Reproductive Effort and Return Rates in the Mountain White-Crowned Sparrow
Bibliographic record
Abstract
Abstract We analyzed return rates of high-altitude-breeding Mountain White-crowned Sparrows (Zonotrichia leucophrys oriantha) in relation to five components of their previous season's reproductive effort: number of fledglings produced, double brooding, number of nesting attempts (first nests plus renests), total number of eggs laid, and fledging date. No relationship of return rate to reproductive effort occurred except in the case of fledging date. Fledging dates spanned a 2-month period from mid-June to mid-August. Returns of females to the study area held steady no matter when their chicks fledged in the previous breeding season, but male return rates increased significantly when their chicks fledged after 20 July. Coincident with that time frame, they entered molt and often withdrew parental care. We hypothesized that males in this montane environment, where thermoregulatory costs are high, traded off reproductive effort (parental care) with survival (return rates). This fits well with models of life-history evolution; however, the corresponding prediction that return rates of females with late-season broods should decrease due to their assumption of greater parental care was not supported. Apparently, the cost of reproduction shifted to the young: late-season nestlings grew more slowly, fledged at a smaller mass, and exhibited a fourfold increase in brood reductions. Their recruitment as breeders in the following season was also greatly reduced. Thus, a cost of reproduction was expressed in two forms, one as changes in survival rates of breeding males, the other as changes in quality of offspring. Esfuerzo Reproductivo y Tasas de Retorno en Zonotrichia leucophrys oriantha Resumen. Analizamos las tasas de retorno en las poblaciones reproductivas de alta montaña de Zonotrichia leucophrys oriantha con relación a cinco componentes de su esfuerzo reproductivo de la estación anterior: número de volantones producidos, eventos de dobles nidadas, número de intentos de nidificación (primer nido más re-nidificaciones), número total de huevos puestos y fecha de emplumamiento. No encontramos una relación entre la tasa de retorno y el esfuerzo reproductivo, excepto en el caso de la fecha de emplumamiento. Las fechas de emplumamiento se extendieron por un período de dos meses, desde mediados de junio hasta mediados de agosto. El regreso de las hembras al área de estudio se mantuvo constante, sin importar cuándo los pichones abandonaron el nido en la estación reproductiva anterior, pero las tasas de retorno de los machos incrementaron significativamente cuando sus pichones dejaron el nido luego del 20 de julio. En coincidencia con este momento, los machos comenzaron la muda y frecuentemente dejaron de cuidar a de los pichones. Hipotetizamos que los machos en este ambiente de montaña, donde los costos de termorregulación son altos, canjearon esfuerzo reproductivo (cuidado parental) por supervivencia (tasas de retorno). Esto se ajusta adecuadamente con los modelos de evolución de historias de vida. Sin embargo, la predicción correspondiente de que las tasas de retorno de las hembras con nidadas tardías deberían disminuir debido a la suposición de que brindarían mayor cuidado parental, no fue respaldada. Aparentemente, el costo reproductivo sería trasladado a las crías: los pichones de finales de la estación crecieron más despacio, dejaron el nido con menor masa corporal y exhibieron un incremento de cuatro órdenes de magnitud en la reducción de la nidada. Su reclutamiento como individuos reproductivos en la siguiente estación también se redujo enormemente. De este modo, el costo reproductivo fue expresado de dos formas, una como cambios en las tasas de supervivencia de los machos reproductivos y la otra como cambios en la calidad de la progenie.
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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".