Predators can vary in the risk they pose, depending upon factors such as body size, maneuverability, hunting strategy and diet. Prey can also detect predators with different senses, such as seeing, hearing or smelling them. We presented wild Steller’s jays (Cyanocitta stelleri annectens) with visual cues (robotic raptors) or acoustic cues (call playbacks) of four different raptors to test how they assess risk and how this influences their alarm calls. The perception of risk from different predator cues varied with different species of raptors: sharp-shinned hawks (Accipiter striatus) were responded to as high threat regardless of whether they were seen or heard, whereas northern goshawks (Accipiter gentilis) were responded to as higher threat if they were seen over heard. Furthermore, Steller’s jays altered acoustic aspects of their alarm calls depending on the species of raptor, and whether they saw or heard them. These results demonstrate that Steller’s jay’s assessment of risk involves an interaction between predator identity and predator detection cue, and in response, they alter their acoustically-simple alarm calls in surprisingly nuanced ways.
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