On the Calls of the Collared Scops Owl Otus bakkamoena in Japan

KOBAYASHI (1954) and JAPB (1966) describe the call of the Collared Scops Owl Otus bakkamoena as "woz, woz" or "hoz, hoz, hoz". KIYOSU (1965), on the other hand, mentions that this species calls "pou pou, pou pou" in May and June. Although these authors implied that the calls they described are typical of the species, we have not observed Collared Scops Owls uttering such sounds. Their call that we have heard are quite different from those that have been described in books of Japanese birds. We have observed Collared Scops Owls on Miyake-jima, Izu Islands since 1978 and recorded the voice throughout the year. In this short paper, our observations on the calls and the seasonal fluctuations in calling frequency are reported. Fig. 1 shows the sonagram of the call uttered most commonly by Collared Scops Owls on Miyake-jima. It sounds like "koo" or "kwee" and is one syllable voice uttered at intervals of a few seconds. This call seems to be used in territorial defence and in communication between the male and the female of a pair. Incubating females often utter the call in the nest. Similar calls were also frequently heard before dawn at Lake Shoji on Mt. Fuji on May 4, 1978, although no tape recordings were made for detailed comparison. This kind of call is apparently the one most commonly uttered by the Japanese Collared Scops Owl. MARSHALL (1978) has reported the calls of south-east Asian populations of the Collared Scops Owl. According to his phonodisc and sonagrams, the regular calls of Thailand, Singapore and Sumatra populations are not dissimilar to those of Japanese birds. Their calls are also one-syllable and