Adaptations of co-vocalisation of non-owl birds with Eagle Owls (Bubo bubo) in natural and climatic conditions of Mordovia

Background. From the standpoint of studying relationships in the “predatorprey” system, joint vocalizations of predator birds and their potential prey are of particular importance. However, there is still very little information in the scientific literature about adaptations to the co-vocalisations of Eagle Owl and other bird species that do not belong to the Strigidae family. It is only known that this happens very rarely, and each case is of undoubted significance, because the Eagle Owl is a large owl, which is feared by many birds. In addition, before that it was not known under what meteorological conditions of the seasons of the year these interactions can occur. Therefore, the purpose of this study is to quantify the joint territorial calls of Eagle Owl with other birds under certain natural and climatic conditions of the region. Materials and methods. Registration of vocalisation of Eagle Owl and other bird species was carried out using digital dictophones. Cameral processing of the obtained audio recordings was carried out using the AIMP and Audacity programs. Meteorological conditions were analyzed according to the weather station Bolshie Berezniki. To assess the relationship between the co-vocalisation of birds and other parameters (temperature, wind strength, cloudiness and atmospheric pressure), the nonparametric Mann-Whitney U test was used. Results and conclusions. In the course of the research, co-vocalisation of Eagle Owl with the hooded crow, common raven, common cuckoo, common crane and european nightjars was revealed. Most of the registrations of co-vocalisations of Eagle Owl and other birds were noted during the twilight hours, timed to coincide with sunset or dawn, although a number of species are diurnal. Co-vocalisation was recorded in different seasons, but mainly in spring (64 %). Statistically significant differences in co-vocalisation were obtained with the use of Mann–Whitney U test for atmospheric pressure (Z = –4,72, p < 0,05) and wind strength (Z = –4,49, p < 0,05).