Seasonal declines in incubation periods of Brünnich's Guillemots <i>Una lomvia:</i>testing proximate causes
Bibliographic record
Abstract
In many species of bird, eggs laid late in the laying period hatch after a shorter incubation period than do eggs laid early. These seasonal declines in incubation period are generally thought to confer evolutionary advantages, but the proximate mechanisms that underlie them are poorly understood. Seasonal declines in incubation period are usually attributed to: (1) seasonal increases in ambient air temperatures; (2) seasonal changes in the behaviour of incubating birds; and/or (3) seasonal declines in egg size. In a previous study, Common Guillemot Una aalge incubation periods declined with laying date at a low‐Arctic colony. As there was no support for hypotheses 1 or 2, it was suggested that this occurred because egg size declined with laying date, but eggs were not measured in that study. We recorded similar seasonal declines in the incubation periods of the single eggs laid by Brünnich's Guillemots Una lomvia at two low‐Arctic colonies in four years. Neither seasonal variation in ambient air temperatures, nor in the behaviour of incubating adults, appeared to cause the declines. As predicted for Common Guillemots, incubation period increased with egg size among Briinnich's Guillemots, in one of two years. However, incubation period declined with laying date in the absence of corresponding declines in egg size. We conclude that none of the three commonly proposed proximate mechanisms adequately explains the seasonal variation in guillemot incubation periods. Several testable, alternative mechanisms are explored.
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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 | 0.001 | 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".