Sitting Ducks: The physiological and behavioural responses of incubating common eiders (Somateria mollissima) to heat stress in the Canadian Arctic
Bibliographic record
Abstract
Rising ambient temperatures driven by climate change can heighten an endotherm’s risk of heat stress, eliciting a physiological and behavioural response. Cold-specialist species may be particularly vulnerable to over-heating due to their adaptive ability to retain body heat in cold environments. Moreover, their risk of heat stress may be exaggerated during reproduction, when body temperatures and energetic workloads approach their annual maxima. In this study, I investigated whether a cold-specialist seaduck, the arctic-breeding common eider (Somateria mollissima), experiences heat stress during their incubation by examining their heart rate and incubation behaviour at Qikiqtakuluk (East Bay Island), a long-term breeding colony in the Qaqsauqtuuq (East Bay) Migratory Bird Sanctuary, Nunavut. Hens fast for roughly 25 days while incubating their eggs on sun-exposed nests. I used heart-rate data collected from incubating hens using a 3D-printed microphone egg in each nest during the summers of 2019, 2022, and 2023 (N= 62), as well as incubation behaviour recorded via temperature fluctuations from thermal probes in each nest in summers 2018, 2019, 2022, and 2023 (N= 86). Recorded nest-level temperature was also recorded at each nest using hobo temperature pendants, and site-wide ambient temperature and weather factors (e.g. wind) were also measured using heat-stress tracking devices. I found significant temperature thresholds at which eiders begin to increase their heart rate and increase behavioural adjustments on the nest in response to heat stress. However, eiders are not yet experiencing high-enough temperatures in their environment to show statistically significant changes in their heart rate and behaviour. In addition, we found that weather factors contribute to eiders' physiological responses but not behavioural responses to heat stress. Further, hens' heart rates and behavioural adjustments increase later in the breeding season and during later stages of incubation, with later-laying hens also having higher heart rates. We conclude that eiders are not yet significantly heat-stressed during their incubation, but as temperatures continue to rise beyond our found temperature thresholds, incubating eiders may begin to experience significant energetic and behavioural costs of heat stress, particularly later into the season and their incubation, with late-laying hens being especially vulnerable to energetic costs. We show that eiders have the capacity to respond to climate change, but that these responses can interfere with their reproduction. As such, the revealed temperature thresholds and assessment of eiders' vulnerability to heat stress under climate change’s warming of arctic summers may aid in informing their timely management and encourage protective policy action in this declining seaduck.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".