AVIS-IBIS

Birds of Indian Subcontinent

Use of Temperature Sensors to Monitor Patterns of Nocturnal Desertion by Incubating Common Terns

Publication Type:Journal Article
Year of Publication:2006
Authors:Arnold, JM, Sabom, D, Nisbet, ICT, Hatch, JJ
Journal:Journal of Field Ornithology
Volume:77
Issue:4
Date Published:2006
ISBN Number:02738570
Keywords:Bubo, Bubo virginianus, Colonia, Hirundo, Laridae, Sterna, Sterna hirundo, Strigidae
Abstract:Adult Common Terns (Sterna hirundo) reportedly respond to nocturnal predation by deserting colonies from the time of disturbance until dawn the following morning. However, direct evidence for this behavioral response is limited because the nocturnal behavior of individual terns is difficult to monitor due to low visibility and the vulnerability of terns to disturbance at night. We monitored the nocturnal incubation behavior of 10 pairs of nesting Common Terns using continuously recording temperature sensors disguised in dummy eggs and placed in the nests. Changes in egg temperature during the night suggested that a range of desertion behaviors occurred in response to visits by a Great Horned Owl (Bubo virginianus) that preyed on chicks and adult terns. As many as three desertion events (desertion at one or more nests in a single 12-min period) were detected on a single night and nests were unattended for an average of 54 min (range 8—352 min) per desertion event. Nest temperature sensors allowed us to detect individual responses to nocturnal predators and to determine that desertion behavior was more varied than previously assumed. Desertion events were most frequent when physical evidence indicated the presence of an owl in the colony and during nights after owl predation, suggesting that desertion is a response to the actual risk of predation as well as to the possibility of predation. /// Se ha informado a adultos de Sterna hirundo, en la etapa de incubación, abandonar la colonia durante la noche como respuesta a disturbios causado por depredadores. La evidencia directa para esta conducta esta limitada, porque es dificil el monitorear las aves durante la noche, debido a la poca luz a la vulnerabilidad de las colonias al disturbio. Monitoreamos la conducta nocturna de incubación de 10 parejas que estaban anidando, utilizando un sensor de monitoreo continuo de temperatura (bitácora electrónica de temperatura), camuflageado en forma de huevo. Cambios en la temperatura de la bitacora durante la noche sugieren que hubo abandono de los nidos en respuesta a la visita de un buho (Bubo virginianus) que depredó tando adultos como pichones. Al menos tres eventos de abandono de nidos (uno o más en un periodo de 12 minutos) fueron detectados en una misma noche y dichos nidos no fueron atendidos por un periodo promedio de 54 minutos (alcance 8—352 minutos) por periodo de deserción. Las bitácoras electrónicas de temperatura nos permitieron determinar la respuesta de individuos a depredadores nocturnos y documentar que la conducta de abandono era más variada que lo previamente asumido. Los eventos de deserción resultaron más frecuentes cuando la evidencia fisica indicó la presencia de un buho en la colonia y durante noches posteriores a la depredación. Esto sugiere que el abandono de colonias es una respuesta al riesgo inmediato de depredación como también a la probabilidad de ser depredado.
URL:http://www.jstor.org/stable/27639360
Short Title:Journal of Field Ornithology
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