Demography of an alpine population of Savannah Sparrows
Bibliographic record
Abstract
ABSTRACT Although Savannah Sparrows (Passerculus sandwichensis) have been well studied across their North American range, few data are available for populations that breed in high-elevation habitats. We collected data over six years on the demography of a population of Savannah Sparrows (P. s. anthinus) breeding in alpine tundra and sub-alpine meadows in northern British Columbia, Canada. The mean duration of the breeding season at our site was 45.5 d, and pairs produced a maximum of one brood per season. Clutch sizes varied annually (mean = 4.37, range = 3.90 – 4.71 eggs). Nest fate also varied among years (range = 33 – 92%) due to variation in abiotic (weather) and biotic (predators) conditions. Uncorrected return rates of banded birds were 68% for adults and 17% for juveniles (N= 22 and 102, respectively). However, when resighting probability was taken into account, apparent annual survival was 75% for adults and 34% for juveniles. Compared to populations at lower elevations, Savannah Sparrows in our study had shorter breeding seasons, fewer broods per season, larger clutches, and higher adult and juvenile return rates. Our results suggest that Savannah Sparrows that breed in high-elevation habitats have adopted a low fecundity, high survival life history strategy that enables their persistence in these challenging environments. Aunque el Gorrión de Savanas (Passerculus sandwichensis) ha sido bien estudiado, a todo lo largo de su distribución en Norte América, hay muy pocos datos sobre poblaciones que se reproducen en hábitats de altas elevaciones. Presentamos los datos que recolectamos a lo largo de seis años sobre la demografía de una población de P. s. anthinus que se reproduce en la tundra alpina y sub-alpina en el norte de la Columbia Británica, Canada. El promedio de duración de la temporada reproductiva fue de 45.5 ± 30 días, y las parejas produjeron una sola camada por temporada. El tamaño de la camada fue variable (promedio = 4.37 ± 0.07, alcance = 3.90–4.71 huevos). La supervivencia de los nidos varió anualmente con una supervivencia diaria de 0.96 ± 0.01 (alcance = 0.87 – 1.00) y el número promedio de volantones por huevo puesto fue de 0.49 ± 0.06 (alcance 0.22 – 0.87). La tasa de retorno (sin correcciones) de aves anilladas fue de 68% para los adultos y 17% para los juveniles (N= 22 y 102, respectivamente). Sin embargo, cuando se tomó en consideración la probabilidad de reavistamientos, utilizando el programa MARK, la aparente sobrevivencia anual fue de 75% para los adultos y de 34% para los juveniles. Al comparar los resultados con los de poblaciones que viven en lugares bajos encontramos, en la población estudiada, una temporada reproductiva más corta, camadas mayores, pero menos por año y una tasa de regreso mayor para adultos y juveniles. Sugerimos que los gorriones que viven a altas elevaciones parecen haber adoptado una estrategia de vida de baja fecundidad pero de alta supervivencia que les permite persistir en ambientes sumamente retantes.
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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) | 0.001 | 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 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".