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Minimum Survey Effort for Determining Sex Ratio of Wintering American Kestrels in a Large Area (Esfuerzo Mínimo para Determinar la Proporción de Sexos en Individuos Invernales del Falcón Americano (Falco sparverius))

Stephen J. Stedman
Journal of Field Ornithology
Vol. 60, No. 2 (Spring, 1989), pp. 259-263
Published by: Wiley on behalf of Association of Field Ornithologists
Stable URL: http://www.jstor.org/stable/4513429
Page Count: 5
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Since scans are not currently available to screen readers, please contact JSTOR User Support for access. We'll provide a PDF copy for your screen reader.
Minimum Survey Effort for Determining Sex Ratio of Wintering American Kestrels in a Large Area (Esfuerzo Mínimo para Determinar la Proporción de Sexos en Individuos Invernales del Falcón Americano (Falco sparverius))
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Abstract

Winter roadside surveys of American Kestrels in middle Tennessee revealed that 18 surveys (involving 196 sexed birds) conducted in 1985-1986 provided as precise sex ratio data as 48 surveys (involving 543 birds) and 38 surveys (involving 397 birds) conducted in the same region in 1986-1987 and 1987-1988, respectively; no statistically significant difference among the sex ratios resulting from data collected during the three survey seasons was detected. Furthermore, randomly selected pools of data from the 1985-1986 surveys, when analyzed, showed that precise sex ratio information can probably be generated by as few as 14 surveys (involving at least 176 sexed birds) in an area comparable in size to middle Tennessee. /// Censos de caminos llevados a cabo durante el invierno, sobre poblaciones del falcón americano (Falco sparverius) en Tennessee, revelaron que 18 censos (en donde se determinó el sexo de 196 aves) efectuados durante 1985-1986 arrojaron una proporción por sexo tan precisa como 48 (que envolvieron 543 aves) y otros 38 censos (que envolvieron 397 aves) que se llevaron a cabo en la misma región durante 1986-1987 y 1987-1988, respectivamente. No se encontraron diferencias significativas en las proporciones de sexos de estos falcones durante los tres periodos de estudio. Al analizarse data tomada al azar del periodo de 1985-1986, se econtró además, que se podía generar información apropiada sobre la proporción de sexos de estas aves con tan solo tomar los datos de 14 censos (envolviendo al menos 176 falcones) en un área comparable en tamaño a la estudiada.

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