From trips to bouts to dives: temporal patterns in the diving behaviour of chick-rearing Adelie penguins, East Antarctica
Breeding Adlie penguins forage at sea and return to land to provision their chicks, adjusting their foraging behaviour in response to environmental fluctuations over time. At Bchervaise Island, a nesting site in an East Antarctic population, Adlie penguin diving behaviour remains undocumented. This...
| Published in: | Marine Ecology Progress Series |
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| Main Authors: | , , , , |
| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
Inter-Research
2020
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| Subjects: | |
| Online Access: | https://doi.org/10.3354/meps13519 http://ecite.utas.edu.au/141561 |
| Summary: | Breeding Adlie penguins forage at sea and return to land to provision their chicks, adjusting their foraging behaviour in response to environmental fluctuations over time. At Bchervaise Island, a nesting site in an East Antarctic population, Adlie penguin diving behaviour remains undocumented. This represents a key area of uncertainty in efforts to understand and predict foraging success at this colony. Here, we compile a multi-year telemetry dataset from time-depth recorders deployed from 19922004 on 64 birds at Bchervaise Island. We examine diving activity at multiple scales: ranging from foraging trips (n = 125) to dive bouts (n = 3461) to individual dives (n = 84521). We characterise the stage- and sex-specific variation in diving behaviour of chick-rearing Adlie penguins using linear mixed effect models. Total foraging trip effort (trip duration, number of dives, vertical distance travelled and number of wiggles) substantially increased as the chick-rearing period progressed (guard through crche), consistent with increasing chick provisioning and self-maintenance requirements over time. Foraging activity was predominantly structured in periods of sustained diving bouts, indicating sustained foraging effort over the course of the foraging trip. Diving behaviour (dive-level depth, duration, bottom time and ACPUEd) varied in relation to sex and chick-rearing stage. Dives were performed more frequently during high and low levels of solar light which is likely linked to visual predation strategies or prey activity. Our findings advance our understanding of this populations foraging behaviour, which is ultimately required to underpin the conservation and management of this breeding colony. |
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