Video Recording Reveals the Method of Ejection of Brown-Headed Cowbird Eggs and No Cost in American Robins and Gray Catbirds
Bibliographic record
Abstract
Despite the importance of knowing the method and cost of ejection in understanding the persistence of brood parasitism, anecdotal records of witnessed ejections of real Brownheaded Cowbird (Molothrus ater) eggs exist for only eight of ∼30 ejecter species. The probability of a host damaging its own egg while ejecting a parasite's egg is thought to be lower for hosts that grasp-eject, but grasp-ejection is an option only for hosts with appropriate bills. For hosts incapable of grasp-ejection, the cost of puncture-ejection may render acceptance adaptive. We video-recorded 12 ejections of real cowbird eggs by American Robins (Turdus migratorius) and 17 by Gray Catbirds (Dumetella carolinensis). With no damage to their own eggs, robins graspejected all cowbird eggs, whereas catbirds grasp-ejected 14 eggs and puncture-ejected three eggs. Our study revealed that a few species use a mixture of ejection methods and even large species may puncture-eject with little cost.
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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 | 0.001 |
| 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".