The Role of Cavity Size in the Evolution of Clutch Size in Tree Swallows
Bibliographic record
Abstract
The individual-optimization hypothesis states that parents lay a clutch size that maximizes their own individual recruitment (Pettifor et al. 1988).Pettifor et al. (1988) found that when Great Tit (Parus major) nests were manipulated to an equal brood size, tits that began with a larger clutch size had higher recruitment than those that began with smaller clutches.They concluded that females lay the size of clutch that is optimal for their ability or quality as parents and that this clutch size varies as a result of intrinsic and extrinsic differences among individuals.In holenesting species, optimal clutch size may be selected to correspond to the maximum number of nestlings that can fit in a cavity at the least cost to reproduction.In this case, the intrinsic difference is parental quality, and the extrinsic difference is cavity size.This hypothesis has been supported by studies showing that clutch size is positively correlated with cavity size in hole-nesting passerines (Karlsson and Nilsson 1977; Rendell and Robertson 1989, 1993; Robertson and Rendell 1990; Rendell and Verbeek 1995).Rendell and Robertson (1993) examined the cavity/clutch size relationship in Tree Swallows (Tachycineta bicolor) via two experiments.The first determined that when given the choice between large (standard size) versus small (less than 50% of standard size) nest boxes, Tree Swallows preferred to nest in large boxes.Rendell and Robertson (1993) hypothesized that in small nest boxes, a reduced clutch size translates into reduced reproductive success.However, no significant differences in success (percent or number of young fledged) were found between large and small boxes, even when controlling for clutch size (experiment 2).Thus, the possibility that females were using box size as a predictor of future nestling conditions was rejected.However, the lack of a difference in reproductive success between large and small nest boxes may be explained by the fact that females in both large and small box types had the opportunity to optimize their clutch size to their environment.In this way, females may have selected the clutch size that was most appropriate to their environment (cavity size) and capabilities (parental quality), resulting in all females having approximately equal success, regardless of cavity size.Any reduction in reproductive success would indi-• Address correspondence to this author.
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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 | 0.003 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 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".