DISCRIMINATING OVERWINTERING ORIGIN AND MIGRATORY CONNECTIVITY IN A LONG-DISTANCE MIGRATORY SHOREBIRD STAGING IN THE CANADIAN PRAIRIES
Bibliographic record
Abstract
Migratory birds are experiencing widespread global declines. Shorebirds appear to be experiencing some of the most dramatic declining population trends, with the long-distance, Arctic-breeding migrants apparently losing ground the fastest. Challenges arise in monitoring these populations as they undertake impressive circumpolar migrations between breeding and overwintering areas. The ability to trace individual-level movements and assess the consequences of those decisions is critical as migratory connectivity is known to influence population demographics. I used both stable isotopes (δ 2H, δ13C, δ 15N) in winter-grown feathers and the Motus Wildlife Tracking System to track a northward migratory population of Sanderling (Calidris alba) in the Western Hemisphere. I examined geographic variation in feather isotope values from a northern population of Sanderling staging at Chaplin Lake, Saskatchewan over seven years and compared these to feathers collected at three disparate wintering locations separated by approximately 4000 km to classify individuals based on their overwintering moult origin. Feather isotope values in northward migrants were expansive (δ2H: −0.08 to −98.2; δ13C: −7.4 to −25.3‰; δ 15N: 5.9 to 24.5‰) and differed across known-origin wintering latitudes (27oN to 42oS). The range in δ2H values in birds captured in the Gulf of Mexico (GOM) was wider (δ2H: −1.3 to −98.2‰) compared to Peru (δ2H: −17.7 to −58.8‰) or Chile (δ2H: −46.0 to −77.1‰). Using discriminant function analysis, 85% of the sample population at Chaplin Lake could be classified to one overwintering area while the origins of 15% remained unknown. The majority (70%; range 52-70% across years) were assigned to the GOM, suggesting this is an important overwintering area for Midcontinental migrants. Northward departures of nanotagged Sanderling (Chile n = 23; Peru n = 11, GOM = NA) were primarily influenced by site with individuals from Chile departing on average 18 days earlier than those in Peru, but with no detectable differences in arrival timing at Chaplin Lake by individuals overwintering in the same area (Peru). Intermediate wind speeds appeared to predict earlier departure in Chilean birds. Using eight years of resight records and new isotope and nanotag data presented here, I confirmed the diversity of overwintering origins and migration routes for Sanderling that stage at a common northern Midcontinent site. These results have conservation implications as they provide a novel combination of banding, stable isotope, and radiotracking approaches to monitor changes in shorebird population structure and link these changes to overwintering origins and migratory schedules.
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 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 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| 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 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".