Does photo-monitoring affect nest predation?

We examined predation rates on natural and artificial Common Wood-Pigeon (Columba palumbus) nests with camouflaged cameras, with uncamouflaged cameras, and without cameras in Villatobas, Central Spain. Total daily nest survival probability was considerably higher in uncamouflaged-camera nests than in the two other types of nests, while there were no differences between the camouflaged-camera and the control nests. Survival probability of natural nests was similar to that of camouflaged-camera and control nests and significantly lower than that of uncamouflaged-camera nests. Any significant differences among nest types applied only to predation by Black-billed Magpies (Pica pica); predation rates by the garden dormouse (Elyomis quercinus) were similar in all experimental treatments. The results suggest that the presence of an uncamouflaged camera can affect Black-billed Magpies, which may become wary and avoid nests equipped with uncamouflaged cameras. The influence of photographic equipment on predation intensity in different species is an important factor that should be taken into account in studies using artificial nests. The use of control nests is recommended to evaluate the potential effects of the camera.