The Singing Behavior of Eastern Screech-Owls; Seasonal Timing And Response to Playback of Conspecific Song

Eastern Screech-Owls (Otus asio) possess a repertoire of two song types, the bounce and the whinny. We examined (1) seasonal variation in the use of these songs in central Kentucky and (2) the responses of male and female screech-owls to the playback of bounce songs. The spontaneous use of bounce songs increased uring February and March, declined in April and May, increased again in June and continued through November. The spontaneous use of whinny songs increased ramatically during August and September and continued through November. Playback experiments revealed that (1) males uttered significantly more bounce songs than did females, and (2) owls responding with bounce songs were located significantly closer to the speaker than were those responding with whinny songs. Our results suggest, herefore, that bounce songs are directed to nearby conspecifics while whinny songs are directed to more distant individuals. Based on patterns of seasonal change in spontaneous use, we tentatively conclude that bounce songs are used in both aggressive and nonaggressive contexts while whinny songs are used in aggressive contexts.