Seasonally frugivorous forest birds and window collision fatalities: novel integration of bird counts in fall improves assessment of species vulnerability to collisions
Bibliographic record
Abstract
Bird-window collisions are a significant and growing threat to birds, but the issue is still understudied in many geographical areas and stages of the avian annual life cycle. The mountainous topography and numerous distinct biogeoclimatic zones along the Pacific coast of Canada and the United States may result in regional and seasonal differences in collision mortality and species vulnerability to collisions. We surveyed daily for evidence of bird-window collisions over six 21-day periods in fall, early winter, and late winter between 2019 and 2022 at a university campus in southwestern British Columbia, Canada, and assessed individual species' vulnerability to collisions by examining whether species-specific collision rates were disproportionate to their local abundance. We accounted for poor detectability of some species in fall, by integrating point count data from our study site with mist net capture data from a nearby banding station to improve abundance estimates. Collision mortality peaked in fall, but early winter collision mortality was significantly higher than in the later winter months, potentially due to movements of altitudinal migrants into our low-elevation study area in early winter. We estimated that an average of 885-1,342 (median = 1,095) birds are killed at 51 buildings campus-wide each year between September 15 and February 10, the peak fall migration wintering period. Forest birds, particularly species that switch to highly frugivorous diets in fall and winter, were most vulnerable to collisions across the seasons studied. Non-breeding season mortality due to collisions may be substantial for these species, particularly when considering cumulative mortality across the entire non-breeding period. The potential role of collision mortality in species declines should be further explored by assessing collision frequency and species vulnerability across life cycle stages in other geographical locations, and through improved data on migratory connectivity and linkages between declining breeding populations and non-breeding season mortality.
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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 | 0.002 |
| 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 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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 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".