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Territory Size and Movements of Florida Grasshopper Sparrows (Tamaño Territorial y Movimientos de Ammodramus savannarum floridanus)

Michael F. Delany, Clinton T. Moore and Donald R. Progulske, Jr.
Journal of Field Ornithology
Vol. 66, No. 2 (Spring, 1995), pp. 305-309
Published by: Wiley on behalf of Association of Field Ornithologists
Stable URL: http://www.jstor.org/stable/4514021
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.
Territory Size and Movements of Florida Grasshopper Sparrows (Tamaño Territorial y Movimientos de Ammodramus savannarum floridanus)
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Abstract

Florida Grasshopper Sparrows (Ammodramus savannarum floridanus) (n = 73) were color-banded and monitored on the U.S. Air Force Avon Park Range in southcentral Florida, 1989-1992, to obtain information on minimum area requirements and movements of this endangered subspecies. Estimates (100% convex polygon) of 30 breeding territories averaged 1.8 ha (SD = 0.96) and ranged from 0.6 to 4.8 ha. The mean territory size (95% convex polygon) of mated males was not significantly (P = 0.159) greater than that of unmated males. Population density was 0.0371-0.0614 territories/ha. Adults were sedentary, 21 of 25 resighted or recaptured individuals occupied the same breeding territories for 2-4 successive years. The maximum territory size and minimum population density suggest a minimum viable population of 50 breeding pairs may require 240-1348 ha of prairie habitat. Information on the breeding biology and winter ecology of the Florida Grasshopper Sparrow is needed to assess recovery efforts. /// Entre 1989 y 1992 se marcaron 73 individuos de Ammodramus savannarum floridanus con anillas de color y se estudiaron en los terrenos de la Base Avon de la Fuerza Aérea de los E.U.A. en la zona sur central de la Florida. El objetivo fue obtener información sobre los requisitos minimos de área y sobre los movimientos de esta subespecie en peligro de extinción. Estimados (polígonos 100% convexos) de 30 territorios reproductivos promediaron 1.8 ha (SD = 0.96) y variaron entre 0.6 y 4.8 ha. El tamaño territorial promedio (polígonos 95% convexos) de machos apareados no fue significativamente (P = 0.159) mayor que los de machos sin aparear. La densidad poblacional fluctuó entre 0.0371 y 0.0614 territorios/ha. Los adultos fueron sedentarios, 21 de 25 individuos redetectados o recapturados anidaron en los mismos territorios por 2 a 4 años consecutivos. El tamaño territorial máximo y la densidad poblacional mínima sugieren que una población viable mínima de 50 parejas requeriría entre 240 y 1348 ha de praderas disponibles. Se necesita información sobre la biología reproductiva y la ecología invernal de esta especie para establecer los esfuerzos pertinentes para recuperarla.

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