THE EFFECT OF MATE REMOVAL ON THE VOCAL BEHAVIOR AND MOVEMENT PATTERNS OF MALE AND FEMALE EASTERN SCREECH-OWLS

The effect of temporarily removing mates on the behavior of male and f emale Eastern Screech-Owls (Otus asio) was examined during the pre-bre eding periods in 1990 and 199 1. Male screech-owls increased singing r ates and both males and females increased movement rates after removal of mates. Increased song output and movement appear to represent atte mpts either to re-establish contact with an absent mate or to attract a new mate. In support of the mate attraction hypothesis, five screech -owls apparently acquired new mates after mate removal. Male screech-o wls sang more and moved more than females after mate removal, suggesti ng either that males place a higher priority on re-establishing contac t with an absent mate or that males are more active in their attempts to attract new mates. Bounce songs were used more than whinny songs af ter mate removal, suggesting that bounce songs are more important in i ntersexual communication. Extended bounce songs were given more freque ntly after mates were released, and were typically uttered near potent ial nest cavities. These songs may be used to draw attention to suitab le nesting cavities, a resource that may be important in mate choice.