Feather isotopes ( δ 2 H f ) and morphometrics reveal population-specific migration patterns of the Blackpoll Warbler ( Setophaga striata )
Bibliographic record
Abstract
Blackpoll Warblers (Setophaga striata) have declined precipitously according to the North American Breeding Bird Survey, but that survey’s coverage of the boreal breeding range is limited. Migration monitoring offers an attractive tool for additional assessment because migrants from inaccessible portions of the breeding range are included in counts. However, for site-specific trends to be combined into regional or range-wide population trends, the breeding ground origin of the migrants counted at each site must be known. Blackpolls have a loop migration pattern in which spring and fall migrants follow different paths, but very little is known about population-specific routes within North America. We used stable hydrogen isotope assays of tail feathers (δ2Hf, 4th rectrix) and wing-length measurements from migration monitoring sites across Canada and the northeastern United States to broadly delineate breeding/natal origins of blackpolls captured at those sites. Blackpolls captured on spring migration in southern Ontario and western Quebec had characteristics expected of birds from breeding range west of the Great Lakes. These birds travel northward from the eastern Gulf of Mexico to Canada east of the Great Lakes before turning westward to reach their final destination between northwestern Ontario and eastern portions of the Northwest Territories. Many birds sampled at Great Lakes sites prior to 2010, but not thereafter, had δ2Hf and wing-length characteristics expected of breeding range in eastern Canada, suggesting differential rates of population change among regions. Estimates of migratory connectivity indicated considerable mixing of populations from different portions of the breeding range during migration. Our results both corroborate and refine the known clockwise loop migration pattern, provide new insight into spring migration routes across North America, and provide a foundation for incorporating breeding ground origins into estimations of range-wide population trends based on standardized migration counts.
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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 | 0.000 | 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) | 0.001 | 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".