Hissing calls improve survival in incubating female great tits (Parus major)

Nest predation is among the most important selective pressure shaping nest-site selection and nest defense behavior in many avian species. In this study, we tested whether the production of one such nest defense behavior—hissing calls—may improve survival of incubating female great tits (Parus major). We found that 72.5 % of incubating females gave hissing calls when they were exposed to a stuffed woodpecker in their nest boxes. The repeatability of the number of hissing calls given was high, as was the latency to give the call. Additionally, natural nest predators attacked hissing and nonhissing females equally often. However, hissing females survived better than silent females. We tested responses of feral cats to playbacks of hissing call during their attacks of nest boxes and found that hissing calls prevented the predator attacks. Taken together, our findings indicate that hissing calls can deter predator attacks and potentially increase survival rates of nesting great tits or their offspring, or both. The propensity to give hissing calls may be related to personality type of incubating female great tits, which needs to be tested experimentally.