AVIS-IBIS

Birds of Indian Subcontinent

The Influence of Audio-Lures on Capture Patterns of Migrant Northern Saw-Whet Owls (La Influencia de Carnadas Auditivas en los Patrones de Captura de Individuos Migratorios de Aegolius acadicus)

Publication Type:Journal Article
Year of Publication:1999
Authors:Whalen, DM, Watts, BD
Journal:Journal of Field Ornithology
Volume:70
Issue:2
Date Published:1999
ISBN Number:02738570
Keywords:Aegolius, Aegolius acadicus, bias, Strigidae
Abstract:The effect of audio-lures on capture patterns of migrant Northern Saw-whet Owls (Aegolius acadicus) was assessed. The majority of new owls were captured within 12 m of the lure and capture frequencies decreased with increasing distance away from the lure. Recaptures tended to occur farther away from the audio-lure than new captures. Capture locations of foreign retrapped owls, however, were not significantly different than new owls. Although capture locations did not differ between adult and immature owls, there was a detectable size bias in the distribution of capture locations. Smaller owls tended to be caught farther away from the lure than larger owls. Our results demonstrate that when an audio-lure is used, a small number of mist nets is sufficient to capture substantial numbers of Northern Saw-whet Owls. However, studies targeting recaptures may benefit from the use of more nets spaced over a larger area. /// Se evaluó la influencia de carnadas auditivas en los patrones de captura de individuos migratorios de Aegolius acadicus. La mayoría de los buhos fueron capturados a unos 12 m de la carnada auditiva y la frecuencia de captura se redujo con el incremento de la distancia a que se colocó el aparato de sonidos. Las recapturas tuvieron la tendencia de ocurrir a mayor distancia de la carnada auditiva que la captura de individuos noveles. Sin embargo, la localidad de captura de aves reatrapadas no resultó significativamente diferente que las de buhos nuevos. Aunque no hubo diferencia en la localidad de captura entre buhos adultos e inmaduros, se pudo detectar un sesgo en la distribución de localidades de captura. Las aves más pequeñas tendieron a ser capturadas a mayor distancia de la "carnada" que las aves de mayor tamaño. Nuestros resultados demuestran que cuando se utiliza una carnada auditiva, un número reducido de redes de niebla es suficiente para capturar un número sustancial de individuos de Aegolius acadicus. Sin embargo, estudios dirigidos a la recaptura de individuos pudieran beneficiarse de la utilizacion de un número mayor de redes cubriendo una mayor cantidad de área.
URL:http://www.jstor.org/stable/4514397
Short Title:Journal of Field Ornithology
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