Group size effect caused by food competition in nutmeg mannikins (Lonchura punctulata)
Bibliographic record
Abstract
When foraging group sizes increase, animals generally decrease the time devoted to antipredator detection and increase their foraging rate, the commonly reported group size effect. The increased foraging rate is thought to follow from increased safety from predators because as group size increases, more eyes are available to detect predators and the risk of being a predator's victim is diluted. This increased safety then allows higher feeding rates because individuals can reallocate time spent in vigilance to foraging. However, increased foraging rates can also be due to increased competition for resources as the number of companions increases. We tested whether increased feeding rates are the product of competition or antipredation when group size increases in nutmeg mannikins (Lonchura punctulata). We used edited video playbacks to change group size and type of competitor: vigilant only, feeding only, and controls. We found that the increased feeding rate associated with an increased group size only resulted when the companions were feeding. Video playbacks of nonforaging companions neither decreased an individual's use of vigilance while handling food nor did it release the full increase of feeding rate. Focal birds lowered their scanning time while feeding as the frequency of pecking by simulated nonvigilant companions increased. We conclude that the group size effect reported in nutmeg mannikins is not a product of safety benefits of group living but may also arise from the costs imposed by competition for resources.
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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".