Annual survival rates of adult Red-necked Nightjars Caprimulgus ruficollis

Nothing is known about the survival rates of Nightjars. Here we estimate an nual survival rates of adult Red-necked Nightjars Caprimulgus ruficollis in and around the Donana National Park, southwest Spain. During the period 19 89-95, 557 adults were marked and 19.7% of them were recaptured at least on ce in subsequent years. Capture-recapture models were built to estimate sep arately survival and recapture probabilities. The final selected model show ed that probabilities of recapture differed between years (0.06-0.30) but n ot between sexes, and were independent of recapture effort. Survival was de pendent on the interaction between sex and rainfall, this effect being nega tive for females and positive for males. However, it is not clear why rainf all influences the survival of males and females differentially due to the lack of accurate information on other life history traits. Average adult su rvival 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).