Ecology of migratory timing by southbound male and female Western Sandpipers (Calidris mauri)
Bibliographic record
Abstract
Western Sandpipers (Calidns maun) show the pattern typical of longdistance migrants of the family Scolopacidae, with male-biased parental care, female-first southward migration, and independent migration of age classes.I investigated the migratory timing of southbound Western Sandpipers, focusing on the period between departure from breeding sites and the first major stopover.A simulation model based on published breeding parameters predicted that females should precede males to post-breeding sites by 1.1-5.3d, which agreed well with data (2.3-8.3 d).At the first major stopover, the mean difference was only 1.2 days, but varied over 14 years from -7.8 days (females-first) to +2.3 days (males-first).Juvenile females preceded males by on average 0.5 d (-5.1 to +1.1 d, n=19).To examine this interannual variation, I compiled data on snowmelt, breeding phenology, and the migration of a n important predator, the Peregrine Falcon (Falco peregrinus).Snowmelt and falcon migratory timing varied greatly year-to-year, and were strongly correlated.These events bracketed sandpiper breeding and migration, which in contrast varied relatively little.Sandpipers migrated later relative to falcons in years with early snowmelt, which I infer makes the journey more dangerous.I compared predictions of five hypotheses about sandpiper migratory timing (Breeding Recovery, Migration Distance, Molt Deadline, Escape Performance, Territoriality) to data.I found strongest support for the hypothesis that migration timing results from a trade-off between benefits (more time for parental care or development) and costs (greater exposure to falcons) of delayed migration.Females weigh costs more heavily due to their poorer escape performance.To those who have encouraged me to spread my wings My deepest gratitude goes to my entire supervisory committee, Ron Ydenberg, Dov Lank and Tony Williams, for helpful criticism during design of my studies and on various drafts of my thesis, and for encouraging my growth as a scientist.My thanks to my senior supervisor, Ron Ydenberg
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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 | 0.001 | 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) | 0.000 | 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".