Non-breeding behaviour and energy expenditure of red-throated divers (Gavia stellata)

• Main Authors: 3rd World Seabird Conference 2021, Duckworth, James
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: Underline Science Inc. 2021
• Subjects: Ecology; FOS Biological sciences; Animal Science; Petersen; Väisänen; Iceland
• Online Access: https://dx.doi.org/10.48448/ezxk-4153; https://underline.io/lecture/34761-non-breeding-behaviour-and-energy-expenditure-of-red-throated-divers-(gavia-stellata)

Abstract: Understanding how populations within a species can vary their response to seasonal stressors across spatial and temporal scales provides insight into the adaptability of that species. One species where such information is desired is the red throated diver (RTD, Gavia stellata), whose non-breeding season ecology is relatively unknown. RTDs are also predicted to be facing ever-increasing pressures from anthropogenic activity, making improving our understanding of this species all the more imperative. Physiological and behavioural models allow such a fundamental understanding of the ecology of a species. Here we used a combination of Light-based Geolocator and Time-depth Recorder devices to reveal non-breeding location and behavioural time budgets for RTDs from three different populations: Iceland, Scotland and Finland. Using allometric scaling equations and the knowledge gained from the behaviour budgets, we constructed models to estimate the energy expenditure of RTDs for the first four months of the non-breeding period. Our results show differing migration strategies across the three populations, with populations being migratory, partially migratory and resident. We found that both behaviour budgets and energy expenditure varied spatially and temporally, with migratory populations showing the largest degree of temporal change in their behaviour budget. We also found that energy expended on thermoregulation varied across the sites and that populations were able to overcome this additional stressor through physiological and behavioural adaptions. Our study answers several important questions about RTD behaviour and energetics, as well as more broadly providing examples of divergent non-breeding season survival tactics across spatial scales. This new information will enable us to carry out further work to examine how constrained RTDs are and their ability to adapt to increased anthropogenic pressure. Authors: James Duckworth¹, Sue O'Brien², Ib Petersen³, Francis Daunt⁴, Aevar Petersen⁵, Logan Johnson⁵, Petteri Lehikoinen⁶, David Okill⁵, Roni Väisänen⁷, Jim Williams⁵, Stuart Williams⁵, Jonathan Green¹ ¹University Of Liverpool, ²Joint Nature Conservation Committee, ³Aarhus University, ⁴UK Centre for Ecology & Hydrology, ⁵Independent, ⁶Avescapes, ⁷Aevscapes