Vocal interaction between Tawny Owl (Strix aluco) and Ural Owl (Strix uralensis) in the Middle Volga

Abstract

The work studied the co-vocalization of Tawny Owl and Ural Owl. Researched primarily using digital voice recorders. Co-vocalization was revealed only in spring. This is due to the breeding season of birds. The roll call of two species of owls was recorded 2 h 30 min after sunset. Co-vocalization was always observed from 21:00 to 22:00 hours. Duration of co-vocalization of the Tawny Owl and the Ural Owl ranged from several sec to 6 min. During periods of co-vocalization, the Tawny Owl managed to produce twice as many calls as the Ural Owl. The Tawny Owl was the first to start calling, and later the calls of the Ural Owl joined it. The Tawny Owl stopped vocalizing, and the Ural Owl continued to call after it. The calls of each of the two owl species in shared habitats were recorded primarily at different times. More often, the Tawny Owl began vocalization 30 min after the Ural Owl stopped calling. The natural and climatic conditions of the area in which co-vocalization was noted were studied. Co-vocalizations were observed in the temperature range from +3 to +7°C. Joint calls were recorded at wind strength from 4 to 7 m/s, at cloud cover from 40 to 90%, at pressure from 734 to 744 mm Hg.