MIGRATORY CONNECTIVITY IN BICKNELL'S THRUSH: LOCATING MISSING POPULATIONS WITH HYDROGEN ISOTOPES
Bibliographic record
Abstract
The measurement of the abundance of naturally occurring deuterium (δD) in feathers grown in North America can provide geographical information on location where the feather was grown. Previously, we used this technique to link populations of Bicknell's Thrush (Catharus bicknelli) breeding in northeastern North America (to 46°N) with wintering grounds in the Dominican Republic. That study indicated the presence of a subpopulation of wintering birds with more depleted feather δD values than those measured on their known breeding grounds. This suggested either a more northerly or a higher altitude breeding source population than previously measured. We located two populations of Bicknell's Thrush in Quebec, Canada, at Mine Madeleine (49°N) and at Mont Gosford (45°N). The Mine Madeleine birds had feather δD values overlapping those of the unidentified subpopulation found wintering in the Dominican Republic. At Mont Gosford, hatch-year birds were more depleted in their feather δD values than after-second-year birds suggesting their more northerly origins and capture during the early fall migration period. Our study demonstrates how the stable-isotope approach can be used to document connectivity between breeding and wintering populations of migratory birds. Conectividad Migratoria en Catharus bicknelli: Localización de Poblaciones Perdidas con Isótopos de Hidrógeno Resumen. La medición de la abundancia de deuterio en estado natural (δD) en las plumas formadas en América del Norte puede brindar información geográ fica sobre la localización en donde se formó la pluma. Anteriormente usamos esta técnica para relacionar las poblaciones de Catharus bicknelli que se reproducen en el noreste de América del Norte (hasta 46°N) con las áreas de invernada en República Dominicana. Ese estudio indicó la presencia de una subpoblación de aves invernantes con valores de δD en las plumas por debajo de los valores medidos de los sitios conocidos de cría. Esto sugirió la presencia de una población reproductiva proveedora de individuos localizada más al norte o a mayor elevación que las registradas anteriormente. Localizamos dos poblaciones de C. bicknelli en Québec, Canadá, una en Mine Madeleine (49°N) y otra en Mont Gosford (45°N). Las aves de Mine Madeleine tuvieron valores de δD en las plumas que se superpusieron con aquellos de la subpoblación no identificada encontrada invernando en República Dominicana. En Mont Gosford, las aves del primer año de edad presentaron valores más bajos de δD en las plumas que aquellos encontrados en aves del segundo año de edad o mayores, sugiriendo un origen más boreal y que fueron capturadas durante el inicio del período de migración otoñal. Nuestro estudio demuestra como el mé todo de isótopos estables puede ser usado para documentar conectividad entre poblaciones reproductivas e invernales de aves migratorias.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| 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 | 0.001 |
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 teacher head, 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".