Th e vocal behaviour of birds may be infl uenced by many factors, including the risk of being detected by a predator. In Do ñ ana Protected Area, the tawny owl co-exists alongside its intraguild predator, the eagle owl Bubo bubo . We considered four scenarios to study the vocal behaviour of tawny owls at dusk by analysing: A) the calling rate of all males in 29 sites; B) the calling rate at dusk of males living within the home range of the intraguild predator; C) the calling rate of males living within the home range of the intraguild predator between 60 and 90 min after sunset; and D) the duration of male vocal bouts in visits where eagle owls have called. In scenario A we found that only the number of conspecifi c males aff ected the calling rate of tawny owls. In scenario B we observed that the presence of an eagle owl calling constrained the calling rate of the intraguild prey. In scenario C we found that this eff ect seemed mostly associated to a contemporaneous detection of the intraguild predator's calls. Finally, in scenario D we found no signifi cant eff ects on bout duration. Th ese results seem to indicate that tawny owls use their intraguild predator's calls as a cue to assess predation risk, and then adjust their vocal behaviour in order to minimize predation risk by a predator that may locate its prey by its vocalizations.

Lethal interactions can shape ecosystem structure, and consequently understanding their causes is ecologically relevant. To improve both empirical and theoretical knowledge on superpredation (i.e. predation on high‐order predators), we studied an eagle owl population, including its main prey and mesopredators, and then we crossed these results with existing theories to provide a reasoning framework. We fitted our field data into four main causes explaining lethal interactions: food stress, opportunistic superpredation, removal of a competitor, and removal of a potential threat. Empirically, superpredation seemed to be mostly determined by the combination of the food‐stress and opportunistic‐superpredation hypotheses, which highlights the complexity of the factors triggering superpredation. Therefore, besides being a response to lower food availability, superpredation may also represent an effective mechanism to remove potential predators and/or competitors, either intentionally or not. Our theoretical framework focused on the decision‐making process in superpredation, considering four inter‐related stages: encountering; attacking; and capturing a mesopredator; as well as consuming a mesopredator once killed. Superpredation almost certainly results from a complex process of decision‐making, accounting for costs and benefits assessed moment‐to‐moment and for each mesopredator individual. It is time to build bridges between theoretical and empirical studies to further understand the mechanisms driving complex interactions among top predators and mesopredators.

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