Алексей Андрейчев » Публикация

Аннотация Both daily and seasonal year-round vocal activity of Ural owl were recorded in the Middle Volga River Region, Russia with the use of digital dictaphones. Two best-expressed peaks of longterm activity were revealed during the year: one starting in March and the other in September. In the spring, calls were recorded from 19:51 to 04:04. During this period, Ural owl’s total length of calls varied from 1 to 35 min per day, on average 12 min. The second annual peak was restricted to brood dispersal. In this period, the total duration of calls varied from 1 to 32 min per day, on average 9 min. In the spring, Ural owls always started calling from 24 min to 4 h after sunset. Vocalisation began at an average of 2 h 34 min after sunset. Completion of morning vocal activity always ended from 1 h 30 min to 2 h 40 min before sunrise.