Resource competition among nestling red-winged blackbirds (agelaius phoeniceus)
Bibliographic record
Abstract
Red-winged blackbird ('Agelaius phoeniceus') females hatch their offspring asynchronously, creating mixed-aged broods comprising first-hatched "core" nestlings and later-hatched "marginal" offspring. Nestlings communicate their requirements to the parents using a combination of vocal and visual behaviours. Other studies of begging have focused solely on the need for food; here I incorporate thermal care as a resource. I begin by outlining the ontogeny of begging by red-winged blackbird nestlings using data collected from video-taped nests. My results indicate that parents use the collective begging efforts of the brood to assess both the thermal and nutritional requirements of the brood--the female parent responds to a weak collective effort by increasing nest attentiveness whereas a strong effect stimulates foraging. I compare the begging behaviour of core vs. marginal offspring at three phases of brood d6elopment, to determine whether developmental disparities influence the outcome of begging competitions. My results indicate that the outcome of begging competitions is primarily determined by size. Consequently, larger nestlings consistently receive more food. I develop a novel, non-surgical technique to mute nestlings temporarily in order to separate vocal from visual begging displays. My results indicate that food allocation is determined principally on the basis of visual displays, but that the foraging is regulated by the cumulative vocalizations of the brood. A secondary effect of the muting treatment is to reduce the length of time that nestlings beg, to which parents respond by increasing nest attentiveness. Finally, I compare parent-offspring interactions in unparasitised broods of red-winged blackbirds, to broods parasitised by the brown-headed cowbird ('Molothrus ater ') across the nestling period. Cowbird nestlings differ from host nestlings by maintaining a consist nt begging effort, and by begging for a lengthy period of time, particularly following the allocation of food. Host nestlings increase their begging efforts in response to the presence of the cowbird, but as they are unable to sustain the effort, parents do not increase foraging.
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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".