1 The nocturnal activity of the Oriental free-tailed bat(Tadarida insignis) was deter-mined by visual observation, video recording and echolocation call recordings. The study site was the castle tower of Kumamoto Castle in Kumamoto City, Kumamoto Prefecture. The study period was from March 2013 to March 2016, it was when the castle was illuminated from sunset to 23:00 throughout the year.
2 The stone walls of the castle were used as a roosting site for T. insignis in spring, but it was highly likely that they moved to other locations during other seasons.
3 Illuminated areas attract insects, which are selected as a feeding ground by T. insignis. The bat made searching noises while circling in the sky and swooped down to pursue large flying insects.
4 The first echolocation call was often recorded within an hour after sunset, and the earliest was 12 minutes after sunset. The last sound was often recorded between 30 to 44 minutes before sunrise, and the latest was 16 minutes before sunrise. However, from June to September, the number of echolocation calls decreased and the time of first recordings tended to be later. In winter, calls were recorded intermittently, alt-hough the frequency decreased.
5 Continuous nighttime sound recordings for at least one week per season for at least one year are necessary to determine if T. insignis is present.
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