EffEcts of Extra Mass on thE PElagic BEhavior of a sEaBird
نویسندگان
چکیده
Resumen.—Los transmisores satelitales y los aparatos con sistemas de posicionamiento geográfico frecuentemente agregan un peso substancial a las aves a las que se los sujetan. Los estudios sobre los efectos de estos instrumentos se han enfocado en medidas indirectas, mientras que la influencia directa del peso extra en el comportamiento pelágico es poco conocida. Empleamos localizadores geográficos de 2.5 g para investigar el efecto del peso extra sobre el comportamiento pelágico de Calonectris diomedea mediante la comparación de los rasgos de un único viaje de forrajeo entre un grupo de aves que portaba pesos de 30 g, un grupo que portaba pesos de 60 g y un grupo control. Los pesos fueron colocados sobre la espalda de las aves usando las técnicas típicas para sujetar los transmisores satelitales a las aves marinas. El peso extra incrementó la duración de los viajes de las aves y disminuyó su eficiencia de forrajeo y el peso corporal adquirido en el mar. Estos efectos indirectos pueden estar relacionados con los rasgos de forrajeo: las aves con pesos suplementarios mostraron un esfuerzo de búsqueda mayor que las aves control, viajaron distancias más grandes, cubrieron un área de forrajeo mayor e incrementaron el ámbito máximo de forrajeo. Más aún, el tiempo pasado sobre la superficie del mar durante la noche fue mayor para los grupos con peso suplementario que para los grupos control, lo que mostró que el peso suplementario también afectó los patrones de actividad. Nuestros resultados destacan la necesidad de cuantificar los efectos del equipo de monitoreo usado comúnmente para estudiar el comportamiento pelágico de las aves marinas. Sugerimos que los localizadores geográficos pueden ser usados para obtener datos de control de los movimientos de los viajes de forrajeo y de los patrones de actividad.
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