High post-fledging survival and site persistence using mark-resight methodology for Oregon Vesper Sparrows in the Willamette Valley, Oregon
Bibliographic record
Abstract
The ecology of the post-fledging period for small passerine birds is one of the least known stages of the avian life cycle with high rates of mortality for many species. We examined post-fledging survival and site persistence of Oregon Vesper Sparrows (Poocetes gramineus affinis) based on extensive temporal and spatial implementation of mark-resight methodology in western Oregon, 2017–2021. Our analyses focused on a comparison of descriptive apparent survival estimates (i.e., return rates) uncorrected for detectability and modeled apparent survival estimates corrected for detectability using Program MARK. Modeled survival estimates were only slightly higher than descriptive survival estimates at three weeks (0.754 and 0.689), six weeks (0.659 and 0.617), and nine weeks (0.629 and 0.561). Both estimates were lowest at three weeks post-fledging (0.754 and 0.689), and higher in weeks 3–6 (0.874 and 0.897), and weeks 6–9 (0.954 and 0.893). The best supported model included an effect of fledgling age in weeks on survival probability, and additive effects of site, effort, and week of season on detection probability. There was a live resight during the post-fledging period of at least one bird from 94.9% of the successfully fledged nests. Site persistence greater than 50 days was 0.838. Mean site persistence was 78.1 days and longest site persistence for an individual bird was 115 days. Our results suggest that an extensive mark-resight effort can address detectability concerns and provide an approximation of true post-fledging survival estimates. Our post-fledging survival estimates are the highest reported for a grassland bird, and yet they contrast with the expectations of the methodology and the literature on post-fledging survival of grassland birds, which is mostly derived from radio-tracking methodology. These results along with recent meta-analyses from other researchers raise concerns about unreported and unknown but expected mortality in grassland nestlings and fledglings from additive predation due to radio-tracking attachments and devices.
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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 | 0.001 | 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 | 0.000 |
| 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".