Effects of intra- and interspecific brood parasitism on a precocial host, the canvasback,
Bibliographic record
Abstract
Canvasback ducks (Aythya vaUimrria) suffer both intra- and interspecific brood parasitism. During 3 years in Manitoba, 80 % of canvasback nests (n « = 179 nests with completed dutches) were parasitized by redheads (A. amtricana), other canvasbacks, or both, with an average of 4.7 parasitic eggs per parasitized nest Parasitism had significant negative effects on the reproductive success of nesting canvasbacks, although the proximate mechanisms involved differed from those operating in altricial species. Accidental displacement of eggs when parasitic females forced their way onto host nests was the principal negative effect of parasitism, reducing the number of host eggs that were incubated and ultimately hatched. Parasitism by redheads was relatively more costly to canvasbacks than was intraspetific parasitism, with approximately 0.31 and 0.17 host eggs displaced per parasitic redhead and canvasback egg laid, respectively. No additional negative effects of parasitism on the hatchability of host eggs occurred subsequent to parasitic laying. Posthatch survival of canvasback ducklings was lower in broods from parasitized nests but was unrelated to the presence or absence of redhead ducklings. Canvasback hosts resisted intrusions by parasitic females but showed no evidence of discrimination against parasitic eggs or ducklings. Because most costs of parasitism in this system are inflicted at the time of parasitic laying, subsequent rejection of parasitic eggs or ducklings is probably of little benefit to canvasback hosts, while the evolution of behavior that might prevent parasitic laying in die first place, such as more vigorous nest defense, may be constrained by its high costs. Key words: Aythya americana, Aythya vahsmeria, canvasback, interspecific brood parasitism, intraspedfic brood parasitism, redhead. [Bthav Ecol 8:153~161 (1997)]
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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 | 0.001 |
| 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".