Effects of Increasing Age on Fecundity of Old-aged Canada Geese (<i>Branta canadensis</i>)
Bibliographic record
Abstract
Senescence is a decline in body function with advanced age that manifests itself in birds as a decrease in survival rates or reproduction. Senescence is difficult to study in free-ranging birds because few birds reach old age and few studies last long enough to identify those birds that do. For 21 years, I studied lifelong reproduction among Canada Geese (Branta canadensis) nesting in New Haven County, Connecticut. These data were used to determine the impact of old age on female and male fecundity during the current year and during the remainder of the birds' lives. Old-aged geese were relatively common in this population; 15% of recruited geese lived 10 years, 3% lived 15 years, and one female lived 20 years. Females that nested when they were between 5 and 9 years old had a mean clutch size of 4.5, brood size at hatching of 3.4, and brood size at fledging of 2.9. Females that nested when they were at least 10 years old had a mean clutch size of 4.7, brood size at hatching of 3.4, and brood size at fledging of 3.3. These variables were independent of age for both sexes. Future reproduction (number of future nesting years and future production of eggs, hatchlings, and fledglings) declined with parental age for males but not females. Body mass of nesting birds did not change with age for either males or females. These results provided evidence of an effect of senescence in male Canada Geese but not females. The terminal investment hypothesis (i.e., that parental investment should increase as birds become older) was not supported for either sex.
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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".