Foraging Habitat Use and Diet Composition of Barn Swallows (Hirundo rustica) and Tree Swallows (Tachycineta bicolor) in Agriculturally Intensive Landscapes of the Northern Prairies
Bibliographic record
Abstract
Birds that catch insects while in flight, which comprise the guild known as aerial insectivores, have declined sharply over the last 50 years. The causes of these declines are incompletely understood but are hypothesized to relate to changes in aerial insect prey that lead to region- and species-specific changes in productivity and survival. One possible driver of such aerial insect changes is increasing agricultural intensity across the guild’s North American breeding grounds, as practices such as removal of natural habitat and increased insecticide use are known to affect insect communities. In this thesis, I studied the feeding ecology of two aerial insectivore species, Barn Swallows (Hirundo rustica) and Tree Swallows (Tachycineta bicolor), across a gradient of agricultural intensity in the Prairie Pothole Region of Saskatchewan, Canada. I sought to identify whether agricultural intensity affected the foraging behavior and diet of swallows, and to determine whether previously identified foraging differences between these species led them to respond differently to land use intensity. While I intended to also examine dietary insecticide exposure in relation to foraging and diet, this analysis was delayed as COVID-related closures of laboratory facilities prevented blood samples from being processed. Using data derived from GPS tags, I determined that both Barn and Tree Swallows selectively foraged in wetland habitats and avoided cropped habitat. Foraging habitat use was mostly consistent across the agricultural intensity gradient, but maximum foraging distance was affected by agricultural intensity among Tree Swallows but not Barn Swallows. Diet was similar between Barn and Tree Swallows, with both species, and particularly nestlings, frequently consuming emergent aquatic insects. Local wetland cover was a significant predictor of diet composition in both species of swallow, with wetland insecticide pollution also affecting diet among Tree Swallows. Collectively, these foraging and diet results indicate that there is a high degree of similarity in the feeding ecology of Barn and Tree Swallows in this Saskatchewan study system. This study highlights the importance of wetlands and emergent insects to multiple species of farmland-breeding aerial insectivores and indicates that conserving wetland habitats should be a conservation priority in the Prairie Pothole Region.
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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 | 0.000 | 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) | 0.001 | 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".