Egg Rejection by Cowbird Hosts in Grasslands
Bibliographic record
Abstract
Abstract We tested Field Sparrows (Spizella pusilla), Vesper Sparrows (Pooecetes gramineus), Lark Sparrows (Chondestes grammacus), Grasshopper Sparrows (Ammodramus savannarum), Dickcissels (Spiza americana), Eastern Meadowlarks (Sturnella magna), and Western Meadowlarks (S. neglecta) to determine whether the low level (<10%) of observed parasitism by Brown-headed Cowbirds (Molothrus ater) on these grassland hosts is a result of egg rejection. Western Meadowlarks rejected 78% of artificial and real cowbird eggs, Eastern Meadowlarks rejected 36% of artificial cowbird eggs, and Dickcissels rejected 11% of artificial cowbird eggs. None of the other hosts regularly rejected cowbird eggs. Thus, egg rejection may account for some, but not all, of the low level of observed parasitism on grassland hosts in the Midwest. Meadowlarks were also tested with nonmimetic eggs, and the remaining hosts were tested with undersized mimetic and nonmimetic eggs when possible. All hosts, with the exception of the Field Sparrow, demonstrated some level of rejection of the nonmimetic eggs. These results suggest that some grassland hosts, which apparently have been in contact with cowbirds the longest, have evolved some form of rejection behavior that might have selected for mimetic eggs in cowbirds. The intermediate levels of rejection by both species of meadowlarks also may indicate that rejection is increasing in these populations.
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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 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.011 | 0.003 |
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; both teacher heads agree on what is shown here.
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".