian Wildlife Foundation conducting seabird surveys, tagging, ecology studies and island restoration activities.

Student profile: 

This project would be suitable for a student with a degree in biological sciences, ecology, marine ecology or equivalent related to environmental science and those who would like the opportunity to develop their quantitative research and field-based skills. Prior research (e.g., undergraduate or MSc/MREs project) or work experience in seabird ecology and/or animal movement ecology would also be highly relevant.

Please note: Due to the nature of this project and to comply with visa regulations, only Home students should apply.

Co-Sponsorship details:

The project will include a placement opportunity at Round Island (RI) Nature Reserve (Mauritius).

References

• Bonnet-Lebrun A-S, MP Dias, RA Phillips, JP Granadeiro, MdL Brooke, O Chastel, . . . P Catry (2021) Seabird migration strategies: Flight budgets, diel activity patterns, and lunar influence. Frontiers in Marine Science 8:683071
• Booth Jones KA, MAC Nicoll, C Raisin, DA Dawson, H Hipperson, GJ Horsburgh, . . . K Norris (2017) Widespread gene flow between oceans in a pelagic seabird species complex. Molecular Ecology 26:5716-5728
• Egevang C, IJ Stenhouse, RA Phillips, A Petersen, JW Fox, and JRD Silk (2010) Tracking of Arctic terns Sterna paradisaea reveals longest animal migration. Proceedings of the National Academy of Sciences 107:2078-2081
• Franklin KA, K Norris, JA Gill, N Ratcliffe, A-S Bonnet-Lebrun, SJ Butler, . . . MAC Nicoll (2022) Individual consistency in migration strategies of a tropical seabird, the Round Island petrel. Movement Ecology 10:13
• Nicoll MAC, M Nevoux, CG Jones, N Ratcliffe, K Ruhomaun, V Tatayah, and K Norris (2017) Contrasting effects of tropical cyclones on the annual survival of a pelagic seabird in the Indian Ocean. Global Change Biology 23:550-565
• Rayner MJ, N Carlile, D Priddel, V Bretagnolle, MGR Miller, RA Phillips, . . . LG Torres (2016) Niche partitioning by three Pterodroma petrel species during non-breeding in the equatorial Pacific Ocean. Marine Ecology Progress Series 549:217-229