Single and side-by-side high voltage powerlines cause similar rates of fatal bird collisions in southern Quebec, Canada, during fall migration
Bibliographic record
Abstract
Significant declines in bird populations have occurred since the 1970s in North America. Quantifying the effects of anthropogenic disturbances that cause direct mortalities may prove useful to mitigate further declines. We examined the collision mortality rate between birds and powerlines during fall migration in an area that supports a great abundance of waterfowl and numerous powerlines. Four rights of way were selected to carry out the collision mortality surveys in southern Quebec, Canada. We searched 7.2 km of rights of way, on average, every week for 4 weeks, during two consecutive years. We also quantified three biases that may underestimate the number of fatal bird collisions: scavenger (removal of carcasses by scavengers), observer (carcasses not detected by observers), and injury (carcasses not found due to injured birds flying too far away from the powerline to be detected). Twenty-nine carcasses were found and considered as collisions in 2018 and 2019. Nine were waterfowl carcasses, eight were aquatic birds, ten were passerines, one was a dove and another was a woodpecker. Observer detection was estimated to be 64% and the results indicate that scavenger and injury biases were null. We found no significant difference in collision rate between single and side-by-side powerline configurations (0.33 and 0.37 collisions per km-week) which means building powerlines next to each other to reduce land use fragmentation does not increase the number of collisions. This aspect could have important implications for bird conservation as many power companies favor building powerlines next to each other. No collision rate could be calculated specifically for waterfowl due to the absence of fresh carcasses during the survey periods. Given the absence of many nonresident species during six or more months of the year, the collision mortality rates observed for this group appear to be low despite the high seasonal influx of waterfowl during the fall. We suggest future research should focus on quantifying the large-scale effects of powerline collisions on small birds because this mortality cause may add to other already well-documented ones such as cats and window collisions.
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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 | 0.000 | 0.000 |
| 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 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".