Nestling Sex Ratio in a Critically Endangered Dimorphic Raptor, Ridgway's Hawk (Buteo ridgwayi)
Bibliographic record
Abstract
Variation in nestling sex ratio is an important concept in population ecology, and has particular implications for the conservation status of small populations. Research on species exhibiting Reversed Sexual Size Dimorphism (RSSD), in which females are larger than males, have shown that significant biases in nestling sex ratios can result from demographic and environmental conditions experienced by parents during the breeding episode. We collected morphometric measurements from the critically endangered Ridgway's Hawk (Buteo ridgwayi) over a 4-yr period, verifying that the species exhibits RSSD. Females weighed 25% more than males and were significantly larger for 7 of 12 body measurements. Nestling sex-ratios were determined by PCR amplification of the CHD1 gene. The results revealed a weak but consistent trend toward female-biased broods for the small remaining population. Parents may potentially be producing more females, the more costly sex, due to an ample food supply and adaptive allocation of parental care. A female-bias sex ratio may also signal management concern for the species if it is caused by inbreeding; however, currently the bias is not significant enough to warrant immediate intense nest intervention or nest management for this critically endangered species.La variación en la relación de sexos en pichones es un concepto importante en la ecología de poblaciones y tiene implicancias particulares para el estado de conservación de poblaciones pequeñas. Investigaciones en especies que presentan Dimorfismo Sexual Invertido (DSI), en el cual las hembras son más grandes que los machos, han demostrado que los sesgos significativos en la relación de sexos de los pichones pueden ser el resultado de condiciones demográficas y ambientales experimentadas por los padres durante el episodio de cría. Colectamos medidas morfométricas de individuos de Buteo ridgwayi, una especie en peligro crítico, durante un periodo de cuatro años, verificando que la especie presenta DSI. Las hembras pesaron 25% más que los machos y fueron significativamente más grandes en 7 de 12 medidas corporales. La relación de sexos de los pichones se determinó por amplificación de RCP del gen CHD1. Los resultados revelaron una tendencia débil pero consistente hacia nidadas sesgadas hacia las hembras para la pequeña población restante. Los padres pueden estar produciendo más hembras, que representa el sexo más costoso, debido a un amplio suministro de alimento y a una distribución flexible del cuidado parental. La relación de sexos sesgada hacia las hembras puede ser una señal de preocupación en el manejo de la especie, si es que ésta es causada por endogamia; sin embargo, actualmente el sesgo no es lo suficientemente significativo como para requerir intervención de nidos de forma inmediata o manejo de nidos para esta especie en peligro crítico.
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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 | 0.003 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.010 | 0.001 |
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".