The influence of nest site characteristics on Asian tits (Parus cinereus) defense behavior

Birds can assess risk posed by predators in their environment and adjust their anti-predation strategies accordingly. However, the impact of nest site characteristics on nest defense behaviors has not been thoroughly studied. This study aimed to investigate the relationship between nest defense behaviors and nest site characteristics in Asian tits (Parus cinereus) when confronted with Common chipmunks (Tamias sibiricus, ground predator) and Eurasian sparrowhawks (Accipiter nisus, aerial predator). Generalized linear mixed-model analyses revealed that predator type significantly influenced both aggressive and vigilance behaviors, with Asian tits less likely to exhibit these two behaviors toward Eurasian sparrowhawks than toward Common chipmunks. Nest-site shrub height negatively predicted the probability of vigilance behavior, whereas no measured nest-site characteristics influenced aggressive behavior. Neither predator type nor nest-site features significantly affected stationary observation or threatening behaviors. These findings demonstrate that Asian tits adopt predator-specific defensive strategies: they adjust vigilance behavior s according to local shrub height while maintaining stationary observation and threatening behaviors relatively invariant, supporting their capacity for dynamic risk assessment in heterogeneous predation environments.