Tropical winter habitat limits reproductive success on the temperate breeding grounds in a migratory bird
Bibliographic record
Abstract
Identifying the factors that control population dynamics in migratory animals has been constrained by our inability to track individuals throughout the annual cycle. Using stable carbon isotopes, we show that the reproductive success of a long-distance migratory bird is influenced by the quality of habitat located thousands of kilometres away on tropical wintering grounds. For male American redstarts (Setophaga ruticilla), winter habitat quality influenced arrival date on the breeding grounds, which in turn affected key variables associated with reproduction, including the number of young fledged. Based on a winter-habitat model, females occupying high-quality winter habitat were predicted to produce more than two additional young and to fledge offspring up to a month earlier compared with females wintering in poor-quality habitat. Differences of this magnitude are highly important considering redstarts are single brooded, lay clutches of only three to five eggs and spend only two-and-a-half months on the breeding grounds. Results from this study indicate the importance of understanding how periods of the annual cycle interact for migratory animals. Continued loss of tropical wintering habitat could have negative effects on migratory populations in the following breeding season, minimizing density-dependent effects on the breeding grounds and leading to further population declines. If conservation efforts are to be successful, strategies must incorporate measures to protect all the habitats used during the entire annual cycle of migratory animals.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 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".