Annual survival rates of adult Red-necked Nightjars Caprimulgus ruficollis |
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| Authors: | MANUELA G. FORERO JOSE L. TELLA DANIEL ORO |
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| Affiliation: | Department of Applied Biology, Estacion Biologica de Donana, Pabellon del Peru, Avda. Ma Luisa s/n, 41013 Sevilla, Spain;Department of Biology, University of Saskatchewan, Saskatoon, Saskatchewan S7N OWO, Canada;Instituto Mediterraneo de Estudios Avanzados IMEDEA (CSIC-UIB), Crtra. Valldemosa, km 7.5, 07071 Palma de Mallorca, Spain |
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| Abstract: | Nothing is known about the survival rates of Nightjars. Here we estimate annual survival rates of adult Red-necked Nightjars Caprimulgus ruficollis in and around the Donana National Park, southwest Spain. During the period 1989-95, 557 adults were marked and 19.7% of them were recaptured at least once in subsequent years. Capture-recapture models were built to estimate separately survival and recapture probabilities. The final selected model showed that probabilities of recapture differed between years (0.06-0.30) but not between sexes, and were independent of recapture effort. Survival was dependent on the interaction between sex and rainfall, this effect being negative for females and positive for males. However, it is not clear why rainfall influences the survival of males and females differentially due to the lack of accurate information on other life history traits. Average adult survival for the whole period was 0.74 for males (95% CI: 0.63-0.82) and 0.64 for females (95% CI: 0.56-0.72). |
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