[Acoustically guided behavior in the early ontogeny of the long-eared owl: the characteristics of its feeding behavior and the parameters of the acoustic signal important for its stimulation].

Feeding behaviour of nestlings of long-eared owls (Asio otus) is manifested as a complex of two components, i. e., the vocal reaction (uttering of begging calls) and specific motor response. Exposure to the appropriate acoustic signals resulted in an increase in the number of begging calls and approaching reaction to the source of acoustic signals. The range of monotonal signals effective for eliciting feeding behaviour was 0.2--1.5 kHz, the most effective were the tones of 0.3--0.7 kHz. The approaching reaction to acoustic signals was rather weak up to the 5th day after hatching, clearly pronounced in the 6--11th days, and later on was abruptly substituted for the response of following the visual stimulus provoked by the acoustic stimulation. Specific acoustic afferentation is the sole stimulus for begging in nestlings up to 11 days of age, and it remains a triggering stimulus for feeding behaviour in owl nestlings throughout the period of artificial feeding under laboratory conditions (up to the 40th day after hatching.