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 female Eastern Screech-Owls (Otus asio) was examined during the pre-breeding periods in 1990 and 199 1. Male screech-owls increased singing rates and both males and females increased movement rates after removal of mates. Increased song output and movement appear to represent attempts 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-owls sang more and moved more than females after mate removal, suggesting either that males place a higher priority on re-establishing contact 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 after mate removal, suggesting that bounce songs are more important in intersexual communication. Extended bounce songs were given more frequently after mates were released, and were typically uttered near potential nest cavities. These songs may be used to draw attention to suitable nesting cavities, a resource that may be important in mate choice.