Migration as flow: using hydrological concepts to estimate the residence time of migrating birds from the daily counts
Bibliographic record
Abstract
Summary Estimating the length‐of‐stay, the number of days a bird can be expected to stay at a site, at stopover sites is critical to understanding the migration ecology and estimating the population sizes of birds as they move between breeding and non‐breeding sites. Estimating the length‐of‐stay of migrating animals at stopover sites has an analogue in the hydrological concept of transit time, the amount of time that water spends in a reservoir, which can be calculated as a numerical integration of inflow and outflow rates with an underlying Storage Age Selection function. We used this approach to estimate the lengths‐of‐stay of migrating Western Sandpiper ( Calidris mauri ) and Dunlin ( Calidris alpina ) based on the time series of daily counts at two sites in British Columbia, Canada. The approach yielded mean transit times for Western Sandpiper during southward migration at Sidney Island that ranged between 9·6 days and 3·8 days, and showed a significant decline over time, 1992–2001, and is consistent with the estimates obtained from the capture‐mark‐resight studies. Transit times during northward migration at Roberts Bank, Fraser River Delta, based on the best available information ranged from 1·8 to 3·2 days for Western Sandpiper, and had a median value of 2·0 days for Dunlin, which is consistent with the estimates obtained from the radio‐telemetry studies. These results indicate that the hydrological flow models may offer a means to estimate the length‐of‐stay from the daily counts of birds during migration. The models present an opportunity for testing the alternate hypotheses concerning the roles of behavioural‐ vs. habitat‐related mechanisms driving shorebird population sizes.
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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 | 0.001 | 0.001 |
| 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 | 0.001 |
| 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 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".