Estimating endogenous nutrient allocations to reproduction in Redhead Ducks: a dual isotope approach using δD and δ<sup>13</sup>C measurements of female and egg tissues
Bibliographic record
Abstract
Summary Clutch formation represents a considerable energy expense for waterfowl, yet little evidence is available to quantify nutrient allocation from endogenous and exogenous sources. Here we investigated hydrogen and carbon stable isotope ratios (δD and δ13C) in female Redhead Ducks (Aythya americana) and their eggs to evaluate the use of δD as an indicator of nutrient sources to reproduction. Females arrived with mean muscle tissue δD and δ13C values more positive than those of the local food web, reflecting marine dietary inputs from the wintering grounds. These values changed to the range of local food values by late incubation. δ13C values from albumen and yolk protein were correlated, supporting the presence of a common exogenous carbon source for these egg components. There was no significant correlation between δD or δ13C values in egg tissues and abdominal fat or muscle from the corresponding laying female. No general population‐level trends in isotope values from sequentially developing follicle yolks were found. Redhead females relied mainly on dietary lipids and proteins for egg production, and therefore endogenous reserves were used to satisfy female body maintenance and energy requirements.
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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 | 0.000 | 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) | 0.000 | 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".