An Appraisal of the Use of Hydrogen-Isotope Methods to Delineate Origins of Migratory Saw-whet Owls in North America
Bibliographic record
Abstract
Northern Saw-whet Owls (Aegolius acadicus) breed throughout the boreal forest of North America, but little is known about their population trends or distribution within this region. Analysis of stable hydrogen isotopes (δ2H) in feathers can delineate origins of a variety of avian migrants, but raptors are reported to have high intra-feather isotopic variance and mean δ2H values higher than predicted from δ2H isoscapes specific to raptor feathers, making assignment of geographic origin sometimes difficult. We examined the applicability of δ2H analysis of saw-whet owl feathers to delineating origins of migrants and to assessing differences in the migratory behavior of adult and young owls by using multiple generations of feathers from owls captured during fall migration at the Delta Marsh Bird Observatory, Manitoba, 2006–2007. Values of δ2H in saw-whet owl feathers were higher than predicted from a δ2H isoscape specific to raptor feathers and from patterns of movements inferred from analysis of band recoveries. This effect was pronounced in adults, while values of δ2H in feathers of hatching-year owls fell primarily within the range predicted for the boreal forest northwest of Delta Marsh. Significant differences in δ2H values among feather generations suggest that physiological or behavioral differences between adults and young give rise to greater 2H enrichment in adult feathers. These results indicate that current δ2H isoscapes for feathers cannot be used to track adult saw-whet owls reliably and further research into the mechanisms of 2H enrichment in owl feathers is required.
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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 | 0.012 | 0.010 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.003 | 0.002 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.002 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 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".