Effects of nest concealment on nest predation and cowbird parasitism, flight initiation distance and female stress levels in the Wood Thrush
Bibliographic record
Abstract
Temperate zone songbirds in North America can experience high levels of nest predation and Brown-headed Cowbird (<em>Molothrus ater</em>) parasitism, which may contribute to population declines, and an important question is whether nesting females can mitigate these threats through greater nest concealment. However, there is little known about the pros and cons of nest concealment to the incubating female, and whether concealment influences female corticosterone levels or nest escape behavior to potentially reduce risk of predation on females. This study investigates whether nest concealment resulted in reduced risk of nest predation and Brown-headed Cowbird parasitism in the Wood Thrush (<em>Hylocichla mustelina</em>), a forest bird that is declining across most of its range. We monitored nests (n = 186) in a highly fragmented forest landscape in southwestern Ontario, Canada and found high nest predation (53.2%) and moderate cowbird parasitism (25.3%). Overall nest concealment, nest height, and forest fragment size were not good predictors of daily nest survival or cowbird parasitism, but greater nest concealment one meter above the nest strongly reduced nest predation risk. We speculate that because most Wood Thrush nests are relatively low (< 2.5 m above ground), above-nest concealment may be effective against detection by avian nest predators. Overall nest concealment was not negatively correlated with flight initiation distance (FID) or positively related to baseline corticosterone level. This suggests that high nest concealment does not increase stress or personal risk to incubating females; however, nest concealment manipulations are needed to further explore whether any such trade-offs exist.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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".