Causes and consequences of within‐population variation in inter‐brood interval of a migratory songbird
Bibliographic record
Abstract
Many birds produce two broods each year and exhibit significant intra‐population variation in the length of time between the hatching of first and second broods (the inter‐brood interval). Why within‐population variation in inter‐brood interval occurs and whether longer inter‐brood intervals influence second‐brood survival remain key questions in understanding the benefits of producing a second brood. We examined the causes and consequences of variation in inter‐brood interval in a wild population of migratory Savannah Sparrows Passerculus sandwichensis breeding on Kent Island, New Brunswick, Canada. Using a 29‐year dataset, we show that females tended to have short inter‐brood intervals when their first nest was initiated later in the season, when they had a low number of first‐brood fledglings to care for, or when they had higher lifetime recruitment (suggesting that they were of higher quality). Males with the shortest and longest inter‐brood intervals had low feeding rates. Finally, structural equation modelling provided evidence that longer inter‐brood intervals led to later second‐brood hatch dates, which in turn led to smaller clutch sizes and fewer recruits. Our results suggest that the length of time between broods is a key factor predicting the first‐year survival of second‐brood offspring. These long‐term data reveal that inter‐brood interval reflects the timing of breeding and variation in female quality and that it influences offspring survival and, likely, fitness.
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".