Vocalization of the Long-eared owl Asio otus

What is it about?

Both daily and seasonal year-round vocalizations of the Long-eared owl (Asio otus) (Linnaeus, 1758) were recorded in the Middle Volga River region, Russia with the use of digital dictophones. Voice recorders were installed in the daytime for up to 5 days. The maximum duration of continuous operation of voice recorders was about 140 hours. By the time the previous recording was finished, we would arrive and move the recorder to a different location. The Long-eared owl can be classified as a moderately vocalizing bird, with calls recorded during 3 spring months. Peak activity is associated with pre-incubation and incubation periods. In the spring months, calls of the Long-eared owl were recorded from 16.37 h to 03.43 h. In the spring, the Long-eared owl began to cry before sunset (from 1 hour 30 minutes to 3 hours 15 minutes) and after sunset (from 56 minutes to 3 hours 39 minutes). Vocalization started after sunset for an average of 50 minutes. Vocalization always ended before dawn (to 1 h 21 min). Statistically significant differences in the duration of vespers and morning vocalizations were obtained with the use Mann-Whitney U test (Z = -3.08; p < 0.05).

Featured Image

Photo by Erik Karits on Unsplash

Photo by Erik Karits on Unsplash

Why is it important?

Of interest is the similarity of the Long-eared owl concerning the timing of vocalization to sunset and sunrise compared to other species of owls. For Eagle Owl in Mordovia, evening calls were recorded, as a rule, 1 hour before sunset. The completion of the morning vocalization of the owl usually occurred 1.5 hours before sunrise (Lapshin et al. 2018). For the Tawny owl (Strix aluco) in the Moscow region, voice responses were recorded mainly after sunset, and for the Pygmy owl (Glaucidium passerinum) 1.5 hours before and after sunset (Sharikov and Shekhovtsov 2013). For the Blakiston's fish owl (Ketupa blakistoni) in Primorye, voice responses were recorded 20-40 minutes after sunset (Pukinsky and Pukinskaya 2011). Thus, we can say that the timing of vocalization to sunrise and sunset in different types of owls has a specific character. Spring and autumn distributions of calls of different species of owls by the time of day differ slightly.

Perspectives