Connecting Breeding and Wintering Habitats of Migratory Piscivorous Birds: Implications for Tracking Contaminants (Hg) Using Multiple Stable Isotopes
Bibliographic record
Abstract
Contaminant concentrations in migratory species are complicated by differential accumulation and elimination among geographically separated biomes. Double-crested cormorants ( Phalacrocorax auritus ) are used as monitors of Hg in North America; however, migration from northern breeding colonies to southern marine, freshwater, and aquaculture systems exposes individuals to spatiotemporal variations in contaminant uptake. We used stable isotopes (δ(34)S, δ(13)C, δ(15)N, δ(2)H) in primary feathers and a combined Bayesian assignment and isotopic threshold model to identify feather origins and the potential winter use of aquaculture (δ(34)S < 10‰, δ(13)C > -14‰), freshwater (δ(34)S < 10‰, δ(13)C < -20‰), and marine habitats (δ(34)S > 10‰). This approach allowed us to contrast body burden Hg derived from the breeding and wintering grounds, as well as from marine and freshwater habitats. We found feathers grown on Lake Winnipeg had greater Hg concentrations (mean = 4.26 ± 1.47 μg/g fresh weight; n = 20) than winter-grown feathers (3.19 ± 1.64 μg/g; n = 19), but Hg in winter-grown feathers was not related to any specific habitat. Isotopic assays of tissues of migratory birds allowed the source and degree of contaminant exposure to be identified throughout the annual cycle.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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".